Latest / Boring Science / Betelgeuse Is Hiding Something Strange _ And We_re Finally Seeing It

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Betelgeuse Is Hiding Something Strange _ And We_re Finally Seeing It · Boring Science

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  Speaker 1: Hello, and welcome to Boring Science to Sleep, a quiet
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  Speaker 1: place where science becomes slow, soft, and easy to drift through. Tonight,
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  Speaker 1: you're going to gently explore Betelgeuse, the enormous red star
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  Speaker 1: glowing in the constellation of Orion. Not to learn everything
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  Speaker 1: about it, but simply to notice it slowly, calmly, and
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  Speaker 1: from a comfortable distance. You'll wander through its enormous atmosphere,
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  Speaker 1: its strange changes in brightness, its possible companion star, and
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  Speaker 1: the quiet motions hidden beneath its red surface. And before
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  Speaker 1: you settle in, if you truly enjoy these calm journeys
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  Speaker 1: through interesting facts about science, you're welcome to like this
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  Speaker 1: video and subscribe, only if it feels right for you.
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  Speaker 1: And when you're ready, let me know in the comments
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  Speaker 1: where you're listening from, and what time it is right now.
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  Speaker 1: It's always a quiet joy to see how many places
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  Speaker 1: and moments gather here together. Now, dim the lights, perhaps
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  Speaker 1: let a fan hum softly in the background. Allow your
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  Speaker 1: body to become comfortable and remember that there is nothing
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  Speaker 1: you need to do. You are safe. You can simply
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  Speaker 1: listen and drift. And when you're ready, let's slowly look
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  Speaker 1: toward the red light of Betelgeuse. There is a moment, perhaps,
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  Speaker 1: when the room around you becomes quiet enough that you
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  Speaker 1: can imagine the night sky above you. You do not
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  Speaker 1: need to stand outside You do not need to find
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  Speaker 1: a window. You can simply imagine the darkness above the rooftops,
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  Speaker 1: the familiar stars appearing one by one, and somewhere among them,
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  Speaker 1: the shape of Orion slowly becoming visible. Orion is one
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  Speaker 1: of those patterns in the sky that has been recognised
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  Speaker 1: for thousands of years, a quiet arrangement of stars that
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  Speaker 1: seems almost unchanged when you look at it from one
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  Speaker 1: night to another. And near one of its shoulders is
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  Speaker 1: a star that looks different from the others. a little warmer,
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  Speaker 1: a little redder. Its light has a soft, unmistakable colour.
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  Speaker 1: This is Betelgeuse. You can imagine it now as a
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  Speaker 1: small red point floating in the darkness, although the point
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  Speaker 1: you see is only the distant appearance of something unimaginably large.
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  Speaker 1: Betelgeuse is roughly 650 light-years from you. That means the
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  Speaker 1: light reaching your eyes tonight began its journey hundreds of
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  Speaker 1: years ago. long before the present moment had become the
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  Speaker 1: present moment for you. The light has crossed an enormous
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  Speaker 1: stretch of darkness, moving quietly between the stars, carrying with
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  Speaker 1: it an old image of the red supergiant in Orion.
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  Speaker 1: The source material identifies Betelgeuse as one of the brightest
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  Speaker 1: stars in the night sky, and describes it as the
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  Speaker 1: reddish star forming the left shoulder of Orion. So when
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  Speaker 1: you look toward Betelgeuse, You are not really looking at
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  Speaker 1: a star as it is right now. You are looking
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  Speaker 1: into the past. And perhaps that is a gentle thing
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  Speaker 1: to remember as you settle deeper into the night. You
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  Speaker 1: do not have to know what is happening far away
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  Speaker 1: at this exact moment. The light has already begun its journey.
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  Speaker 1: You only have to receive it. Betelgeuse belongs to a
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  Speaker 1: family of stars known as red supergiants. The name sounds grand,
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  Speaker 1: and in this case the name is deserved. Imagine taking
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  Speaker 1: our Sun and slowly, impossibly, allowing it to expand outward
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  Speaker 1: until its glowing outer layers stretch beyond the orbit of Mars.
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  Speaker 1: That is the scale we are beginning to approach. Betelgeuse
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  Speaker 1: has a radius nearly 900 times greater than the radius
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  Speaker 1: of the Sun, and yet there is something surprisingly gentle
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  Speaker 1: hidden inside that enormous size. Betelgeuse is only around 10
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  Speaker 1: times as massive as the Sun, so although the star
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  Speaker 1: is enormous, its material is spread across an immense volume
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  Speaker 1: of space. It is not like imagining a solid red sphere,
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  Speaker 1: packed tightly from the centre outward. Instead, much of its
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  Speaker 1: outer atmosphere is extraordinarily thin and diffuse. The source material
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  Speaker 1: emphasises this unusual combination of immense size comparatively modest mass,
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  Speaker 1: noting that its density is much lower than the Sun's
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  Speaker 1: and that its surface gravity is surprisingly weak. You might
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  Speaker 1: imagine a vast red cloud, gently glowing from within, a
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  Speaker 1: cloud so large that planets could disappear inside its outer reaches,
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  Speaker 1: and yet a cloud whose material is spread so widely
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  Speaker 1: that its outer layers are only loosely held by gravity.
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  Speaker 1: Gravity is still there, of course. It is still quietly
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  Speaker 1: pulling everything inward, but at the enormous outer atmosphere of Betelgeuse,
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  Speaker 1: gravity is not holding things with the same firm grip
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  Speaker 1: you experience here on Earth. And this helps explain why
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  Speaker 1: the surface of Betelgeuse is so restless. Because there is
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  Speaker 1: no solid ground there for you to imagine. No hard boundary,
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  Speaker 1: no quiet shoreline between star and space. Instead, the visible
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  Speaker 1: surface is part of a vast, glowing atmosphere. moving and changing,
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  Speaker 1: rising and falling. Deep within this enormous star, heat slowly
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  Speaker 1: travels upward, hot material rises, cooler material sinks, then the
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  Speaker 1: cycle begins again. You can picture it as an incredibly
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  Speaker 1: slow breathing motion, except the breath is made of glowing gas,
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  Speaker 1: and each region involved in the movement can be unimaginably
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  Speaker 1: larger than anything familiar to you on Earth. Astronomers describe
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  Speaker 1: these movements as convection, but you do not need to
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  Speaker 1: hold on to that word. You can simply imagine great
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  Speaker 1: warm regions slowly rising through the star, while cooler regions
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  Speaker 1: settle downward again, carrying heat through the enormous red atmosphere.
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  Speaker 1: The surface of Betelgeuse is therefore not perfectly smooth. It
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  Speaker 1: is more like a vast, slowly moving landscape of light.
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  Speaker 1: Some regions brighten, some fade, some rise, some sink, and
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  Speaker 1: some material can even escape outward into space. This is
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  Speaker 1: one reason Betelgeuse can appear so changeable from Earth. It
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  Speaker 1: is not a quiet lamp hanging in the sky. It
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  Speaker 1: is an enormous, ageing star whose outer layers are constantly moving.
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  Speaker 1: Computer models of the star show these great convective regions
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  Speaker 1: bubbling across its surface, a natural consequence of its immense size,
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  Speaker 1: low density, and weak outer gravity. And there is something
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  Speaker 1: peaceful in that image. From Earth, Betelgeuse looks like a
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  Speaker 1: tiny red point. But behind that tiny point is a
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  Speaker 1: world of slow motion. A world of rising gas and
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  Speaker 1: falling gas. A world of warmth moving through darkness. A
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  Speaker 1: world so distant that even its light must spend hundreds
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  Speaker 1: of years travelling toward you. You can let that distance
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  Speaker 1: become comfortable now. You do not need to reach Betelgeuse.
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  Speaker 1: You do not need to understand every movement happening there.
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  Speaker 1: You can simply imagine the enormous red star turning quietly
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  Speaker 1: in the darkness, its outer atmosphere breathing in its own
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  Speaker 1: ancient rhythm. And while you rest here, something inside that
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  Speaker 1: distant star continues to change. The changes are slow. Some
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  Speaker 1: take days. Some take years. Some unfold across times far
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  Speaker 1: longer than a human life. And eventually, far in the future,
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  Speaker 1: Betelgeuse will reach the final stages of its life, but
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  Speaker 1: for now it simply glows beside Orion, a small red
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  Speaker 1: light to your eyes, an enormous, restless world in reality.
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  Speaker 1: And between those two views of the same star, there
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  Speaker 1: is a great distance, filled with darkness, old light and time.
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  Speaker 1: You can simply remain here for a moment, listening, breathing.
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  Speaker 1: letting the red light of Betelgeuse drift quietly through your imagination.
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  Speaker 1: Because there is nothing you need to solve tonight, there
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  Speaker 1: is only a distant star, slowly changing, while its ancient
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  Speaker 1: light continues to arrive. There is something quietly strange about
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  Speaker 1: looking at a star, and knowing that, one day, it
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  Speaker 1: will no longer look the same. Betelgeuse is already approaching
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  Speaker 1: the final stages of its long life, But there is
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  Speaker 1: no clock hanging beside it, no glowing number in the
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  Speaker 1: darkness telling you how many years remain. And there is
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  Speaker 1: no calendar hidden inside the star that astronomers can simply
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  Speaker 1: open and read. Instead, there is only the star itself,
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  Speaker 1: slowly changing, slowly using the fuel that has supported it
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  Speaker 1: for millions of years. For now, Betelgeuse continues to shine.
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  Speaker 1: Its enormous outer atmosphere continues to move. Its great regions
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  Speaker 1: of hot gas continue to rise and fall, and deep inside,
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  Speaker 1: the story of its life is gradually approaching its final chapter,
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  Speaker 1: although that chapter may still be very far away. You
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  Speaker 1: may have heard that Betelgeuse could explode soon, and in astronomy,
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  Speaker 1: the word soon can be wonderfully misleading. Soon might mean
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  Speaker 1: a few decades. It might mean thousands of years. It
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  Speaker 1: might mean tens of thousands of years. And depending on
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  Speaker 1: exactly what is happening inside the star, the final transformation
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  Speaker 1: could potentially be separated from us by something closer to 100,000 years.
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  Speaker 1: So when astronomers say that Betelgeuse is nearing the end
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  Speaker 1: of its life, they are not saying that you should
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  Speaker 1: expect an explosion next week, next year, or even within
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  Speaker 1: your lifetime. They are describing a star that is very
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  Speaker 1: far along in a process that is almost impossibly long
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  Speaker 1: when measured against a human life. To understand why Betelgeuse
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  Speaker 1: will eventually explode, You can imagine a great fire, a
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  Speaker 1: fire that has been burning for an immense length of time,
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  Speaker 1: held together by a delicate balance. Deep inside a massive star,
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  Speaker 1: energy is produced by nuclear reactions. That energy pushes outward,
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  Speaker 1: gravity pulls inward. For much of the star's life, these
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  Speaker 1: two influences exist in a kind of quiet balance. The
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  Speaker 1: star does not simply collapse, it does not simply fly apart.
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  Speaker 1: it remains suspended between the two. But eventually, for a
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  Speaker 1: star as massive as Betelgeuse, the available nuclear fuel becomes
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  Speaker 1: increasingly difficult to use in the way that once supported
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  Speaker 1: the star. The inner regions change. The balance becomes different.
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  Speaker 1: And eventually, gravity can take over. The central core begins
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  Speaker 1: to collapse inward with extraordinary speed, while the outer layers
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  Speaker 1: respond to that sudden transformation. This is known as core collapse.
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  Speaker 1: You can keep that phrase softly in your mind. Core collapse.
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  Speaker 1: Not as a violent image, but simply as the inward
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  Speaker 1: movement of the deepest part of an enormous star. For
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  Speaker 1: a massive star like Betelgeuse, this is the pathway toward
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  Speaker 1: what astronomers call a type 2 supernova. The name is
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  Speaker 1: less important than the image. An enormous star reaches the
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  Speaker 1: end of the long process that has supported it. Its
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  Speaker 1: inner core gives way. and the star undergoes a tremendous
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  Speaker 1: final transformation. What remains at the centre can become something
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  Speaker 1: remarkably compact. A neutron star may be left behind, or,
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  Speaker 1: under the right conditions, the remnant may become a black hole,
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  Speaker 1: and around that quiet remnant the outer layers of the
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  Speaker 1: former star can be sent outward into space. But you
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  Speaker 1: do not need to imagine this happening tonight. you can
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  Speaker 1: let it remain somewhere in the distant future. Because the
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  Speaker 1: exact moment is one of the things we still do
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  Speaker 1: not know. The reason is simple, even if the physics
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  Speaker 1: behind it is complicated. You cannot look inside Betelgeuse directly.
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  Speaker 1: You can observe its light. You can measure its movement.
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  Speaker 1: You can watch its brightness change. You can study the
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  Speaker 1: material flowing away from its atmosphere. You can build models
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  Speaker 1: of what may be happening inside. But the deepest regions
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  Speaker 1: remain hidden beneath layers of enormous, glowing material. So scientists
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  Speaker 1: can estimate where Betelgeuse is in its life, but they
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  Speaker 1: cannot point to a particular evening and say, with certainty,
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  Speaker 1: that the explosion will happen then. And there is another
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  Speaker 1: quiet complication. The Betelgeuse you see is not Betelgeuse in
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  Speaker 1: the present moment. Its light has been travelling for roughly
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  Speaker 1: 650 years. Every time you look at that red point,
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  Speaker 1: you are receiving an old message. The star may already
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  Speaker 1: be different from the image you see. And somewhere, far
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  Speaker 1: beyond the reach of your eyes, Betelgeuse could even have
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  Speaker 1: changed dramatically while the older light continues moving toward you.
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  Speaker 1: If it had exploded recently in its own part of
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  Speaker 1: the universe, you would not know yet. The news would
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  Speaker 1: still be travelling. There is something peaceful about that. The
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  Speaker 1: universe does not rush its messages. Light simply travels, across darkness,
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  Speaker 1: across distance, across centuries, and eventually, perhaps long after the
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  Speaker 1: night when you are listening, the message from Betelgeuse's final
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  Speaker 1: transformation may arrive. When it does, Earth should be safe.
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  Speaker 1: Supernovae can be dangerous when they occur extremely close to
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  Speaker 1: a planetary system. Astronomers have found evidence that ancient stellar
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  Speaker 1: explosions may have affected the environment around Earth in the
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  Speaker 1: distant past. Tiny traces of radioactive forms of iron, known
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  Speaker 1: as iron-60, and manganese, known as manganese-53, have been found
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  Speaker 1: in geological material, offering evidence that powerful stellar explosions occurred
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  Speaker 1: relatively close to the solar system in the distant past.
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  Speaker 1: There is also a vast, unusually thin region of space
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  Speaker 1: around our solar system known as the Local Bubble, It
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  Speaker 1: stretches for roughly a thousand light years and is thought
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  Speaker 1: to have been shaped by ancient supernova activity. In other words,
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  Speaker 1: the space around you may already carry the quiet fingerprints
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  Speaker 1: of stars that died millions of years ago. Their explosions
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  Speaker 1: are gone, their light has passed, but traces remain. And
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  Speaker 1: this helps you understand something important about distance. A supernova
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  Speaker 1: is is not automatically dangerous simply because it is powerful.
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  Speaker 1: The distance matters enormously. Betelgeuse is hundreds of light years away.
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  Speaker 1: It is far outside the region where its eventual explosion
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  Speaker 1: would be expected to cause severe damage to Earth. So
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  Speaker 1: when Betelgeuse finally does explode, whenever that may be, you
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  Speaker 1: will not need to hide from it. You will not
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  Speaker 1: need to fear the night sky. Instead, If humanity is
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  Speaker 1: still here to see it, the event could become one
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  Speaker 1: of the most extraordinary sights the night sky has ever offered.
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  Speaker 1: The red star in Orion could suddenly become vastly brighter.
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  Speaker 1: It could remain visible for a long time. Depending on
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  Speaker 1: the actual conditions of the explosion, it could become bright
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  Speaker 1: enough to be seen even during daylight. For a while,
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  Speaker 1: a star hundreds of light-years away could become an unmistakable
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  Speaker 1: light in Earth's sky. Beautiful. distant, and, for Earth, safely
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  Speaker 1: far away. So you can let that image rest quietly now.
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  Speaker 1: Betelgeuse is dying, but it is not rushing toward you.
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  Speaker 1: Its future is written on a timescale far larger than
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  Speaker 1: a human lifetime. Its light is already old when it
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  Speaker 1: reaches you. And somewhere beyond the darkness, the enormous red
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  Speaker 1: star continues slowly toward whatever comes next. For now, there
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  Speaker 1: is no need to know the date. There is only
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  Speaker 1: the quiet red light arriving from far away, carrying with
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  Speaker 1: it a story that began long before you were here.
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  Speaker 1: And beneath that old light, another mystery is waiting. Because
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  Speaker 1: Betelgeuse does not simply brighten and fade once. It moves
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  Speaker 1: through several slow rhythms, some lasting only a little more
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  Speaker 1: than a year, and another lasting for roughly six years,
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  Speaker 1: and one of those rhythms may be telling us something
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  Speaker 1: unexpected about what is moving around the star. There is
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  Speaker 1: another way Betelgeuse has quietly surprised you. It does not
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  Speaker 1: always remain equally bright. Sometimes its red light becomes a
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  Speaker 1: little stronger, sometimes a little softer, and in late 2019
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  Speaker 1: something much more noticeable began to happen. The familiar red
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  Speaker 1: star of Orion started to fade. At first, the change
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  Speaker 1: was easy to overlook. Then it became harder to ignore.
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  Speaker 1: Night after night, Betelgeuse appeared dimmer than people were accustomed
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  Speaker 1: to seeing. Its brightness continued to fall, until by the
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  Speaker 1: beginning of 2020, the star had become dramatically fainter than usual.
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  Speaker 1: At the deepest point of the event, Betelgeuse had lost
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  Speaker 1: roughly two-thirds of its normal visible brightness. For a star
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  Speaker 1: that had remained familiar in the night sky for generations,
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  Speaker 1: this was a remarkable change. And naturally, a quiet question appeared.
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  Speaker 1: Was something happening deep inside the star? Was Betelgeuse finally
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  Speaker 1: beginning the long-awaited process that would end in a supernova?
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  Speaker 1: For a moment, the possibility was difficult to ignore. After all,
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  Speaker 1: Betelgeuse is a massive star, approaching the end of its life.
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  Speaker 1: It is unstable. It changes brightness. It loses material. And eventually,
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  Speaker 1: it will collapse. So, when its red glow suddenly weakened,
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  Speaker 1: it was reasonable to wonder whether the final transformation had
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  Speaker 1: somehow begun. But the universe often has quieter explanations for
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  Speaker 1: dramatic appearances. And in this case, the answer seems to
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  Speaker 1: have been waiting just outside the star itself. Imagine a
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  Speaker 1: small lamp glowing in a dark room. The lamp itself
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  Speaker 1: remains on. Its light continues to shine. But now imagine
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  Speaker 1: that a thin curtain slowly drifts across the front of it.
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  Speaker 1: The lamp has not necessarily become weaker. You are simply
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  Speaker 1: seeing less of its light. Something similar appears to have
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  Speaker 1: happened to Betelgeuse. Astronomers using the Hubble Space Telescope observed
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  Speaker 1: changes in the material surrounding the star during the period
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  Speaker 1: of the Great Dimming. The observations suggested... that a tremendous
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  Speaker 1: amount of hot material had moved outward from the star's surface.
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  Speaker 1: This material travelled away from Betelgeuse and gradually expanded. And
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  Speaker 1: as it expanded, something important happened. It cooled. Warm material
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  Speaker 1: leaving the star entered the colder surroundings of space, and
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  Speaker 1: under the right conditions, some of that material could form dust.
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  Speaker 1: The dust then moved into our line of sight, and
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  Speaker 1: from Earth's the effect was surprisingly simple. Beetlejuice looked darker.
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  Speaker 1: You can imagine that dust as a very thin veil,
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  Speaker 1: not a solid wall, not something that completely covered the star,
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  Speaker 1: just enough material in the right place to hide some
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  Speaker 1: of the light. The source material describes observations in which
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  Speaker 1: material was expelled from Betelgeuse's atmosphere, cooled, and then obscured
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  Speaker 1: part of the star, producing the dramatic dimming seen from Earth.
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  Speaker 1: There is something almost beautiful about this explanation. The star
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  Speaker 1: did not simply switch off. It did not suddenly lose
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  Speaker 1: its ability to shine. Instead, Betelgeuse appears to have briefly
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  Speaker 1: placed a veil across its own light. And this tells
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  Speaker 1: you something important about the outer layers of a red supergiant.
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  Speaker 1: They are not perfectly still. Material can be lifted away.
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  Speaker 1: Gas can move outward. The atmosphere can change. And sometimes
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  Speaker 1: pieces of that atmosphere can travel far enough from the
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  Speaker 1: star to cool and become part of a cloud of dust.
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  Speaker 1: The event was so noticeable because Betelgeuse is normally one
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  Speaker 1: of the brighter stars visible to the naked eye. Its
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  Speaker 1: fading therefore changed the appearance of Orion itself. The familiar
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  Speaker 1: pattern remained in the sky, but one of its brightest
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  Speaker 1: points seemed to be quietly disappearing. Then, gradually, the story
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  Speaker 1: began to reverse. The dust moved, the material dispersed, the
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  Speaker 1: view became clearer, and by April 2020, Betelgeuse had returned
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  Speaker 1: toward its normal brightness. The red star was visible again,
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  Speaker 1: much as it had been before. There was no supernova,
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  Speaker 1: no final collapse, no sudden end, just a temporary change
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  Speaker 1: in how much of its light could reach you. And
• 21:42
  Speaker 1: perhaps that is one of the most useful things to
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  Speaker 1: remember about Betelgeuse. When you look at a distant star,
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  Speaker 1: brightness does not always tell you exactly what is happening
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  Speaker 1: inside it. Sometimes the star itself changes. Sometimes its atmosphere changes.
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  Speaker 1: Sometimes material moves between you and the star, and sometimes
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  Speaker 1: several of these things may be happening at once. The
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  Speaker 1: Great Dimming became an important reminder that Betelgeuse is surrounded
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  Speaker 1: by an enormous, restless atmosphere. You can imagine that atmosphere
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  Speaker 1: extending outward into space, slowly releasing clouds of material, while
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  Speaker 1: the star continues glowing behind them. Nothing about it is static.
• 22:26
  Speaker 1: Even the empty darkness around Betelgeuse can become part of
• 22:30
  Speaker 1: the story. A little gas leaves. It travels outward. It cools.
• 22:35
  Speaker 1: Dust forms. The light becomes softer. Then the cloud drifts away.
• 22:41
  Speaker 1: And the red light returns. Slowly, quietly. Almost as though
• 22:46
  Speaker 1: nothing had happened. But something had happened. The star had
• 22:51
  Speaker 1: shown astronomers a glimpse of how active its outer layers
• 22:55
  Speaker 1: can be. and the Great Dimming was only one of
• 22:58
  Speaker 1: the strange changes Betelgeuse has been showing us. Because when
• 23:02
  Speaker 1: astronomers watched its brightness over much longer periods, they found
• 23:06
  Speaker 1: that the star seemed to follow several different rhythms. One
• 23:09
  Speaker 1: rhythm lasts roughly a little more than a year, another
• 23:13
  Speaker 1: stretches much farther, lasting close to six years, and these
• 23:17
  Speaker 1: rhythms do not always behave like perfectly measured clocks. They overlap,
• 23:23
  Speaker 1: they change. they sometimes become difficult to separate. You can
• 23:27
  Speaker 1: think of them as several very slow breaths happening at once.
• 23:31
  Speaker 1: One breath rises and falls a little faster, another takes
• 23:35
  Speaker 1: much longer, and somewhere underneath them there may be movements
• 23:39
  Speaker 1: that we have not yet fully understood. For many years,
• 23:43
  Speaker 1: astronomers assumed that these brightness changes were connected mainly to
• 23:47
  Speaker 1: the star itself, to its enormous atmosphere, expanding and contracting.
• 23:53
  Speaker 1: rising and falling, brightening and fading. But then the longest
• 23:57
  Speaker 1: rhythm began to attract attention. It lasted around 2,170 days,
• 24:04
  Speaker 1: or roughly six years. And if that rhythm truly belonged
• 24:08
  Speaker 1: to Betelgeuse alone, it might have told us something important
• 24:12
  Speaker 1: about the star's internal structure. Perhaps it was one of
• 24:15
  Speaker 1: the deepest natural rhythms of the star. Perhaps it was
• 24:19
  Speaker 1: an echo of the enormous movements taking place beneath its
• 24:22
  Speaker 1: glowing surface. But there was another possibility. Perhaps the rhythm
• 24:27
  Speaker 1: did not belong entirely to Betelgeuse. Perhaps something else was
• 24:31
  Speaker 1: moving nearby. Something small. Something faint. Something hidden inside the
• 24:37
  Speaker 1: overwhelming red glow of the giant star. And as astronomers
• 24:41
  Speaker 1: followed that slow six-year rhythm, a curious possibility began to emerge.
• 24:47
  Speaker 1: Maybe Betelgeuse was not breathing alone. The red light of
• 24:54
  Speaker 1: Betelgeuse has returned to its familiar brightness, but now you
• 24:58
  Speaker 1: know that the star has never really been still. Even
• 25:01
  Speaker 1: when it appears unchanged to your eyes, enormous movements continue
• 25:06
  Speaker 1: beneath that distant glow. Gas rises, gas falls, material expands,
• 25:13
  Speaker 1: some of it drifts outward. and the brightness of the
• 25:16
  Speaker 1: star changes in response. If you were able to watch
• 25:19
  Speaker 1: Betelgeuse continuously for many years, you would notice that these
• 25:23
  Speaker 1: changes do not follow just one simple rhythm. There is
• 25:27
  Speaker 1: more than one. You might imagine sitting beside a quiet
• 25:31
  Speaker 1: sea at night, watching waves arrive at the shore. One
• 25:35
  Speaker 1: wave comes gently, then another. Some waves are close together,
• 25:40
  Speaker 1: others take much longer to arrive. And if you watched
• 25:43
  Speaker 1: for long enough, you might discover that several different rhythms
• 25:47
  Speaker 1: were passing through the same water at the same time.
• 25:50
  Speaker 1: Betelgeuse is somewhat like this. Its light rises and falls
• 25:54
  Speaker 1: according to several cycles, and astronomers have spent many years
• 25:58
  Speaker 1: trying to understand which movements belong to which rhythm. One
• 26:02
  Speaker 1: of the better-known cycles lasts roughly a little more than
• 26:05
  Speaker 1: 400 days, so a little longer than one Earth year.
• 26:10
  Speaker 1: You could imagine Betelgeuse slowly expanding and contracting through this rhythm,
• 26:15
  Speaker 1: its enormous atmosphere moving outward and inward, changing the way
• 26:19
  Speaker 1: its light reaches you. Then there is another rhythm, a
• 26:23
  Speaker 1: much slower one. It lasts around 2,170 days. That is
• 26:29
  Speaker 1: roughly six years. Six years for one complete rise and fall.
• 26:35
  Speaker 1: Six years for a rhythm to pass quietly through a
• 26:38
  Speaker 1: star that appears to you as nothing more than a
• 26:41
  Speaker 1: tiny red point. The source material describes Betelgeuse as having
• 26:46
  Speaker 1: several incompletely understood brightness cycles, ranging from a few hundred
• 26:51
  Speaker 1: days to approximately 2,170 days. It also notes uncertainty about
• 26:58
  Speaker 1: which of these cycles should be considered the star's deepest
• 27:01
  Speaker 1: or fundamental rhythm. You do not need to remember the numbers.
• 27:06
  Speaker 1: You can simply remember the feeling of them. One rhythm
• 27:09
  Speaker 1: is relatively quick, another is slow, very slow. And beneath
• 27:14
  Speaker 1: both of them, there may be still more subtle movements.
• 27:19
  Speaker 1: This is where the language of astronomy becomes slightly more complicated.
• 27:24
  Speaker 1: Scientists sometimes describe the deepest natural rhythm of a pulsating
• 27:28
  Speaker 1: star as its fundamental rhythm. You can think of this
• 27:32
  Speaker 1: as the star's deepest heartbeat. Not a heartbeat like the
• 27:35
  Speaker 1: one inside your chest, of course, but a slow pattern
• 27:39
  Speaker 1: built into the way the star itself responds to its
• 27:42
  Speaker 1: own gravity and internal energy. And then there can be
• 27:46
  Speaker 1: additional rhythms layered over it. These are sometimes called overtones.
• 27:51
  Speaker 1: You can imagine a musical instrument producing one deep note,
• 27:55
  Speaker 1: while softer notes seem to travel along with it. The
• 27:58
  Speaker 1: notes are different, but they belong to the same instrument.
• 28:02
  Speaker 1: In a similar way, Betelgeuse can show several connected patterns
• 28:06
  Speaker 1: of changing brightness. One rhythm may be deeper, another may
• 28:10
  Speaker 1: be a softer echo, another may come from a different
• 28:13
  Speaker 1: physical process entirely, and the difficulty is that astronomers are
• 28:18
  Speaker 1: still working out which is which. This matters because the
• 28:21
  Speaker 1: fundamental rhythm may tell us something about the star's internal condition.
• 28:27
  Speaker 1: If one of these cycles were directly connected to the
• 28:30
  Speaker 1: deepest stage of Betelgeuse's evolution, it could potentially offer clues
• 28:35
  Speaker 1: about how close the star is to its eventual collapse.
• 28:39
  Speaker 1: But if you mistake one rhythm for another, you might
• 28:42
  Speaker 1: think you are reading the star's internal clock, when you
• 28:45
  Speaker 1: are actually watching something happening much closer to its surface.
• 28:50
  Speaker 1: That is one reason Betelgeuse is so fascinating. The star
• 28:54
  Speaker 1: does not hand us a single clear signal. It sends
• 28:57
  Speaker 1: several signals at once. And because you are watching from
• 29:01
  Speaker 1: 650 light-years away, All of those signals arrive together as
• 29:06
  Speaker 1: changes in a tiny point of light. Imagine listening to
• 29:10
  Speaker 1: several distant bells ringing through the night. One rings once
• 29:15
  Speaker 1: every year. Another rings once every several years. Others may
• 29:19
  Speaker 1: ring irregularly. From very far away their sounds begin to overlap.
• 29:25
  Speaker 1: You can hear that something is happening. You can measure
• 29:27
  Speaker 1: the timing. But separating every bell from every other bell
• 29:32
  Speaker 1: becomes surprisingly difficult. Betelgeuse creates something similar with light, and
• 29:38
  Speaker 1: there are clues that the star's rhythms have changed in
• 29:40
  Speaker 1: ways that make the picture even more complicated. Back in 2009,
• 29:46
  Speaker 1: for example, observations indicated that Betelgeuse had contracted in size
• 29:51
  Speaker 1: by roughly 15%. That did not mean the star was
• 29:55
  Speaker 1: suddenly collapsing toward a supernova. It was another glimpse of
• 29:59
  Speaker 1: how dramatically the outer layers of this enormous star can change.
• 30:04
  Speaker 1: A star can become smaller, then larger, brighter, then dimmer,
• 30:09
  Speaker 1: and still remain essentially the same star. This is why
• 30:13
  Speaker 1: the Great Dimming of 2019 became so difficult to interpret.
• 30:18
  Speaker 1: The dimming happened against a background of many other natural variations.
• 30:23
  Speaker 1: The star was already known to pulsate. It was already
• 30:26
  Speaker 1: known to lose material. it already possessed several brightness cycles.
• 30:32
  Speaker 1: Then suddenly, a cloud of material crossed our view and
• 30:36
  Speaker 1: the star became much darker. For a moment, it was
• 30:39
  Speaker 1: difficult to know which rhythm we were seeing. Was it
• 30:43
  Speaker 1: the star itself? Was it material moving around the star?
• 30:47
  Speaker 1: Was it one of the known cycles? Or was it
• 30:49
  Speaker 1: something entirely different? And now, after all of these slow changes,
• 30:55
  Speaker 1: we can return to that six-year rhythm. the one lasting
• 30:59
  Speaker 1: approximately 2,170 days. For a long time, it was tempting
• 31:05
  Speaker 1: to imagine that this might be the most important rhythm
• 31:07
  Speaker 1: of all. Perhaps it was the fundamental rhythm. Perhaps it
• 31:11
  Speaker 1: was connected to the final stages of Betelgeuse's life. Perhaps,
• 31:16
  Speaker 1: if astronomers understood it correctly, it might even help narrow
• 31:20
  Speaker 1: down the time remaining before the star becomes a supernova.
• 31:24
  Speaker 1: But then something unexpected began to appear. The long rhythm
• 31:29
  Speaker 1: seemed to have another possible explanation. Not another movement inside Betelgeuse.
• 31:35
  Speaker 1: Not another pulse of its enormous atmosphere. But another star.
• 31:40
  Speaker 1: A smaller star. A faint companion moving quietly around the giant.
• 31:45
  Speaker 1: The idea had existed for more than a century. Astronomers
• 31:48
  Speaker 1: had wondered whether Betelgeuse might be part of a pair,
• 31:52
  Speaker 1: bound together by gravity. But proving that was extremely difficult.
• 31:57
  Speaker 1: Betelgeuse itself was too restless. Its brightness changed, its atmosphere shifted,
• 32:03
  Speaker 1: its surface moved. Trying to detect the tiny influence of
• 32:07
  Speaker 1: another star was like trying to notice the gentle pull
• 32:10
  Speaker 1: of a small boat while standing inside a much larger
• 32:14
  Speaker 1: moving ship. Yet after the Great Dimming, attention returned to
• 32:18
  Speaker 1: the problem, and two independent research teams began studying the
• 32:22
  Speaker 1: star's long-term motion. They found something intriguing. Beetlejuice appeared to
• 32:28
  Speaker 1: make a tiny repeated movement from side to side, not
• 32:32
  Speaker 1: enough for your eyes to see, not enough to notice
• 32:35
  Speaker 1: in the night sky, just a subtle shift in its
• 32:38
  Speaker 1: position over time, as though something unseen were gently tugging
• 32:43
  Speaker 1: on it, and that tiny movement appeared to follow the
• 32:46
  Speaker 1: same long rhythm, the six-year rhythm, the 2,170-day rhythm, Perhaps
• 32:53
  Speaker 1: then the deepest mystery was not hidden entirely inside Betelgeuse.
• 32:58
  Speaker 1: Perhaps part of the answer was moving quietly beside it.
• 33:02
  Speaker 1: And if that were true, the strange changes in the
• 33:04
  Speaker 1: red supergiant would no longer belong to one star alone.
• 33:09
  Speaker 1: They would belong to a slow gravitational relationship between two
• 33:13
  Speaker 1: distant suns. A giant red star, and a much smaller companion,
• 33:19
  Speaker 1: almost hidden within its overwhelming light. For now, you can
• 33:23
  Speaker 1: let that possibility remain just beyond the edge of the image,
• 33:28
  Speaker 1: a faint presence beside the red giant, moving slowly, almost invisible,
• 33:34
  Speaker 1: and waiting for us to look more carefully. There is
• 33:39
  Speaker 1: something almost impossible about trying to see a small star
• 33:43
  Speaker 1: beside Betelgeuse. You can imagine the two of them together
• 33:46
  Speaker 1: in the darkness, one enormous and intensely bright, the other
• 33:51
  Speaker 1: much smaller and almost completely hidden in its glow. From
• 33:55
  Speaker 1: a great distance they would not look like two separate stars.
• 33:59
  Speaker 1: They would look like one, a single red point of light.
• 34:03
  Speaker 1: And yet, if the evidence is correct, there may be
• 34:06
  Speaker 1: another star quietly moving around Betelgeuse, a small companion, a
• 34:11
  Speaker 1: second presence in the darkness. Astronomers have wondered about such
• 34:16
  Speaker 1: a companion for more than a century. The idea is
• 34:19
  Speaker 1: not entirely new. For generations, researchers have noticed that Betelgeuse
• 34:24
  Speaker 1: behaves in ways that are difficult to explain using the
• 34:27
  Speaker 1: star alone. Its brightness changes, its position seems to shift slightly,
• 34:33
  Speaker 1: its long rhythm repeats. And sometimes, the movements appear almost
• 34:38
  Speaker 1: too organised to be explained simply by the enormous turbulence
• 34:41
  Speaker 1: of the red supergiant. The possibility of another star offers
• 34:46
  Speaker 1: a remarkably simple image. Imagine a holding a very heavy
• 34:50
  Speaker 1: lantern while a much smaller object slowly circles around it.
• 34:55
  Speaker 1: The smaller object is moving, but the larger lantern does
• 34:58
  Speaker 1: not remain perfectly still. Instead, both objects move around a
• 35:03
  Speaker 1: shared centre of gravity. The movement of the larger object
• 35:07
  Speaker 1: is tiny, so tiny that you would never notice it
• 35:10
  Speaker 1: with your eyes. But if you watched carefully enough and
• 35:14
  Speaker 1: measured its position over many years, you might begin to
• 35:17
  Speaker 1: see the patterns. Something similar may be happening with Betelgeuse.
• 35:21
  Speaker 1: The proposed companion is sometimes called Betelbuddy, while the source
• 35:26
  Speaker 1: material identifies the star as Siwaha. You can simply think
• 35:31
  Speaker 1: of Siwaha as the faint companion, a much smaller star
• 35:35
  Speaker 1: orbiting one of the most recognisable red supergiants in the sky.
• 35:40
  Speaker 1: The evidence described in the source material suggests that Siwaha
• 35:44
  Speaker 1: may have a mass roughly comparable to that of our Sun.
• 35:48
  Speaker 1: Its orbit may extend across a distance comparable to the
• 35:52
  Speaker 1: outer regions of our own solar system. Compared with Betelgeuse,
• 35:56
  Speaker 1: this companion would be tiny, and that difference creates the
• 36:00
  Speaker 1: central observational problem. Betelgeuse is so bright that Siwaha can
• 36:05
  Speaker 1: almost disappear inside its light. Imagine trying to see a
• 36:09
  Speaker 1: candle flame positioned directly beside a giant furnace. The candle
• 36:15
  Speaker 1: may be shining. It may be perfectly visible in isolation,
• 36:19
  Speaker 1: but beside the furnace its light becomes almost impossible to separate.
• 36:24
  Speaker 1: That is what astronomers are dealing with. The proposed companion
• 36:28
  Speaker 1: is several magnitudes fainter than Betelgeuse. You do not need
• 36:32
  Speaker 1: to remember the technical meaning of a magnitude. It is
• 36:36
  Speaker 1: enough to imagine an enormous difference in brightness. Betelgeuse fills
• 36:40
  Speaker 1: the view with red light, Siwaha whispers. And so, Rather
• 36:45
  Speaker 1: than simply taking an ordinary photograph and looking for a
• 36:49
  Speaker 1: second point of light, astronomers have needed much more careful observations.
• 36:54
  Speaker 1: One of the important observations came from Gemini North, a
• 36:58
  Speaker 1: large telescope located in Hawaii. The telescope can use a
• 37:02
  Speaker 1: technique called speckle imaging. The name sounds technical, but the
• 37:07
  Speaker 1: idea is gentle. Instead of taking one long photograph through
• 37:11
  Speaker 1: Earth's constantly moving atmosphere, astronomers can collect thousands of extremely
• 37:16
  Speaker 1: short images. Each tiny image captures a slightly different moment.
• 37:21
  Speaker 1: The atmosphere distorts the view a little, but when many
• 37:24
  Speaker 1: of those brief glimpses are carefully combined, the final result
• 37:29
  Speaker 1: can reveal details that would otherwise remain hidden. It is
• 37:33
  Speaker 1: almost like watching thousands of tiny ripples on a pond,
• 37:37
  Speaker 1: and slowly reconstructing the shape of something beneath the surface.
• 37:42
  Speaker 1: With Gemini North, Astronomers looked for the companion when it
• 37:45
  Speaker 1: was expected to be at one of its more favourable
• 37:47
  Speaker 1: positions relative to Betelgeuse. The reason for choosing this moment
• 37:52
  Speaker 1: was simple. If Siwaha moves around Betelgeuse, there are times
• 37:57
  Speaker 1: when the two stars appear closer together in our sky.
• 38:01
  Speaker 1: At other times they separate slightly. The farther apart they appear,
• 38:05
  Speaker 1: the easier it becomes to distinguish the faint companion from
• 38:09
  Speaker 1: the overwhelming glow of Betelgeuse. And something interesting appeared. A
• 38:14
  Speaker 1: faint source of light was detected close to where the
• 38:17
  Speaker 1: companion was expected to be. It was extremely difficult to see.
• 38:22
  Speaker 1: It was close to the limits of what the observations
• 38:24
  Speaker 1: could resolve. But its location was intriguing. Its position was
• 38:29
  Speaker 1: consistent with the predicted orbit. And when astronomers compared the
• 38:33
  Speaker 1: observation with earlier measurements, the pieces seemed to fit together.
• 38:38
  Speaker 1: Not perfectly. Not conclusively. but enough to keep the possibility alive.
• 38:44
  Speaker 1: This distinction matters. The companion has not been presented as
• 38:48
  Speaker 1: an absolutely confirmed fact. Instead, the evidence is becoming stronger.
• 38:53
  Speaker 1: A faint object has been detected. Its location is consistent
• 38:58
  Speaker 1: with the proposed companion. Its movement appears compatible with the
• 39:02
  Speaker 1: long-term changes observed in Betelgeuse. And there are further opportunities
• 39:07
  Speaker 1: to test the idea. Around the year 2027, Siwarha is
• 39:12
  Speaker 1: expected to reach another favourable point in its orbit, when
• 39:16
  Speaker 1: the apparent separation between the two stars should again make
• 39:20
  Speaker 1: the companion easier to distinguish. That future observation could become
• 39:24
  Speaker 1: especially valuable. If the faint object appears where the orbital
• 39:28
  Speaker 1: model predicts, and continues moving in the expected way, confidence
• 39:33
  Speaker 1: in the companion will increase, and if it does not
• 39:36
  Speaker 1: appear where expected, the mystery will become more complicated again.
• 39:41
  Speaker 1: For now, you can simply imagine the two stars moving
• 39:44
  Speaker 1: through darkness, Betelgeuse, Enormous and Red. Siwaha, small and faint,
• 39:51
  Speaker 1: neither rushing, neither making a sound, bound together by gravity
• 39:56
  Speaker 1: across an immense distance. And suddenly, that strange six-year rhythm
• 40:01
  Speaker 1: begins to look different. Perhaps it is not simply Betelgeuse
• 40:05
  Speaker 1: breathing in and out. Perhaps part of that rhythm comes
• 40:09
  Speaker 1: from the slow orbital dance between the two stars. The
• 40:13
  Speaker 1: source material describes independent research suggesting that the approximately 2,170-day
• 40:20
  Speaker 1: brightness cycle could be connected to the gravitational influence of
• 40:24
  Speaker 1: the companion, meaning that the cycle should not necessarily be
• 40:28
  Speaker 1: treated as a direct countdown toward Betelgeuse's supernova. This is
• 40:33
  Speaker 1: an important change in perspective. The rhythm that once seemed
• 40:37
  Speaker 1: like a possible internal clock may instead be a sign
• 40:40
  Speaker 1: of companionship, a movement caused not by Betelgeuse alone but
• 40:46
  Speaker 1: by the quiet relationship between two stars. And there may
• 40:50
  Speaker 1: be another clue. Recent observations have suggested the possibility of
• 40:54
  Speaker 1: a faint wake of material associated with the companion as
• 40:59
  Speaker 1: it moves through the extended atmosphere around Betelgeuse. You can
• 41:03
  Speaker 1: imagine a small boat moving through still water. The boat
• 41:07
  Speaker 1: is tiny. The water is enormous. Yet behind the boat
• 41:11
  Speaker 1: a faint trail remains. If something similar is happening around Betelgeuse,
• 41:17
  Speaker 1: Siwaha may not simply be passing through empty space. It
• 41:21
  Speaker 1: may be moving through the enormous outer material surrounding the
• 41:24
  Speaker 1: red supergiant, leaving behind a subtle disturbance, a small star,
• 41:30
  Speaker 1: a vast atmosphere, a faint trail, and a rhythm that
• 41:35
  Speaker 1: returns again and again. None of these clues alone tells
• 41:39
  Speaker 1: the whole story, but together they offer something beautiful. They
• 41:44
  Speaker 1: suggest that Betelgeuse may not be an isolated giant slowly
• 41:48
  Speaker 1: changing by itself. It may be part of a much larger,
• 41:53
  Speaker 1: quieter relationship. And while that possibility helps explain one of
• 41:57
  Speaker 1: its strange rhythms, it also opens another question. Because Betelgeuse
• 42:03
  Speaker 1: appears to be doing something else that is surprisingly difficult
• 42:06
  Speaker 1: to explain. It seems to be rotating much faster than
• 42:10
  Speaker 1: a star of its enormous size should. And if that
• 42:13
  Speaker 1: apparent rotation is real, something must have given the giant
• 42:17
  Speaker 1: star an unexpected amount of spin. Perhaps, long ago, another
• 42:23
  Speaker 1: companion came too close. Perhaps Betelgeuse gained some of its
• 42:27
  Speaker 1: motion from a star it eventually consumed. Or perhaps the
• 42:31
  Speaker 1: star is not rotating nearly as quickly as it appears.
• 42:35
  Speaker 1: The answer may be hidden in the restless surface itself.
• 42:39
  Speaker 1: And for now... That faint companion remains beside the red giant,
• 42:44
  Speaker 1: almost invisible, slowly moving through the darkness, while astronomers wait
• 42:49
  Speaker 1: for the next quiet opportunity to see whether the two
• 42:53
  Speaker 1: really belong together. There is another quiet mystery waiting beneath
• 42:59
  Speaker 1: the red glow of Betelgeuse. You have already imagined the
• 43:03
  Speaker 1: enormous star rising and falling, its atmosphere moving in great
• 43:08
  Speaker 1: slow currents. its faint companion perhaps circling nearby. But now
• 43:14
  Speaker 1: imagine something even simpler. Imagine that Betelgeuse is turning, very
• 43:19
  Speaker 1: slowly perhaps, but turning nonetheless. At first, this may not
• 43:24
  Speaker 1: sound particularly strange. Stars rotate, our own sun rotates, planets rotate,
• 43:31
  Speaker 1: even galaxies turn. So why should Betelgeuse's rotation be mysterious?
• 43:37
  Speaker 1: The answer is hidden, in its enormous size. Betelgeuse is
• 43:41
  Speaker 1: so large that you might expect its outer layers to
• 43:44
  Speaker 1: move rather slowly as the star turns. And yet, when
• 43:48
  Speaker 1: astronomers examined the light coming from different parts of its surface,
• 43:53
  Speaker 1: they found a pattern that appeared to suggest surprisingly rapid rotation.
• 43:58
  Speaker 1: To understand how they could possibly know this, you can
• 44:01
  Speaker 1: begin with something much closer to you. Sound. Imagine standing
• 44:06
  Speaker 1: beside a quiet road at night. Far away, you hear
• 44:10
  Speaker 1: a vehicle approaching. The sound seems to change as it
• 44:13
  Speaker 1: moves toward you. Then, after the vehicle passes, the sound
• 44:18
  Speaker 1: changes again as it travels away. Nothing about the vehicle's
• 44:22
  Speaker 1: engine has suddenly transformed. The change comes from motion. The
• 44:27
  Speaker 1: waves reaching your ears are being compressed slightly as the
• 44:31
  Speaker 1: source approaches and stretched slightly as it moves away. Light
• 44:36
  Speaker 1: behaves in a similar way. The effect is called the
• 44:40
  Speaker 1: Doppler effect. You do not need to remember the name.
• 44:44
  Speaker 1: You can simply remember the idea. Movement can leave a
• 44:47
  Speaker 1: tiny signature in the light. If one side of a
• 44:50
  Speaker 1: rotating star is moving toward you, the light from that
• 44:54
  Speaker 1: side shifts very slightly toward the blue end of the
• 44:57
  Speaker 1: visible spectrum. If the opposite side is moving away from you,
• 45:02
  Speaker 1: its light shifts slightly toward the red end. So, in principle,
• 45:07
  Speaker 1: By carefully examining the light from different regions of a
• 45:10
  Speaker 1: distant star, astronomers can look for evidence that one side
• 45:14
  Speaker 1: is approaching while the other is receding. It is almost
• 45:18
  Speaker 1: as if the star were whispering its movement through its light.
• 45:22
  Speaker 1: Betelgeuse has provided just such a whisper. Observations using the
• 45:27
  Speaker 1: Atacama Large Millimetre Array, often shortened to ALMA, have been
• 45:32
  Speaker 1: interpreted as showing a velocity pattern consistent with rotation corresponding
• 45:38
  Speaker 1: to a surface speed of roughly 5 km per second.
• 45:42
  Speaker 1: 5 km per second. You do not need to hold
• 45:45
  Speaker 1: on to that number. What matters is that the motion
• 45:48
  Speaker 1: appears surprisingly fast for a star as enormous as Betelgeuse.
• 45:53
  Speaker 1: Because when a star becomes very large, its rotation should
• 45:57
  Speaker 1: generally become slower. You can imagine a figure skater standing
• 46:01
  Speaker 1: on ice. When the skater pulls their arms close to
• 46:04
  Speaker 1: the body, they can spin more quickly. but when they
• 46:07
  Speaker 1: stretch their arms outward, the rotation slows. The same basic
• 46:11
  Speaker 1: idea applies to the way a star's size influences its rotation.
• 46:16
  Speaker 1: As something expands, its spin can slow, and Betelgeuse has
• 46:21
  Speaker 1: expanded enormously. Its outer atmosphere reaches across a scale that
• 46:25
  Speaker 1: is difficult to imagine, so if the star really is
• 46:29
  Speaker 1: rotating as quickly as the observations appear to suggest, something
• 46:33
  Speaker 1: unusual must have happened to give it that motion. one
• 46:37
  Speaker 1: possibility reaches back into the star's past. Perhaps Betelgeuse once
• 46:41
  Speaker 1: had another companion. Not necessarily Siwaha, as we see the
• 46:46
  Speaker 1: proposed companion today, but another star that interacted with Betelgeuse
• 46:51
  Speaker 1: much more closely. Over time, gravity could have pulled material
• 46:55
  Speaker 1: from that companion into the growing red supergiant, and the
• 47:00
  Speaker 1: material arriving from the companion would have carried motion with it,
• 47:05
  Speaker 1: a little like pouring water into a slowly turning bowl.
• 47:08
  Speaker 1: The incoming material would not simply add mass, it could
• 47:12
  Speaker 1: also add spin. Eventually, the smaller companion might have been consumed,
• 47:18
  Speaker 1: the red supergiant would remain, and some of the companion's
• 47:22
  Speaker 1: motion could have been transferred into Betelgeuse. This is sometimes
• 47:26
  Speaker 1: described as a stellar merger or stellar cannibalism, but again,
• 47:32
  Speaker 1: you do not need to keep the technical words. The
• 47:35
  Speaker 1: image is enough. One star feeds on another. The smaller
• 47:39
  Speaker 1: star disappears into the larger one, and the larger star
• 47:43
  Speaker 1: begins turning a little faster. It is an elegant possibility.
• 47:47
  Speaker 1: It could help explain why Betelgeuse seems to rotate so
• 47:50
  Speaker 1: quickly despite its enormous size. It also connects beautifully with
• 47:55
  Speaker 1: the broader mystery of companions. Perhaps Betelgeuse has not always
• 47:59
  Speaker 1: lived alone. Perhaps its history has been shaped by more
• 48:03
  Speaker 1: than one neighbouring star. Maybe an earlier companion changed its spin,
• 48:08
  Speaker 1: and perhaps the faint siwaha moving around it today is
• 48:12
  Speaker 1: part of a much longer story of companionship, interaction, and
• 48:16
  Speaker 1: gravitational influence. But there is a problem, a very important problem.
• 48:22
  Speaker 1: What if Betelgeuse is not actually rotating as quickly as
• 48:26
  Speaker 1: it appears? What if the pattern in its light is
• 48:29
  Speaker 1: being produced by something else? Remember what you imagined earlier.
• 48:33
  Speaker 1: The surface of Betelgeuse is not smooth. It is not
• 48:37
  Speaker 1: a solid red ball. It is an enormous, turbulent atmosphere
• 48:42
  Speaker 1: filled with rising and falling regions of gas. Some regions
• 48:46
  Speaker 1: are moving toward you. Others are moving away. Some are hotter.
• 48:51
  Speaker 1: Others are cooler. Some shine more brightly. Others appear darker.
• 48:56
  Speaker 1: And these regions can be enormous. If those movements are
• 49:00
  Speaker 1: large enough, They can create patterns in the light that
• 49:03
  Speaker 1: resemble rotation. That possibility changes everything. Because the observation may
• 49:10
  Speaker 1: not be telling you Betelgeuse is spinning quickly. It may
• 49:13
  Speaker 1: instead be telling you parts of Betelgeuse's surface are moving quickly.
• 49:19
  Speaker 1: Those are not the same. thing. Imagine looking at a
• 49:22
  Speaker 1: vast field of tall grass from very far away. A
• 49:26
  Speaker 1: breeze passes across it. One region bends toward you, another
• 49:31
  Speaker 1: bends away. The moving pattern might look like something travelling
• 49:35
  Speaker 1: across the field in one smooth direction, But the field
• 49:38
  Speaker 1: itself is not turning. It is simply moving in many
• 49:42
  Speaker 1: places at once. Betelgeuse may be doing something similar. And
• 49:47
  Speaker 1: this is where the mystery becomes especially interesting. The same
• 49:51
  Speaker 1: enormous convective movements that make the star's surface restless may
• 49:56
  Speaker 1: also be creating the appearance of rapid rotation. If so,
• 50:01
  Speaker 1: the star may not need an unusual history of stellar
• 50:04
  Speaker 1: cannibalism to explain its apparent spin. The explanation could be
• 50:09
  Speaker 1: much closer to the surface, not a hidden event from
• 50:12
  Speaker 1: millions of years ago, not a dramatic encounter with another star,
• 50:17
  Speaker 1: just enormous bubbles of gas, rising and falling beneath the
• 50:21
  Speaker 1: red glow. For now, both possibilities remain important. Perhaps Betelgeuse
• 50:28
  Speaker 1: really does rotate unusually quickly. Perhaps it gained that motion
• 50:32
  Speaker 1: from a companion long ago. Or perhaps the star is
• 50:36
  Speaker 1: moving in a much more complicated way and our distant
• 50:39
  Speaker 1: observations are turning that complexity into the appearance of rotation.
• 50:45
  Speaker 1: The answer is still being investigated and somewhere in the
• 50:49
  Speaker 1: darkness the enormous red star continues to move. Whether it
• 50:54
  Speaker 1: is truly spinning or simply churning the light reaching you
• 50:58
  Speaker 1: carries only a faint impression of that motion and perhaps
• 51:02
  Speaker 1: the most fascinating possibility is that the apparent turning of
• 51:06
  Speaker 1: the entire star may actually be the movement of enormous
• 51:11
  Speaker 1: bubbles on its surface. You have already imagined Betelgeuse turning
• 51:17
  Speaker 1: slowly through the darkness, one side moving toward you, the
• 51:22
  Speaker 1: other side moving away, a faint difference in the light
• 51:26
  Speaker 1: from each side, suggesting that the enormous star may be
• 51:30
  Speaker 1: spinning at a surprisingly high speed. It is a beautiful explanation. Simple,
• 51:36
  Speaker 1: almost too simple, because there is another possibility. Perhaps Betelgeuse
• 51:41
  Speaker 1: is not turning rapidly at all. Perhaps what looks like
• 51:44
  Speaker 1: rotation is something much more restless, much more complicated, and
• 51:48
  Speaker 1: in a strange way, much more ordinary. The surface may
• 51:52
  Speaker 1: simply be moving, not in one smooth direction, but everywhere.
• 51:58
  Speaker 1: Imagine looking down at a vast ocean from high above.
• 52:02
  Speaker 1: From a great distance, the surface might appear almost smooth.
• 52:07
  Speaker 1: But as you came closer, you would begin to see
• 52:10
  Speaker 1: countless movements, small waves, larger waves, currents, foam, rising water,
• 52:19
  Speaker 1: falling water. The surface would no longer look like one
• 52:23
  Speaker 1: simple motion. It would become a constantly changing pattern. Betelgeuse
• 52:28
  Speaker 1: may be something like that, except its ocean is made
• 52:31
  Speaker 1: of extremely hot gas. and its waves are enormous. Deep
• 52:36
  Speaker 1: inside the star, heat is constantly trying to move outward.
• 52:40
  Speaker 1: Hot material rises. As it reaches higher regions, it cools.
• 52:45
  Speaker 1: Then cooler material sinks again. The process repeats, slowly, continuously,
• 52:52
  Speaker 1: across an enormous stellar surface. Astronomers call this convection. And
• 52:58
  Speaker 1: in a red supergiant like Betelgeuse, Convection can become extraordinarily large.
• 53:04
  Speaker 1: The simulations described in the source material show bubbles of
• 53:08
  Speaker 1: moving gas that can reach around 100 million kilometres across,
• 53:13
  Speaker 1: covering a substantial fraction of the star's visible surface. 100
• 53:18
  Speaker 1: million kilometres. You do not need to picture the exact number.
• 53:22
  Speaker 1: Just imagine a single region of hot gas large enough
• 53:26
  Speaker 1: to dwarf the distances between many familiar worlds. And there
• 53:30
  Speaker 1: may be several of these enormous regions moving at once.
• 53:34
  Speaker 1: One rises, another sinks, one drifts toward you, another moves away.
• 53:40
  Speaker 1: Some are brighter, some are darker, some remain for a
• 53:44
  Speaker 1: while before changing shape. The surface becomes a vast, glowing mosaic.
• 53:50
  Speaker 1: And this creates a problem, because moving gas changes the
• 53:54
  Speaker 1: light we receive. You already encountered the Doppler effect when
• 53:58
  Speaker 1: we imagined a passing siren, but now, instead of one
• 54:02
  Speaker 1: vehicle moving towards you and then away, imagine thousands of
• 54:06
  Speaker 1: enormous regions of gas moving in different directions across the
• 54:10
  Speaker 1: surface of a star. Each region carries its own tiny
• 54:15
  Speaker 1: shift in the frequency of light. Some light becomes slightly bluer,
• 54:20
  Speaker 1: some becomes slightly redder, and some remains closer to the
• 54:23
  Speaker 1: star's ordinary colour. If you could see every individual region clearly,
• 54:29
  Speaker 1: the pattern might look chaotic. A blue patch here. A
• 54:33
  Speaker 1: red patch there. Another blue patch somewhere else. A little
• 54:37
  Speaker 1: red region moving beneath it. A changing landscape of light.
• 54:42
  Speaker 1: That would not look much like rotation. A rotating star
• 54:45
  Speaker 1: should create something more orderly. One side would generally be
• 54:49
  Speaker 1: moving toward you. The opposite side would generally be moving away.
• 54:54
  Speaker 1: The result would be a smooth transition, bluer light on
• 54:58
  Speaker 1: one side, then a gradual change, then redder light on
• 55:02
  Speaker 1: the other, a little like a gradient painted across the surface. So,
• 55:07
  Speaker 1: if astronomers see a smooth gradient, rotation seems like the
• 55:11
  Speaker 1: obvious answer. And this is where the distance to Betelgeuse
• 55:15
  Speaker 1: becomes important, because Betelgeuse is enormous, but it is also
• 55:20
  Speaker 1: hundreds of light-years away. From Earth, Even a star this
• 55:24
  Speaker 1: large is still incredibly small in our sky. The telescopes
• 55:28
  Speaker 1: do not receive a perfect high-definition photograph of every bubbling region. Instead,
• 55:35
  Speaker 1: the image is blurred. Many individual regions of the surface
• 55:39
  Speaker 1: become mixed together. The separate bubbles overlap. Their light blends.
• 55:44
  Speaker 1: Their movements blend. And the beautiful complexity of the surface
• 55:48
  Speaker 1: becomes compressed into a much simpler image. Imagine standing on
• 55:53
  Speaker 1: a hill several kilometres away from a field covered in
• 55:57
  Speaker 1: tiny flags. Some flags are blue, some are red, some
• 56:01
  Speaker 1: are moving left, others are moving right. From close up,
• 56:06
  Speaker 1: you could clearly distinguish them. But from far away, the
• 56:09
  Speaker 1: field would blur into a general pattern of colour. A
• 56:13
  Speaker 1: patchwork could begin to resemble a gradient. And that may
• 56:16
  Speaker 1: be exactly what is happening with Betelgeuse. Researchers have created
• 56:20
  Speaker 1: simulations of the star's turbulent surface and then viewed those
• 56:25
  Speaker 1: simulated surfaces at the limited resolution available to astronomers. The
• 56:30
  Speaker 1: result is surprisingly important. The turbulent patterns can be mistaken
• 56:35
  Speaker 1: for a smooth rotational pattern in about 90% of the
• 56:39
  Speaker 1: simulations described in the source material. 90%. That does not
• 56:45
  Speaker 1: mean that Betelgeuse definitely is not rotating. It means something
• 56:49
  Speaker 1: more subtle. It means that turbulence is capable of creating
• 56:53
  Speaker 1: an appearance that looks remarkably similar to rotation when the
• 56:57
  Speaker 1: star is viewed from far away with limited resolution. So
• 57:01
  Speaker 1: perhaps the telescope did not make a mistake. Perhaps the
• 57:05
  Speaker 1: astronomers did not make a mistake. Perhaps the light itself
• 57:09
  Speaker 1: was telling the truth. The problem may simply be that
• 57:13
  Speaker 1: there was more than one way to interpret what that
• 57:15
  Speaker 1: light meant. The star could be rotating. or the star
• 57:19
  Speaker 1: could be boiling, or, perhaps, some combination of both could
• 57:24
  Speaker 1: be happening, and there is something wonderfully strange about that possibility.
• 57:29
  Speaker 1: The very thing that makes Betelgeuse so enormous may also
• 57:32
  Speaker 1: make it difficult to understand. Its giant size creates enormous convection,
• 57:38
  Speaker 1: its distance blurs those movements together, and that blur can
• 57:42
  Speaker 1: transform a complicated surface into a deceptively simple pattern. A
• 57:47
  Speaker 1: moving patch can become part of a gradient. Several rising
• 57:51
  Speaker 1: bubbles can resemble one turning surface. A turbulent star can
• 57:55
  Speaker 1: appear to spin. You can imagine standing far away from
• 57:59
  Speaker 1: a candle in a dark room. At first you see
• 58:02
  Speaker 1: one small point of light. Then the air moves. The
• 58:06
  Speaker 1: flame bends. It flickers. The shape changes. But from far
• 58:11
  Speaker 1: enough away, all those movements disappear into a single shimmering glow.
• 58:16
  Speaker 1: Betelgeuse is doing something similar, only on a scale that
• 58:20
  Speaker 1: is almost impossible to imagine. Its atmosphere is moving, its
• 58:25
  Speaker 1: bubbles are rising and falling, its light is changing. And
• 58:29
  Speaker 1: by the time that light reaches Earth, the individual motions
• 58:33
  Speaker 1: have been softened together by distance. This is why higher
• 58:37
  Speaker 1: resolution observations matter so much. If astronomers can separate more
• 58:42
  Speaker 1: of the individual regions on Betelgeuse's surface, they may be
• 58:47
  Speaker 1: able to determine whether the pattern really behaves like a
• 58:50
  Speaker 1: rotating star, or whether it breaks apart into the irregular
• 58:54
  Speaker 1: mosaic expected from convection. The answer could change our understanding
• 58:58
  Speaker 1: of Betelgeuse's history. If the rapid rotation is real, perhaps
• 59:03
  Speaker 1: a companion once transferred its motion to the red giant.
• 59:07
  Speaker 1: If the apparent rotation is mostly an illusion, created by convection,
• 59:12
  Speaker 1: then Betelgeuse may not require such an unusual explanation. Its
• 59:16
  Speaker 1: surface may simply be doing what the surface of a
• 59:19
  Speaker 1: massive red supergiant naturally does, rising, falling, changing, boiling beneath
• 59:26
  Speaker 1: its own enormous warmth. And perhaps... This is the quietest
• 59:31
  Speaker 1: answer of all. Betelgeuse may not be breaking the rules.
• 59:35
  Speaker 1: It may simply be moving in more ways than we
• 59:37
  Speaker 1: can easily see. Far away, the red giant continues to glow.
• 59:42
  Speaker 1: Somewhere beneath that distant light, enormous bubbles rise through its atmosphere.
• 59:47
  Speaker 1: Some move toward you, some move away. And by the
• 59:51
  Speaker 1: time their light reaches your eyes, all of those motions
• 59:54
  Speaker 1: have become one soft red point in the night. There
• 1:00:00
  Speaker 1: is something quietly comforting about a mystery that does not
• 1:00:03
  Speaker 1: need to be solved tonight. Betelgeuse has given astronomers many clues.
• 1:00:09
  Speaker 1: But the clues do not form a perfectly straight path.
• 1:00:12
  Speaker 1: They overlap. They sometimes point in different directions. And sometimes,
• 1:00:18
  Speaker 1: what first appears to be one answer becomes another question.
• 1:00:22
  Speaker 1: You have already seen the red giant dim. You have
• 1:00:26
  Speaker 1: watched clouds of material drift across its face. You have
• 1:00:30
  Speaker 1: followed its slow rhythms. You have imagined the possibility of
• 1:00:34
  Speaker 1: a small companion moving quietly around it. And you have
• 1:00:38
  Speaker 1: watched enormous bubbles of gas rise and fall across its surface,
• 1:00:43
  Speaker 1: perhaps creating the illusion that the whole star is turning.
• 1:00:47
  Speaker 1: When you place all of these pieces together, Betelgeuse begins
• 1:00:51
  Speaker 1: to look less like a simple ticking clock and more
• 1:00:55
  Speaker 1: like an enormous living system, changing in several ways at once.
• 1:01:00
  Speaker 1: this may be the most important thing it reveals. Not
• 1:01:03
  Speaker 1: simply when it will explode, but how difficult it is
• 1:01:06
  Speaker 1: to understand a star when you can only see its
• 1:01:09
  Speaker 1: distant light. For a long time, the approximately 2,170 day
• 1:01:15
  Speaker 1: cycle seemed particularly interesting. It was slow, it was regular
• 1:01:20
  Speaker 1: enough to notice, and because Betelgeuse is nearing the end
• 1:01:24
  Speaker 1: of its life, it was tempting to imagine that this
• 1:01:27
  Speaker 1: rhythm might be connected to the star's deepest internal state.
• 1:01:32
  Speaker 1: Perhaps it was the fundamental rhythm. Perhaps it was the
• 1:01:35
  Speaker 1: star's deepest heartbeat. Perhaps, if you could measure it carefully enough,
• 1:01:41
  Speaker 1: you could use that heartbeat to estimate how much longer
• 1:01:44
  Speaker 1: Betelgeuse had before its final collapse. But the possibility of
• 1:01:48
  Speaker 1: Siwaha changes that picture. If the long cycle is caused,
• 1:01:53
  Speaker 1: at least in part, by the gravitational influence of a companion,
• 1:01:58
  Speaker 1: then it should not be treated as a direct countdown
• 1:02:00
  Speaker 1: to the supernova. The source material specifically describes the companion
• 1:02:05
  Speaker 1: interpretation as helping rule out the long cycle as Betelgeuse's
• 1:02:09
  Speaker 1: fundamental mode, meaning that the six-year rhythm may not be
• 1:02:14
  Speaker 1: the rhythm that determines when the star eventually collapses. And
• 1:02:18
  Speaker 1: so the clock becomes quieter. The answer moves farther away.
• 1:02:23
  Speaker 1: Perhaps Betelgeuse will explode within the next few decades. Perhaps
• 1:02:27
  Speaker 1: it will take thousands of years. Perhaps it will take
• 1:02:31
  Speaker 1: tens of thousands of years. The source material allows for
• 1:02:35
  Speaker 1: a timescale of up to roughly 100,000 years, while also
• 1:02:39
  Speaker 1: noting that some estimates have suggested a much nearer possibility.
• 1:02:43
  Speaker 1: You do not need to choose between these possibilities tonight.
• 1:02:47
  Speaker 1: There is no reliable date to memorise. The important thing
• 1:02:51
  Speaker 1: is simply that soon means something very different when you
• 1:02:55
  Speaker 1: are talking about a star. Human time is measured in years.
• 1:03:00
  Speaker 1: A star's final moments are measured in much larger stretches
• 1:03:03
  Speaker 1: of time. And Betelgeuse is still far enough away that
• 1:03:07
  Speaker 1: its light itself takes roughly 650 years to reach you.
• 1:03:12
  Speaker 1: So even the information arriving tonight is already old. You
• 1:03:16
  Speaker 1: are receiving an ancient message from a distant red giant.
• 1:03:20
  Speaker 1: And perhaps that makes the uncertainty feel a little softer.
• 1:03:24
  Speaker 1: The star is not waiting impatiently. It is simply continuing.
• 1:03:28
  Speaker 1: Its outer atmosphere rises and falls. Its brightness changes. Its
• 1:03:33
  Speaker 1: material drifts outward. Its possible companion moves through darkness. And
• 1:03:38
  Speaker 1: somewhere deep inside, nuclear fuel continues to be consumed. Eventually
• 1:03:44
  Speaker 1: gravity will win, but there is no need for that
• 1:03:46
  Speaker 1: ending to happen tonight. For now, Betelgeuse remains a red
• 1:03:50
  Speaker 1: light beside Orion, and while its final fate is uncertain,
• 1:03:55
  Speaker 1: Its strange behaviour is already teaching us something valuable about
• 1:03:59
  Speaker 1: stellar physics. Consider the Great Dimming. At first, the fading
• 1:04:03
  Speaker 1: looked dramatic. The star became around two-thirds dimmer than normal.
• 1:04:09
  Speaker 1: It was tempting to imagine the star itself weakening. But
• 1:04:12
  Speaker 1: observations from the Hubble Space Telescope suggested something gentler. Material
• 1:04:18
  Speaker 1: had escaped from the star. That material cooled. Dust formed.
• 1:04:23
  Speaker 1: and the dust crossed our view, temporarily hiding some of
• 1:04:27
  Speaker 1: the light. By April 2020, Betelgeuse had returned toward its
• 1:04:32
  Speaker 1: normal brightness. The star had not simply switched off. A
• 1:04:36
  Speaker 1: veil had passed between you and the light. Then there
• 1:04:40
  Speaker 1: is Siwaha, a possible companion, faint enough to be almost
• 1:04:44
  Speaker 1: lost beside the enormous red glow. Two independent research groups
• 1:04:49
  Speaker 1: found evidence that the long brightness cycle could be associated
• 1:04:52
  Speaker 1: with a neighbouring star. Later observations with Gemini North produced
• 1:04:57
  Speaker 1: a possible faint image of that companion, although the evidence
• 1:05:01
  Speaker 1: is not yet considered a complete confirmation. Another opportunity is
• 1:05:05
  Speaker 1: expected around 2027, when the companion should again reach a
• 1:05:10
  Speaker 1: favourable separation from Betelgeuse. so even the faintest object in
• 1:05:15
  Speaker 1: this story may eventually help explain the brightest one's strange behaviour.
• 1:05:20
  Speaker 1: And then there is rotation. The light from Betelgeuse appears
• 1:05:24
  Speaker 1: to contain a pattern, suggesting that one side is moving
• 1:05:27
  Speaker 1: toward you while the other moves away. The simplest explanation
• 1:05:32
  Speaker 1: is rotation, but the surface of Betelgeuse is not simple.
• 1:05:36
  Speaker 1: It is filled with enormous convective bubbles. A single bubble
• 1:05:40
  Speaker 1: can span roughly 100 million kilometres. Gas can move outward
• 1:05:45
  Speaker 1: at speeds of up to around 30 kilometres per second,
• 1:05:49
  Speaker 1: and when those enormous regions rise and fall, they can
• 1:05:52
  Speaker 1: create a patchwork of slightly bluer and slightly redder light.
• 1:05:57
  Speaker 1: When viewed from far away, that patchwork can blur into
• 1:06:01
  Speaker 1: something resembling rotation. Simulations suggest that these turbulent patterns could
• 1:06:06
  Speaker 1: be mistaken for rotational motion around 90% of the time,
• 1:06:11
  Speaker 1: under limited observational resolution. So perhaps Betelgeuse really is spinning quickly.
• 1:06:18
  Speaker 1: Perhaps it gained that spin from an earlier companion. Or
• 1:06:22
  Speaker 1: perhaps the star is moving in a completely different way,
• 1:06:26
  Speaker 1: and its turbulent surface has simply fooled our distant measurements.
• 1:06:30
  Speaker 1: The answer may come from better observations. Higher resolution images
• 1:06:35
  Speaker 1: could allow astronomers to separate the giant bubbles from the
• 1:06:38
  Speaker 1: broader motion of the star. And eventually, The blurred red
• 1:06:42
  Speaker 1: point in Orion may become a little clearer. Not completely clear.
• 1:06:46
  Speaker 1: The distance is still enormous. But clearer. Enough to distinguish
• 1:06:51
  Speaker 1: one possibility from another. And perhaps this is what Betelgeuse
• 1:06:55
  Speaker 1: has really been telling us all along. A star does
• 1:06:58
  Speaker 1: not need to be simple just because it appears as
• 1:07:00
  Speaker 1: a single point of light. Behind that tiny red point
• 1:07:04
  Speaker 1: is a vast atmosphere. There are rhythms. There are clouds.
• 1:07:08
  Speaker 1: There are bubbles. There may be a companion, there may
• 1:07:11
  Speaker 1: be rotation, there may be motion that only looks like rotation.
• 1:07:16
  Speaker 1: There is a future supernova somewhere ahead, and there is
• 1:07:20
  Speaker 1: a great deal of uncertainty between the present moment and
• 1:07:23
  Speaker 1: that distant ending. You can imagine Betelgeuse now, quietly suspended
• 1:07:28
  Speaker 1: beside Orion. No explosion, no sudden flash, just red light.
• 1:07:34
  Speaker 1: The possible companion moving silently somewhere nearby. The atmosphere rising
• 1:07:39
  Speaker 1: and falling. The star slowly changing as it has changed
• 1:07:43
  Speaker 1: for millions of years. And all of it happening far
• 1:07:46
  Speaker 1: beyond your reach. Far beyond your ordinary sense of time.
• 1:07:51
  Speaker 1: You can simply let the image become smaller now. The
• 1:07:54
  Speaker 1: enormous star becomes a point. The point becomes a faint
• 1:07:58
  Speaker 1: red glow. And the glow becomes one more quiet light
• 1:08:02
  Speaker 1: among thousands. The universe does not need to explain itself
• 1:08:06
  Speaker 1: all at once. Sometimes understanding arrives slowly, a little piece
• 1:08:11
  Speaker 1: of evidence here, another observation there, a faint companion appearing
• 1:08:16
  Speaker 1: from the darkness, a cloud of dust crossing a distant face,
• 1:08:20
  Speaker 1: a subtle movement hidden inside light, and eventually perhaps the
• 1:08:25
  Speaker 1: pieces will settle into a clearer picture. But for tonight
• 1:08:29
  Speaker 1: they can remain gently unfinished. Beetlejuice is still there, still glowing,
• 1:08:35
  Speaker 1: still moving. still keeping some of its secrets. And somewhere
• 1:08:40
  Speaker 1: in that enormous red atmosphere, long before its final light
• 1:08:44
  Speaker 1: reaches us, the next small change is already beginning. And
• 1:08:50
  Speaker 1: now you can let Betelgeuse become distant again. You have
• 1:08:54
  Speaker 1: spent this quiet journey beside an enormous red star, looking
• 1:08:59
  Speaker 1: gently into its changes, light, following rhythms that take years
• 1:09:03
  Speaker 1: to unfold, watching clouds of dust drift across its surface,
• 1:09:08
  Speaker 1: imagining enormous bubbles of hot gas rising through its atmosphere,
• 1:09:12
  Speaker 1: and wondering whether another small star may be moving quietly
• 1:09:16
  Speaker 1: around it. There is nothing more you need to solve.
• 1:09:19
  Speaker 1: You do not need to know exactly when Betelgeuse will explode.
• 1:09:23
  Speaker 1: No one knows. Perhaps the final collapse is relatively close
• 1:09:27
  Speaker 1: on the scale of cosmic time. Perhaps it is still
• 1:09:30
  Speaker 1: tens of thousands of years away. Perhaps the star will
• 1:09:33
  Speaker 1: continue shining long after every person listening tonight has become
• 1:09:38
  Speaker 1: part of the distant history of Earth. And that uncertainty
• 1:09:42
  Speaker 1: can simply remain where it is. Far away. Quiet. Unhurried.
• 1:09:48
  Speaker 1: because Betelgeuse does not need you to know its future
• 1:09:51
  Speaker 1: in order to continue existing. Tonight its ancient red light
• 1:09:56
  Speaker 1: is enough. You can imagine that light leaving the star,
• 1:09:59
  Speaker 1: crossing the darkness, moving through the space between stars for
• 1:10:03
  Speaker 1: hundreds of years before finally arriving here. When you see Betelgeuse,
• 1:10:09
  Speaker 1: you are seeing an old message, a message that began
• 1:10:12
  Speaker 1: its journey long ago. And perhaps somewhere inside that idea
• 1:10:16
  Speaker 1: There is a gentle kind of stillness. The universe is
• 1:10:20
  Speaker 1: full of things that take time. Light takes time. Stars
• 1:10:24
  Speaker 1: take time. Dust takes time to travel. Companions take time
• 1:10:29
  Speaker 1: to orbit. A red supergiant takes an immense amount of
• 1:10:33
  Speaker 1: time to live, change, and eventually reach its final moment.
• 1:10:38
  Speaker 1: Nothing has to happen quickly. Nothing needs to happen tonight.
• 1:10:43
  Speaker 1: The Great Dimming came and went. For a while, The
• 1:10:46
  Speaker 1: star became much fainter. Then the dust moved onward. The
• 1:10:51
  Speaker 1: view cleared, and Betelgeuse returned to its familiar place beside Orion.
• 1:10:56
  Speaker 1: Its brightness continues to rise and fall. Its atmosphere continues
• 1:11:01
  Speaker 1: to move. Its long rhythms continue to overlap. And perhaps
• 1:11:05
  Speaker 1: somewhere nearby, Siwaha continues its quiet orbit, if that faint
• 1:11:10
  Speaker 1: companion really is there, around and around. So slowly, that
• 1:11:16
  Speaker 1: an entire human life could pass while the stars barely
• 1:11:20
  Speaker 1: seemed to change. You can imagine the two of them now,
• 1:11:24
  Speaker 1: the enormous red giant and the much smaller companion, neither
• 1:11:28
  Speaker 1: one making a sound, neither one aware of the questions
• 1:11:32
  Speaker 1: we ask from so far away. They simply move according
• 1:11:36
  Speaker 1: to gravity, quietly, naturally, and perhaps the strange six-year rhythm
• 1:11:42
  Speaker 1: in Betelgeuse's light is partly connected to that distant relationship.
• 1:11:48
  Speaker 1: Perhaps not. The universe allows both possibilities to remain open.
• 1:11:53
  Speaker 1: And then there is the question of rotation. Maybe Betelgeuse
• 1:11:56
  Speaker 1: truly spins faster than we expect. Maybe, long ago, another
• 1:12:01
  Speaker 1: star gave it some of its motion. Or perhaps the
• 1:12:05
  Speaker 1: apparent rotation is created by enormous convective bubbles moving across
• 1:12:09
  Speaker 1: its surface. Great regions of hot gas rising, cooler regions sinking,
• 1:12:15
  Speaker 1: light shifting slightly as those regions move toward us and
• 1:12:18
  Speaker 1: away from us, a whole world of movement hidden inside
• 1:12:22
  Speaker 1: a single point of red light. From Earth, you cannot
• 1:12:25
  Speaker 1: see each bubble, you cannot watch each current, you cannot
• 1:12:29
  Speaker 1: separate every movement, you receive only the combined light. And yet,
• 1:12:34
  Speaker 1: from that tiny signal, astronomers slowly reconstruct a picture of
• 1:12:38
  Speaker 1: what may be happening hundreds of light-years away. That is
• 1:12:42
  Speaker 1: one of the quiet wonders of science. Not that every
• 1:12:45
  Speaker 1: mystery is solved immediately, but that even a faint change
• 1:12:48
  Speaker 1: in distant light can become a clue, a small shift,
• 1:12:52
  Speaker 1: a slight dimming, a recurring rhythm, a tiny movement, a
• 1:12:57
  Speaker 1: faint companion. Each one adds another piece, and sometimes the
• 1:13:02
  Speaker 1: pieces do not fit perfectly. That is all right. Understanding
• 1:13:06
  Speaker 1: can remain incomplete. A mystery does not become less beautiful
• 1:13:10
  Speaker 1: because you have not finished explaining it. Perhaps Betelgeuse is
• 1:13:14
  Speaker 1: teaching you this without words. It is an enormous star,
• 1:13:19
  Speaker 1: but from Earth it appears as a tiny point. It
• 1:13:22
  Speaker 1: is constantly moving, but from one night to the next
• 1:13:26
  Speaker 1: it seems almost still. It is changing throughout its atmosphere,
• 1:13:30
  Speaker 1: yet its red glow can remain familiar for generations. It
• 1:13:34
  Speaker 1: may already be approaching its final transformation. Yet that ending
• 1:13:38
  Speaker 1: could still be unimaginably far away. And if one day
• 1:13:42
  Speaker 1: its light finally changes forever, the change will travel outward
• 1:13:47
  Speaker 1: through space. Eventually that light will reach Earth. If humanity
• 1:13:51
  Speaker 1: is here to see it, the night sky may hold
• 1:13:54
  Speaker 1: an extraordinary new brightness. But there is no danger waiting
• 1:13:58
  Speaker 1: for you tonight. Betelgeuse is far beyond the region where
• 1:14:02
  Speaker 1: a supernova would be expected to cause severe harm to Earth.
• 1:14:07
  Speaker 1: You can let that thought settle gently. The red giant
• 1:14:10
  Speaker 1: is distant. The darkness between you and it is vast.
• 1:14:14
  Speaker 1: And for now, the universe keeps its distance beautifully. So
• 1:14:19
  Speaker 1: perhaps you can allow your attention to return to the
• 1:14:22
  Speaker 1: room around you. The distant star can become smaller. The
• 1:14:26
  Speaker 1: red glow can soften. Orion can fade into the wider sky.
• 1:14:32
  Speaker 1: The sky can become simply darkness again. And the darkness
• 1:14:35
  Speaker 1: can become quiet. You can feel the weight of your
• 1:14:38
  Speaker 1: body resting wherever you are. You can notice the slow
• 1:14:42
  Speaker 1: movement of your breathing. There is nothing to calculate, nothing
• 1:14:46
  Speaker 1: to predict, nothing to understand perfectly. You can simply rest.
• 1:14:52
  Speaker 1: Far above, stars continue their long lives. Some are being born,
• 1:14:56
  Speaker 1: some are changing, some have already disappeared, while their ancient
• 1:15:00
  Speaker 1: light continues travelling toward distant worlds. And somewhere among them,
• 1:15:06
  Speaker 1: Betelgeuse continues to glow, still red, still enormous, still changing,
• 1:15:12
  Speaker 1: still keeping some of its secrets. Perhaps one day we
• 1:15:16
  Speaker 1: will understand its strange rhythms more clearly. Perhaps we will
• 1:15:20
  Speaker 1: know whether Siwaha truly circles the giant. Perhaps better observations
• 1:15:26
  Speaker 1: will finally tell us whether Betelgeuse is spinning rapidly, or
• 1:15:30
  Speaker 1: whether its enormous convection has been gently fooling our distant eyes.
• 1:15:35
  Speaker 1: And perhaps— One quiet night far in the future, the
• 1:15:39
  Speaker 1: final message from the star will begin its journey toward Earth.
• 1:15:43
  Speaker 1: But tonight, there is only the older light, the light
• 1:15:46
  Speaker 1: already travelling, the light that has crossed hundreds of years
• 1:15:50
  Speaker 1: of darkness simply to arrive here. You do not need
• 1:15:54
  Speaker 1: to follow it any farther. You can let it drift
• 1:15:57
  Speaker 1: away now, past the room, past the clouds, past the
• 1:16:02
  Speaker 1: blue atmosphere of Earth, into the darkness beyond. And as
• 1:16:06
  Speaker 1: you rest, the stars can remain where they have always been,
• 1:16:10
  Speaker 1: moving slowly through immense distances, carrying their light across time,
• 1:16:16
  Speaker 1: while you remain here, safe and quiet, with nothing to
• 1:16:19
  Speaker 1: do but listen and drift. The universe will continue without hurry.
• 1:16:24
  Speaker 1: Betelgeuse will continue its slow breathing. The possible companion will
• 1:16:28
  Speaker 1: continue its distant path. The galaxies will continue moving. The
• 1:16:33
  Speaker 1: light will continue travelling. and somewhere, very far away, the
• 1:16:38
  Speaker 1: red giant will continue glowing softly in Orion. You can
• 1:16:43
  Speaker 1: let the image become faint now. A red point, then
• 1:16:46
  Speaker 1: a smaller point, then only a trace of light, and finally, perhaps,
• 1:16:51
  Speaker 1: nothing that you need to see at all, just darkness,
• 1:16:55
  Speaker 1: just breathing, just rest. And somewhere beyond the darkness, the
• 1:16:59
  Speaker 1: story of Betelgeuse continues, slowly, quietly, without needing to reach
• 1:17:05
  Speaker 1: an ending tonight.