Latest / Boring Science / Pluto Is Stranger Than You Think _ What NASA Found Beyond Neptune

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Pluto Is Stranger Than You Think _ What NASA Found Beyond Neptune · 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 what NASA found on Pluto,
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  Speaker 1: not to learn everything about this distant little world, but
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  Speaker 1: simply to notice it, slowly, calmly, one quiet detail at
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  Speaker 1: a time. Before you settle in, if you truly enjoy
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  Speaker 1: these calm journeys through interesting facts about science, You're welcome
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  Speaker 1: to like this video and subscribe, only if it feels
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  Speaker 1: right for you. And when you're ready, let me know
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  Speaker 1: in the comments where you're listening from and what time
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  Speaker 1: it is right now. It's always a quiet joy to
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  Speaker 1: see how many places and moments gather here together. Now,
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  Speaker 1: dim the lights, perhaps let a fan hum softly in
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  Speaker 1: the background and allow your breathing to become a little slower.
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  Speaker 1: There is nothing you need to remember tonight. There is
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  Speaker 1: nothing you need to do You are safe, you can
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  Speaker 1: simply listen and drift. And somewhere far beyond the familiar planets,
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  Speaker 1: where sunlight has become faint and the darkness is wide,
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  Speaker 1: a small frozen world is moving quietly around the sun.
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  Speaker 1: Its name is Pluto. And for a long time, we
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  Speaker 1: thought we knew what Pluto was. Perhaps we were wrong.
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  Speaker 1: Perhaps we simply had not looked closely enough. You may
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  Speaker 1: remember Pluto as the ninth planet. For many years, that
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  Speaker 1: was the simple picture, the one quietly placed at the
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  Speaker 1: outer edge of the solar system, after Neptune, small and distant,
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  Speaker 1: circling the sun in the cold. And perhaps when you
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  Speaker 1: imagined the solar system as a child, you imagined a
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  Speaker 1: neat little family, with the planets following one another in order,
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  Speaker 1: each with its own place, each belonging to a familiar category.
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  Speaker 1: But the solar system has never been quite that tidy.
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  Speaker 1: The way we name worlds has changed many times, as
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  Speaker 1: our ability to see them has changed. In the 19th century,
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  Speaker 1: astronomers could identify objects in the sky that seemed to
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  Speaker 1: deserve names and categories of their own. As more objects
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  Speaker 1: were discovered, the old definitions became less comfortable. What counted
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  Speaker 1: as a planet slowly became a question that needed a
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  Speaker 1: more careful answer. Then, in 1930… a young and largely
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  Speaker 1: self-taught astronomer named Clyde Tombaugh began searching for something that
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  Speaker 1: astronomers had called Planet X, a hypothetical distant world that
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  Speaker 1: might explain strange movements observed in the outer solar system.
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  Speaker 1: Night after night he compared photographs of the stars. Ten
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  Speaker 1: months passed, most of the points of light remained exactly
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  Speaker 1: where they seemed to belong, and then, among those countless
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  Speaker 1: distant stars, one tiny point appeared to have moved. It
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  Speaker 1: was faint. It was slow. It was far beyond Neptune.
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  Speaker 1: Tombaugh had been looking for a new planet, and at
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  Speaker 1: the time, this small moving world appeared to fit the description.
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  Speaker 1: So Pluto entered our imagination as the ninth planet. For decades,
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  Speaker 1: Pluto remained there, at the quiet edge of the planetary family.
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  Speaker 1: But while we were looking at Pluto from very far away,
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  Speaker 1: we did not yet know something important. Pluto was not alone.
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  Speaker 1: Beyond Neptune is a vast region filled with small, cold objects,
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  Speaker 1: remnants of the early solar system moving through deep darkness. Today,
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  Speaker 1: we call this region the Kuiper Belt, and Pluto is
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  Speaker 1: one member of it. It is not even the largest
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  Speaker 1: object in this distant population. One reason Pluto was noticed
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  Speaker 1: so early is that its surface reflects a surprising amount
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  Speaker 1: of sunlight, making the little world appear brighter and more
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  Speaker 1: prominent than many of its neighbours. From Earth, all of
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  Speaker 1: this distance becomes compressed into a tiny point of light.
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  Speaker 1: You look upward, and Pluto is nowhere to be seen
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  Speaker 1: with your unaided eyes. Yet, somewhere beyond the familiar planets,
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  Speaker 1: it is there, moving, turning, waiting. And then, in 2006…
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  Speaker 1: Our definition of a planet changed. A planet, according to
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  Speaker 1: the new definition, needed not only to orbit the Sun,
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  Speaker 1: but also to have enough gravitational influence to dominate the
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  Speaker 1: region around its path. You can imagine this gently, not
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  Speaker 1: as a cosmic battle, but as a large object gradually
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  Speaker 1: becoming the main presence in its neighbourhood, while smaller objects
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  Speaker 1: remain gathered around it. Pluto did not meet that final condition.
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  Speaker 1: It remained a world but it became classified as a
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  Speaker 1: dwarf planet. Nothing physical happened to Pluto that day. Its
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  Speaker 1: mountains did not disappear, its frozen plains did not change.
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  Speaker 1: Its long journey around the Sun continued exactly as before,
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  Speaker 1: only our description of it changed. And perhaps that is
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  Speaker 1: one of the quiet lessons hidden inside Pluto. Sometimes a
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  Speaker 1: name changes because we have discovered that the world is
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  Speaker 1: more complicated than the name allowed. Pluto itself has always
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  Speaker 1: been moving along its unusual path. Its orbit around the
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  Speaker 1: Sun is stretched rather than nearly circular, and it is
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  Speaker 1: tilted by about 17 degrees compared with the broad plane
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  Speaker 1: followed by most of the planets. So Pluto does not
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  Speaker 1: simply travel around the Sun along the same flat road.
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  Speaker 1: Its path rises above and falls below that familiar plane,
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  Speaker 1: carrying it through a much larger, stranger loop. and it
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  Speaker 1: takes Pluto about 248 Earth years to complete that journey.
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  Speaker 1: Imagine that for a moment. A human lifetime is only
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  Speaker 1: a small portion of one Pluto year. A child born
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  Speaker 1: on Pluto would grow old without seeing a complete revolution
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  Speaker 1: around the Sun. And during parts of its long journey,
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  Speaker 1: Pluto can travel closer to the Sun than Neptune. Even
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  Speaker 1: its path refuses to fit neatly into the picture we
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  Speaker 1: once had. Yet from such a great distance, all of
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  Speaker 1: this complexity remained hidden. Pluto looked small. It looked quiet.
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  Speaker 1: It looked frozen. It looked almost alone. Then humanity began
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  Speaker 1: building a machine that could travel there. A small spacecraft
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  Speaker 1: called New Horizons was launched in 2006, the very year
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  Speaker 1: Pluto's classification changed. Its purpose was wonderfully simple. Go farther
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  Speaker 1: than we had ever gone before. Reach Pluto, and finally
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  Speaker 1: see what this distant world was actually like. The journey
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  Speaker 1: would take years. But for Pluto, years are almost nothing.
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  Speaker 1: It had already been travelling around the sun for billions
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  Speaker 1: of years, quietly following its tilted path through the cold.
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  Speaker 1: And now, for the first time, something made by you
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  Speaker 1: was coming toward it. Something carrying cameras. Something carrying instruments.
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  Speaker 1: something carrying the questions of an entire planet. Far ahead,
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  Speaker 1: Pluto was still only a tiny point of light, and
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  Speaker 1: as new horizons moved deeper into the darkness, that point
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  Speaker 1: would slowly begin to grow. Not quickly, not dramatically, just
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  Speaker 1: a little more with every passing day, until the distant
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  Speaker 1: point became a world, and when that happened, Pluto would
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  Speaker 1: no longer be simply the little object we once called
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  Speaker 1: the ninth planet. It would become something much stranger, much
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  Speaker 1: more beautiful, and much more alive than anyone could see
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  Speaker 1: from Earth. You can imagine Earth becoming smaller behind you,
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  Speaker 1: not all at once, not dramatically, just slowly, quietly, until
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  Speaker 1: the familiar blue world begins to feel like something far away.
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  Speaker 1: In 2006, while Pluto was being given a new place
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  Speaker 1: in our understanding of the solar system, a small spacecraft
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  Speaker 1: was beginning a journey toward it. Its name was New Horizons.
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  Speaker 1: The distance to Pluto was the greatest obstacle. There was
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  Speaker 1: no road to follow, no station waiting halfway there, no
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  Speaker 1: place to stop and rest. Only darkness, gravity, and a
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  Speaker 1: destination moving through the outer solar system. so New Horizons
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  Speaker 1: left Earth with an enormous burst of speed. The spacecraft
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  Speaker 1: itself was relatively small, weighing about 1,000 pounds, but it
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  Speaker 1: was placed on a powerful Atlas V rocket, carrying it
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  Speaker 1: away from Earth with enough energy to begin one of
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  Speaker 1: the fastest departures ever made by a spacecraft toward the
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  Speaker 1: outer solar system. And then something remarkable happened. Only about
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  Speaker 1: nine hours after leaving Earth, New Horizons was already passing
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  Speaker 1: the distance of the moon. You can let that distance
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  Speaker 1: settle quietly in your mind. The moon, which usually seems
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  Speaker 1: so far away when you look at it from your window,
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  Speaker 1: was already behind the spacecraft. Earth was behind it too.
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  Speaker 1: And ahead there was only the long darkness. The spacecraft
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  Speaker 1: continued outward, carrying cameras, instruments, and a quiet collection of questions.
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  Speaker 1: What would Pluto look like? Would it be smooth? Would
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  Speaker 1: it be covered in ancient craters? Would it simply be
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  Speaker 1: a frozen, inactive remnant from the early solar system? At
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  Speaker 1: this point, no one could really know, so New Horizons
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  Speaker 1: kept moving. And after about a year, another world appeared ahead. Jupiter,
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  Speaker 1: the largest planet in our solar system. For a little while,
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  Speaker 1: New Horizons turned its attention to this enormous planet and
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  Speaker 1: its many moons. Its cameras were tested. Images were taken.
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  Speaker 1: Among them was a remarkable view of volcanic activity on Io,
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  Speaker 1: one of Jupiter's moons. For a spacecraft travelling toward Pluto,
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  Speaker 1: this was an unexpected moment of discovery. a quiet reminder
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  Speaker 1: that even while travelling toward one distant world, other worlds
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  Speaker 1: could briefly appear along the way. But Jupiter had another purpose.
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  Speaker 1: Its immense gravity could help New Horizons travel farther. You
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  Speaker 1: can imagine the spacecraft approaching the giant planet, not stopping,
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  Speaker 1: not landing, not being captured, but passing through the region
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  Speaker 1: where Jupiter's gravity could gently alter its path and increase
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  Speaker 1: its speed. Scientists call this a gravity assist. The phrase
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  Speaker 1: sounds technical, but the idea is quite simple. A spacecraft
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  Speaker 1: can borrow a little of the motion of a planet
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  Speaker 1: as it passes nearby, changing its own speed and direction
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  Speaker 1: without needing to carry enough fuel to provide all of
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  Speaker 1: that movement by itself. Jupiter became a kind of gravitational
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  Speaker 1: stepping stone. New horizons passed by, received its gentle push,
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  Speaker 1: and continued onward. And then the darkness became larger, much larger.
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  Speaker 1: The planets of the inner solar system were falling farther behind.
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  Speaker 1: The sun was becoming smaller in the distance. The warmth
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  Speaker 1: and brightness that define our familiar neighbourhood were gradually becoming
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  Speaker 1: less noticeable. Ahead, Pluto was still waiting. Even after the
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  Speaker 1: help from Jupiter, New Horizons needed about eight more years
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  Speaker 1: to cross the outer solar system before reaching Pluto. Eight years.
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  Speaker 1: For you, eight years can contain childhood memories, new homes,
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  Speaker 1: different jobs, friendships, seasons, ordinary mornings, quiet evenings, and countless
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  Speaker 1: small changes. For Pluto, eight years are barely a breath.
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  Speaker 1: It continued along its enormous orbit. The spacecraft continued along
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  Speaker 1: its own path, two travellers moving through the same solar system.
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  Speaker 1: separated by billions of kilometres of darkness. And during those
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  Speaker 1: long years, New Horizons became almost like a tiny moving room.
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  Speaker 1: Inside it, instruments waited, cameras waited, computers waited. The spacecraft
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  Speaker 1: simply continued forward. There was no sound of an engine
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  Speaker 1: roaring through space. There was no wind against its body.
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  Speaker 1: Nothing around it rushed past in the way that air
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  Speaker 1: rushes past a car. It moved through a nearly empty environment,
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  Speaker 1: surrounded by darkness and distant points of light. And slowly,
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  Speaker 1: very slowly, Pluto began to come closer. At first it
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  Speaker 1: was only another tiny point, then the cameras could begin
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  Speaker 1: to distinguish it more clearly. And eventually, another small point
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  Speaker 1: appeared nearby. Charon, Pluto's largest moon. Two faint lights, separated
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  Speaker 1: from the background stars. At first they were only points.
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  Speaker 1: Then they began to grow. Day by day, image by image,
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  Speaker 1: the distant points became recognisable. There was Pluto, and beside
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  Speaker 1: Pluto was Charon. The first close encounter with these worlds
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  Speaker 1: was finally approaching. For nearly a decade, New Horizons had
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  Speaker 1: been travelling through the darkness toward this moment, and yet
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  Speaker 1: the spacecraft still had only a short time to see them.
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  Speaker 1: It would not enter orbit around Pluto and remain there
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  Speaker 1: for years. It would pass through the system, gather as
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  Speaker 1: much information as possible, and continue onward. So there was
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  Speaker 1: no time to waste, even though the journey itself had
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  Speaker 1: been so slow. Everything the spacecraft had carried across that
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  Speaker 1: enormous distance was about to become important. The cameras would
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  Speaker 1: begin looking more closely. The instruments would begin measuring the
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  Speaker 1: faint atmosphere. The surfaces would begin to reveal their colours
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  Speaker 1: and shapes, and the two tiny points of light would
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  Speaker 1: finally become worlds. You can imagine new horizons approaching now,
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  Speaker 1: still moving silently, with Pluto growing larger ahead, the sun
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  Speaker 1: far behind, the stars surrounding you. And somewhere in that
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  Speaker 1: deep darkness, a small frozen world is waiting to show
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  Speaker 1: you something no human eye has ever seen from such
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  Speaker 1: a close distance. Not a simple ball of ice, not
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  Speaker 1: merely a former planet, but a landscape, a sky, moving ice, mountains, haze,
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  Speaker 1: and perhaps, hidden beneath all that frozen quiet, something even warmer.
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  Speaker 1: As New Horizons continued toward Pluto, the distant point of
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  Speaker 1: light slowly became easier to recognise, and then, beside it,
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  Speaker 1: another point appeared. It was smaller, fainter, but it was there, Charon,
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  Speaker 1: Pluto's largest moon. From a great distance, the two worlds
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  Speaker 1: might have looked like nothing more than a pair of
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  Speaker 1: tiny lights resting together in the darkness. But the closer
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  Speaker 1: New Horizons came, the stranger their relationship became. Charon is
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  Speaker 1: roughly half the size of Pluto, which is unusually large
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  Speaker 1: for a moon, compared with the world it accompanies. And
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  Speaker 1: Charon stays remarkably close. The distance between the two worlds
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  Speaker 1: is less than 20,000 kilometres, while our own moon is
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  Speaker 1: almost 400,000 kilometres from Earth. You can let that difference
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  Speaker 1: settle quietly in your imagination. When you look at the
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  Speaker 1: moon from Earth, it feels like a distant companion, hanging
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  Speaker 1: far away in the night sky. But if you could
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  Speaker 1: somehow stand on Pluto, Charon would feel much closer. It
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  Speaker 1: would be a constant presence in the darkness, and there
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  Speaker 1: would be something unusual about the way it appeared. Charon
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  Speaker 1: does not slowly wander across Pluto's sky in the way
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  Speaker 1: our moon moves across Earth's. Instead, Pluto and Charon have
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  Speaker 1: become locked together. Each world keeps the same side facing
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  Speaker 1: the other. Scientists call this mutual tidal locking, but you
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  Speaker 1: do not need to hold on to the technical phrase.
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  Speaker 1: You can simply imagine two worlds turning together, each showing
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  Speaker 1: the other the same face, again and again, for an
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  Speaker 1: extraordinarily long time. If you were standing on the side
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  Speaker 1: of Pluto that faces Charon, you would always see the
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  Speaker 1: same moon in the same part of the sky. It
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  Speaker 1: would not rise in the east. It would not slowly
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  Speaker 1: cross overhead. It would simply remain there, suspended in the darkness.
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  Speaker 1: And if you walked around to the far side of Pluto,
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  Speaker 1: Charon would disappear completely. Not because the moon had moved away,
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  Speaker 1: not because the moon had set, but because Pluto itself
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  Speaker 1: would now be between you and Charon. There is something
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  Speaker 1: wonderfully quiet about that arrangement. Two worlds close together, two
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  Speaker 1: worlds turning slowly, two worlds each keeping the same face
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  Speaker 1: toward the other. And yet their strange relationship becomes even
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  Speaker 1: more interesting when you look at the way they move
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  Speaker 1: through space. You might naturally imagine Charon circling Pluto, the
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  Speaker 1: way our moon circles Earth. But Pluto and Charon are
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  Speaker 1: more evenly matched. Charon is large enough, compared with Pluto,
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  Speaker 1: that their combined centre of mass lies between the two
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  Speaker 1: worlds rather than deep inside Pluto. The centre of mass
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  Speaker 1: is simply the point around which the two bodies balance
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  Speaker 1: as they move together. You can picture it as an
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  Speaker 1: invisible point floating in the darkness between them. Pluto moves
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  Speaker 1: around that point. Charon moves around that point too. So,
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  Speaker 1: rather than imagining a large planet sitting still while a
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  Speaker 1: smaller moon circles around it, you can imagine two worlds
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  Speaker 1: quietly moving around an empty place between them. There is
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  Speaker 1: no little object there, no hidden star, no tiny dark planet,
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  Speaker 1: nothing that you could see, just the balance created by gravity.
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  Speaker 1: The source describes how the unusual movement can appear almost
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  Speaker 1: as though the two worlds are circling a point in
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  Speaker 1: empty space. And perhaps that is a gentler way to
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  Speaker 1: picture gravity. Not always as something pulling dramatically. Sometimes gravity
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  Speaker 1: simply arranges things. It gives two worlds a shared rhythm.
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  Speaker 1: It keeps them together. It allows them to move through
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  Speaker 1: darkness without drifting completely apart. For a moment... Imagine yourself
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  Speaker 1: floating between Pluto and Charon. There is no ground beneath you,
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  Speaker 1: no air moving past your face, no sound, only the
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  Speaker 1: pale surfaces of two distant worlds, suspended against a black sky.
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  Speaker 1: Pluto on one side, Charon on the other, and between them,
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  Speaker 1: that quiet, invisible point around which their combined motion is balanced.
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  Speaker 1: You might notice that neither world seems to be rushing.
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  Speaker 1: Of course they are moving, they are travelling through the
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  Speaker 1: solar system, following their enormous path around the sun. But
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  Speaker 1: from your imagined position between them, the motion feels almost imperceptible.
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  Speaker 1: A slow turning, a patient relationship, a dance too slow
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  Speaker 1: for human eyes to notice in a single moment. And
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  Speaker 1: that slowness is important, because Pluto and Charon have been
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  Speaker 1: together for an immense stretch of time. The source suggests
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  Speaker 1: that their unusual relationship may have begun through an ancient collision,
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  Speaker 1: when the young worlds encountered one another early in the
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  Speaker 1: history of the solar system, That idea will become important later,
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  Speaker 1: but for now, you can simply let it remain as
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  Speaker 1: a quiet possibility. Perhaps, long ago, two young worlds met
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  Speaker 1: in the darkness. Perhaps the encounter changed both of them.
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  Speaker 1: And perhaps, instead of separating completely, they remained together. Now,
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  Speaker 1: billions of years later, they continue their slow gravitational relationship.
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  Speaker 1: Two worlds, one shared rhythm. one invisible point between them.
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  Speaker 1: And while New Horizons was observing this strange arrangement, something
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  Speaker 1: else was beginning to appear in its cameras. The spacecraft
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  Speaker 1: was getting close enough to see Pluto itself. Not merely
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  Speaker 1: as a bright point, not as a small dot beside Charon,
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  Speaker 1: but as a landscape. At first the details were faint.
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  Speaker 1: Then shapes began to emerge, light and shadow, bright regions,
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  Speaker 1: dark regions, hints of colour, and slowly the simple image
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  Speaker 1: of a frozen ball began to disappear. Pluto was becoming
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  Speaker 1: a place, a place with mountains and plains, a place
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  Speaker 1: with ice that could move, a place with a thin
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  Speaker 1: atmosphere above its surface, a place whose colours were far
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  Speaker 1: more complicated than anyone might have expected, and somewhere within
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  Speaker 1: those first images was a shape that would soon become
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  Speaker 1: one of the most recognisable features in the distant solar system,
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  Speaker 1: a great pale heart, quietly appearing across Pluto's surface. As
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  Speaker 1: New Horizons came closer, Pluto began to lose its appearance
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  Speaker 1: as a distant point of light. The small world was
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  Speaker 1: becoming a landscape, and the first thing you might notice
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  Speaker 1: is that Pluto is not simply white, it is not
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  Speaker 1: a perfectly smooth blue sphere. and it is not the
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  Speaker 1: featureless frozen ball that people once imagined when they thought
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  Speaker 1: about a world so far from the sun. Instead, its
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  Speaker 1: surface carries many different shades. There are pale regions, bright
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  Speaker 1: white areas, soft blues, darker patches, yellowish tones, and broad
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  Speaker 1: regions of reddish and burnt orange colour. The colours are subtle,
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  Speaker 1: softened by the enormous distance from the sun, but they
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  Speaker 1: are there. And as the images from New Horizons became clearer,
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  Speaker 1: one feature seemed almost impossible to miss. A great pale
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  Speaker 1: shape stretched across part of Pluto. A heart. It was enormous.
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  Speaker 1: Not a small mark on the surface, but a broad
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  Speaker 1: region covering a substantial portion of the visible side. Within
• 22:54
  Speaker 1: this heart-shaped area lies a vast frozen plane called Sputnik Planitia.
• 22:59
  Speaker 1: You do not need to remember the name. you can
• 23:01
  Speaker 1: simply imagine a wide, pale landscape extending beneath a distant,
• 23:06
  Speaker 1: weak sun, a frozen plain so large that it is
• 23:09
  Speaker 1: difficult to imagine its full size from the ground. The
• 23:13
  Speaker 1: source describes the plain as roughly comparable in area to
• 23:16
  Speaker 1: the state of Texas. But the most interesting thing about
• 23:19
  Speaker 1: Sputnik Planitia may not be its size. It is how
• 23:24
  Speaker 1: young it appears. When a surface sits exposed in space
• 23:28
  Speaker 1: for billions of years, you would expect it to collect scars.
• 23:33
  Speaker 1: Small impacts. Large impacts. Dark marks where pieces of rock
• 23:38
  Speaker 1: and ice have struck the ground. The surface of many
• 23:42
  Speaker 1: old planetary bodies becomes something like a quiet record of time,
• 23:46
  Speaker 1: with each crater preserving a small memory of an ancient collision.
• 23:51
  Speaker 1: But parts of Pluto do not seem to carry many
• 23:53
  Speaker 1: of those scars. The Great Plane is remarkably smooth. And
• 23:58
  Speaker 1: that tells you something. The surface may not have been
• 24:01
  Speaker 1: sitting quietly for all of Pluto's history. Something has been
• 24:05
  Speaker 1: changing it, something has been smoothing it, something has been
• 24:10
  Speaker 1: renewing it. You can imagine the surface as a frozen
• 24:13
  Speaker 1: landscape that slowly forgets its oldest marks. A crater appears,
• 24:19
  Speaker 1: time passes, ice moves, the crater becomes softer, and eventually
• 24:25
  Speaker 1: the surface looks young again. Scientists describe this as geological activity,
• 24:31
  Speaker 1: but you can think of it more simply as Pluto
• 24:34
  Speaker 1: slowly changing beneath the darkness. And then comes one of
• 24:38
  Speaker 1: the strangest discoveries. The ice on Pluto can move. At first,
• 24:43
  Speaker 1: this sounds almost impossible. Pluto is extraordinarily cold, so cold
• 24:49
  Speaker 1: that the kind of water ice you might imagine on
• 24:51
  Speaker 1: Earth becomes extremely rigid there, more like hard stone than
• 24:56
  Speaker 1: something that could slowly flow. But Pluto has other kinds
• 24:59
  Speaker 1: of ice. One of the most important is frozen nitrogen.
• 25:04
  Speaker 1: Nitrogen is a gas here on Earth, surrounding you every moment,
• 25:08
  Speaker 1: quietly filling much of the air you breathe. On Pluto,
• 25:13
  Speaker 1: in the extreme cold of the distant solar system, nitrogen
• 25:16
  Speaker 1: can freeze into a solid, and under the right conditions,
• 25:20
  Speaker 1: that frozen nitrogen can slowly move. Not quickly, not like
• 25:26
  Speaker 1: water flowing through a river. not like snow sliding down
• 25:29
  Speaker 1: a mountain. It moves with the patient slowness of a
• 25:33
  Speaker 1: landscape changing over immense stretches of time. Imagine standing at
• 25:39
  Speaker 1: the edge of Sputnik Planitia. The plain looks completely still.
• 25:44
  Speaker 1: There is no sound, no wind brushing against your clothing,
• 25:48
  Speaker 1: no warmth beneath your feet, only the faint sunlight and
• 25:52
  Speaker 1: the pale surface stretching toward the horizon. Yet beneath that
• 25:56
  Speaker 1: quiet surface, the nitrogen ice is slowly shifting. Material can
• 26:02
  Speaker 1: move from higher ground toward lower regions, creating broad glacier-like flows.
• 26:08
  Speaker 1: The source describes nitrogen ice behaving as a kind of
• 26:12
  Speaker 1: slow-moving glacier, flowing into lower areas and helping reshape Pluto's surface.
• 26:18
  Speaker 1: And across Sputnik Planitia, there are enormous polygonal patterns. From above,
• 26:24
  Speaker 1: they look almost like giant pieces of a softly divided landscape.
• 26:28
  Speaker 1: But these shapes are not simply painted onto the surface.
• 26:32
  Speaker 1: They are connected with slow movement within the nitrogen ice.
• 26:36
  Speaker 1: Warmer material from deeper within the ice can slowly rise.
• 26:41
  Speaker 1: Cooler material can sink. The movement is gentle, continuous, and
• 26:46
  Speaker 1: almost invisible. Scientists call this process convection, but you do
• 26:51
  Speaker 1: not need to imagine anything violent. It is closer to
• 26:55
  Speaker 1: a very slow breathing motion beneath the surface. Upward, downward,
• 27:00
  Speaker 1: again and again. So the frozen plane that looks motionless
• 27:04
  Speaker 1: from a distance is not truly motionless at all. It
• 27:08
  Speaker 1: is changing. Very slowly, so slowly that an entire human
• 27:13
  Speaker 1: life would barely notice the movement. And yet over thousands, millions,
• 27:19
  Speaker 1: perhaps much longer periods of time, those tiny changes can
• 27:23
  Speaker 1: reshape an enormous landscape. This is one of the quiet
• 27:27
  Speaker 1: surprises of Pluto. Cold does not always mean still. A
• 27:32
  Speaker 1: frozen world can have moving glaciers. A plane can renew itself.
• 27:37
  Speaker 1: And an apparently silent surface can carry slow movements beneath it.
• 27:41
  Speaker 1: The heart-shaped region becomes even more beautiful when you think
• 27:45
  Speaker 1: about it this way. It is not merely a bright
• 27:48
  Speaker 1: mark that happens to resemble a heart. It is part
• 27:52
  Speaker 1: of a world that is still changing. A world where
• 27:55
  Speaker 1: ice can travel. A world where the surface can soften
• 27:58
  Speaker 1: ancient scars. A world where the cold itself becomes part
• 28:02
  Speaker 1: of the motion. And as you remain there for a moment,
• 28:06
  Speaker 1: looking across the pale plain, you might begin to notice
• 28:09
  Speaker 1: something else. The surface is not the whole story. Above
• 28:14
  Speaker 1: the ice, Pluto has something even more delicate. An atmosphere.
• 28:18
  Speaker 1: It is so thin and faint that you would hardly
• 28:21
  Speaker 1: know it was there. and yet it rises above this
• 28:24
  Speaker 1: frozen landscape, changing as Pluto follows its long journey around
• 28:28
  Speaker 1: the Sun. The same world that appears silent beneath your
• 28:32
  Speaker 1: feet is quietly releasing material into the darkness above. The
• 28:37
  Speaker 1: ice moves below, the atmosphere moves above, and between them,
• 28:42
  Speaker 1: Pluto continues its slow, almost imperceptible transformation. Above the frozen plane,
• 28:51
  Speaker 1: where the nitrogen ice moves so slowly that you would
• 28:54
  Speaker 1: never notice it from the ground, another kind of movement
• 28:57
  Speaker 1: is taking place. It is almost invisible. There is no
• 29:01
  Speaker 1: blue sky stretching overhead like the one you know on Earth.
• 29:05
  Speaker 1: There are no clouds drifting gently across a warm afternoon.
• 29:09
  Speaker 1: There is hardly any air at all. And yet Pluto
• 29:13
  Speaker 1: does have an atmosphere. It begins quietly, close to the
• 29:17
  Speaker 1: frozen surface. Some of the ice resting on Pluto can
• 29:21
  Speaker 1: respond to the changing warmth of sunlight by becoming gas.
• 29:25
  Speaker 1: There is something unusual about this process. The ice does
• 29:29
  Speaker 1: not have to melt first. It can move directly from
• 29:33
  Speaker 1: a solid state into a gas. Scientists call this process sublimation.
• 29:38
  Speaker 1: But you can simply imagine the surface slowly releasing a
• 29:42
  Speaker 1: little of itself into the darkness. A patch of frozen
• 29:46
  Speaker 1: nitrogen rests beneath the distant sun. The sunlight touches it.
• 29:51
  Speaker 1: Some of the material becomes gas. The gas rises, and
• 29:56
  Speaker 1: for a while, It becomes part of Pluto's extremely thin atmosphere.
• 30:01
  Speaker 1: It is a quiet exchange between the ground and the sky.
• 30:04
  Speaker 1: Ice becomes gas. Gas moves through the atmosphere. And under
• 30:09
  Speaker 1: different conditions, some of that material can eventually return to
• 30:13
  Speaker 1: the surface. The source describes this relationship between Pluto's surface
• 30:17
  Speaker 1: and atmosphere as an ongoing cycle, with nitrogen and other
• 30:22
  Speaker 1: materials moving between frozen ground and the thin air above it.
• 30:27
  Speaker 1: You can imagine the process happening so slowly that Pluto
• 30:30
  Speaker 1: itself seems to breathe, not with lungs, not with anything alive,
• 30:36
  Speaker 1: but with the gentle rise and return of frozen material.
• 30:40
  Speaker 1: The surface gives something to the atmosphere, the atmosphere carries
• 30:44
  Speaker 1: it for a while, and eventually some of it may
• 30:47
  Speaker 1: settle back onto the world. The atmosphere is mostly nitrogen,
• 30:51
  Speaker 1: with smaller amounts of methane and carbon monoxide. These names
• 30:56
  Speaker 1: may sound technical, but they are simply different substances moving
• 31:00
  Speaker 1: through a very cold and distant environment. You do not
• 31:03
  Speaker 1: need to picture formulas or symbols. Just imagine a thin
• 31:07
  Speaker 1: mixture of invisible gases, rising only a little above the surface,
• 31:12
  Speaker 1: before becoming almost indistinguishable from the darkness around Pluto. The
• 31:17
  Speaker 1: atmosphere is so thin that if you were somehow standing
• 31:20
  Speaker 1: there without protection, it would not feel like the air
• 31:23
  Speaker 1: around you on Earth. there would be no familiar breeze,
• 31:27
  Speaker 1: no soft pressure against your skin, no comfortable atmosphere surrounding you. Instead,
• 31:33
  Speaker 1: the world above you would feel almost empty. And yet
• 31:37
  Speaker 1: this almost empty sky can still change. Pluto follows its long,
• 31:42
  Speaker 1: stretched path around the Sun. As its distance from the
• 31:45
  Speaker 1: Sun changes, the amount of sunlight reaching its surface changes
• 31:49
  Speaker 1: as well. When Pluto receives more sunlight, more surface ice
• 31:54
  Speaker 1: can become gas. When conditions become colder, material can settle
• 31:59
  Speaker 1: back toward the surface. So Pluto's atmosphere is not simply
• 32:04
  Speaker 1: sitting there permanently. It can grow and thin. It can move.
• 32:09
  Speaker 1: It can expand outward into space. And because Pluto is
• 32:13
  Speaker 1: a small world, its gravity is not strong enough to
• 32:16
  Speaker 1: hold every molecule forever. Some atmospheric particles can gradually escape.
• 32:23
  Speaker 1: You can picture them drifting upward, becoming more widely separated,
• 32:26
  Speaker 1: until the boundary between Pluto's atmosphere and the surrounding space
• 32:31
  Speaker 1: becomes almost impossible to define. There is no sharp wall
• 32:35
  Speaker 1: where the atmosphere suddenly ends. Instead, it becomes thinner and thinner,
• 32:41
  Speaker 1: a little less and a little less, until there is
• 32:44
  Speaker 1: almost nothing left. Far above the surface, sunlight interacts with
• 32:49
  Speaker 1: tiny particles in this delicate atmosphere. These particles can form
• 32:54
  Speaker 1: layers of haze, and when sunlight passes through those layers,
• 32:58
  Speaker 1: the atmosphere can take on a faint blue appearance. It
• 33:02
  Speaker 1: is not a bright blue sky like Earth. It is softer,
• 33:06
  Speaker 1: more distant, more ghostly. Imagine looking toward the edge of
• 33:10
  Speaker 1: Pluto from the surface. The sun is low and weak.
• 33:15
  Speaker 1: The horizon is dark, and around the edge of the world,
• 33:19
  Speaker 1: a very thin blue line seems to appear. almost as
• 33:22
  Speaker 1: though someone had brushed a little colour around the rim
• 33:25
  Speaker 1: of the frozen planet. The New Horizons spacecraft was able
• 33:29
  Speaker 1: to observe this haze from a different perspective, looking back
• 33:33
  Speaker 1: toward Pluto after passing by. The light travelled through the atmosphere,
• 33:38
  Speaker 1: touched the tiny particles suspended there, and revealed a delicate
• 33:42
  Speaker 1: structure that would have been difficult to notice from the
• 33:45
  Speaker 1: surface alone. For a moment, Pluto did not look completely airless.
• 33:50
  Speaker 1: it looked wrapped in a very thin veil. And this
• 33:54
  Speaker 1: veil connects with another mystery on the surface. The reddish
• 33:57
  Speaker 1: colour you saw earlier is not simply ordinary rock. Far
• 34:02
  Speaker 1: above the surface, sunlight and radiation can slowly alter simple
• 34:06
  Speaker 1: molecules such as methane and carbon dioxide. Over time, more
• 34:12
  Speaker 1: complicated organic material can form. Some of this material is
• 34:16
  Speaker 1: dark and reddish. Scientists call these materials Tholins. The word
• 34:22
  Speaker 1: itself is less important than the slow process behind it.
• 34:25
  Speaker 1: Simple molecules, faint sunlight, radiation, time, and eventually, tiny complex
• 34:33
  Speaker 1: particles with reddish colours. Some of these particles can remain
• 34:37
  Speaker 1: suspended in the atmosphere. Others can slowly settle downward. Over
• 34:42
  Speaker 1: immense periods of time, they may gather across the surface.
• 34:46
  Speaker 1: and this may help create some of Pluto's darker red
• 34:50
  Speaker 1: and brown regions. So the colour of Pluto is connected,
• 34:54
  Speaker 1: in part, to what happens above the surface. The frozen
• 34:58
  Speaker 1: ground is not completely separate from the atmosphere, the atmosphere
• 35:02
  Speaker 1: is not completely separate from space, and space itself is
• 35:06
  Speaker 1: not completely separate from the chemistry taking place on the surface.
• 35:10
  Speaker 1: Everything is gently connected. Ice rises, gas drifts. Light changes molecules,
• 35:17
  Speaker 1: tiny particles form, some eventually fall back down, and the
• 35:22
  Speaker 1: surface slowly receives them. You can let that cycle repeat
• 35:26
  Speaker 1: in your imagination, upward, outward, then downward again, a little
• 35:32
  Speaker 1: material leaving the frozen ground, a little material moving through
• 35:36
  Speaker 1: the thin atmosphere, a little material returning to the world below,
• 35:40
  Speaker 1: all of it happening beneath a distant sun. all of
• 35:43
  Speaker 1: it happening so slowly that Pluto can appear perfectly still.
• 35:48
  Speaker 1: But now, as you look across the pale heart-shaped plane,
• 35:52
  Speaker 1: you know that the surface is moving, you know that
• 35:55
  Speaker 1: material can rise from the ice, you know that the
• 35:58
  Speaker 1: atmosphere can change, and you know that even the reddish
• 36:02
  Speaker 1: colour of the distant landscape may have begun with an
• 36:05
  Speaker 1: invisible process high above your head. Yet there is still
• 36:09
  Speaker 1: something deeper, Because if Pluto can release material from its
• 36:13
  Speaker 1: frozen surface, and if its atmosphere can change with sunlight,
• 36:17
  Speaker 1: then perhaps the most interesting question is not what happens
• 36:21
  Speaker 1: above the ground. Perhaps it is what is happening beneath it,
• 36:25
  Speaker 1: under the nitrogen ice, under the mountains, under the frozen crust.
• 36:30
  Speaker 1: There may be a place where Pluto is not quite
• 36:33
  Speaker 1: as cold as it appears, a hidden region that new
• 36:36
  Speaker 1: horizons could never see directly. And slowly, The quiet world
• 36:41
  Speaker 1: above the ice begins to point downward. For a moment,
• 36:47
  Speaker 1: you can remain beside the pale frozen plane. The surface
• 36:51
  Speaker 1: of Pluto stretches quietly beneath you. The nitrogen ice moves
• 36:56
  Speaker 1: so slowly that it seems still. Above you, the atmosphere
• 37:00
  Speaker 1: is almost weightless. The distant sun provides only a faint light.
• 37:05
  Speaker 1: Everything about Pluto seems to suggest cold. And yet …
• 37:10
  Speaker 1: As New Horizons looked more closely at this distant world,
• 37:14
  Speaker 1: another possibility began to emerge. Perhaps Pluto is not entirely
• 37:19
  Speaker 1: frozen inside. Perhaps somewhere beneath the surface there is still warmth.
• 37:25
  Speaker 1: The first clue comes from the mountains. Not ordinary mountains,
• 37:30
  Speaker 1: shaped only by ancient impacts and frozen erosion, but enormous
• 37:35
  Speaker 1: structures that may have been built by material rising from below.
• 37:40
  Speaker 1: One of the most remarkable is Wright Mons. It rises
• 37:44
  Speaker 1: several kilometres above the surrounding landscape and stretches for roughly
• 37:48
  Speaker 1: 150 kilometres across, according to the supplied source. From a distance,
• 37:55
  Speaker 1: it can look almost like a very broad, gentle mountain,
• 37:59
  Speaker 1: but its shape invites another possibility. Perhaps it was a volcano,
• 38:04
  Speaker 1: not a volcano like the ones you know on Earth.
• 38:07
  Speaker 1: there would be no rivers of glowing red rock flowing
• 38:10
  Speaker 1: down its slopes, no bright fountains of molten material rising
• 38:15
  Speaker 1: into a hot atmosphere. Pluto is far too cold for
• 38:19
  Speaker 1: that familiar picture. Instead, if Wright-Mons is volcanic, the material
• 38:24
  Speaker 1: moving through it would be much colder. A mixture of
• 38:28
  Speaker 1: water ice and other frozen materials may have risen from
• 38:31
  Speaker 1: beneath the surface, forming a kind of cold volcanic flow.
• 38:36
  Speaker 1: This process is called cryovolcanism. The word simply means volcanic
• 38:41
  Speaker 1: activity involving icy or volatile materials, rather than the hot
• 38:46
  Speaker 1: molten rock found in Earth's volcanoes. You can imagine it
• 38:49
  Speaker 1: very gently. Deep below the frozen surface, something moves. It
• 38:55
  Speaker 1: finds a path upward. It slowly reaches the surface, and
• 39:00
  Speaker 1: instead of fire, it leaves behind ice. A mountain made
• 39:04
  Speaker 1: not by burning heat, but by hidden movement beneath a
• 39:08
  Speaker 1: frozen world. The supplied source describes Wright Mons as a
• 39:13
  Speaker 1: large icy volcano, and notes that its surface has relatively
• 39:17
  Speaker 1: few visible impact craters. That absence of craters is important.
• 39:23
  Speaker 1: Just as Sputnik Planitia appears young because its surface has
• 39:27
  Speaker 1: been renewed, a relatively smooth volcanic surface structure can suggest
• 39:31
  Speaker 1: that something has changed it more recently than the surrounding
• 39:34
  Speaker 1: ancient terrain. But here, it is important to remain gentle
• 39:38
  Speaker 1: with what we know. We do not know exactly how
• 39:41
  Speaker 1: often such activity might occur. We do not know whether
• 39:45
  Speaker 1: Wright Mons is erupting today. and we should not imagine
• 39:48
  Speaker 1: a schedule of eruptions unfolding beneath Pluto. Instead, the evidence
• 39:54
  Speaker 1: suggests something quieter. Pluto has features that may have been
• 39:58
  Speaker 1: formed or renewed by internal activity. And that raises a
• 40:02
  Speaker 1: deeper question. Where could the energy come from? Pluto is small.
• 40:07
  Speaker 1: It is far from the Sun. Its surface is extremely cold.
• 40:11
  Speaker 1: And yet the evidence described in the source suggests that
• 40:14
  Speaker 1: its interior may still retain heat. That is a strange thought.
• 40:19
  Speaker 1: You can imagine touching the frozen surface of Pluto, feeling
• 40:23
  Speaker 1: nothing but cold beneath your imagined feet. Then imagine moving downward,
• 40:28
  Speaker 1: through the nitrogen-rich surface, through layers of harder ice, deeper
• 40:34
  Speaker 1: and deeper. The light from the sun disappears, the surface
• 40:38
  Speaker 1: becomes distant. And somewhere below, there may be warmth. Not
• 40:43
  Speaker 1: warmth like a summer afternoon, not a glowing furnace. just
• 40:47
  Speaker 1: enough internal energy to keep parts of Pluto from becoming
• 40:51
  Speaker 1: completely frozen and still. Scientists have considered the possibility that
• 40:56
  Speaker 1: liquid water could exist beneath Pluto's frozen outer layers. The
• 41:01
  Speaker 1: supplied source describes a possible thick layer of liquid water
• 41:05
  Speaker 1: below the surface, based on the evidence and interpretation presented there.
• 41:10
  Speaker 1: It is important to call this what it is, a possibility.
• 41:15
  Speaker 1: A hidden ocean has not been directly seen. No spacecraft
• 41:19
  Speaker 1: has drilled through Pluto's crust. New horizons passed by too
• 41:23
  Speaker 1: quickly and too far above the surface to look directly
• 41:27
  Speaker 1: into Pluto's interior. Instead, scientists look at the clues on
• 41:31
  Speaker 1: the surface. Mountains, plains, the apparent youth of certain regions,
• 41:38
  Speaker 1: structures that may have formed through internal activity. Together, These
• 41:43
  Speaker 1: clues allow scientists to ask whether Pluto might contain liquid
• 41:47
  Speaker 1: water beneath its frozen exterior. And this possibility connects Pluto
• 41:52
  Speaker 1: with another family of distant worlds. Some icy moons around
• 41:57
  Speaker 1: the giant planets are also thought to contain water beneath
• 42:00
  Speaker 1: thick layers of ice. Europa, orbiting Jupiter, is one familiar example.
• 42:07
  Speaker 1: Other icy worlds may have similar hidden environments, but Pluto
• 42:11
  Speaker 1: is different. those moons can experience strong gravitational interactions with
• 42:16
  Speaker 1: their giant planets, which can provide a source of internal heating.
• 42:20
  Speaker 1: Pluto does not have a giant planet nearby in the
• 42:23
  Speaker 1: same way, so one of the quiet mysteries remains. If
• 42:27
  Speaker 1: Pluto really does retain significant internal warmth, where did that
• 42:32
  Speaker 1: warmth come from? The supplied source does not provide a
• 42:35
  Speaker 1: definitive answer. Perhaps some of Pluto's original heat from the
• 42:39
  Speaker 1: early solar system has survived. Perhaps radioactive materials deep inside
• 42:44
  Speaker 1: the world have released energy slowly over immense periods of time.
• 42:49
  Speaker 1: Perhaps other processes are involved. For now, the answer remains uncertain.
• 42:55
  Speaker 1: And there is something strangely peaceful about that uncertainty. You
• 42:59
  Speaker 1: do not need to solve it. You can simply let
• 43:02
  Speaker 1: the question remain beneath the ice. Because Pluto has been
• 43:06
  Speaker 1: carrying that question for billions of years. While its surface
• 43:10
  Speaker 1: travels around the sun, while nitrogen glaciers slowly move across
• 43:14
  Speaker 1: Sputnik Planitia, while thin gases rise into the darkness, the
• 43:19
  Speaker 1: interior may continue its quiet work far below. A frozen surface,
• 43:24
  Speaker 1: a hidden warmth, perhaps even a layer of dark liquid water,
• 43:29
  Speaker 1: and above all of it, the almost complete silence of space.
• 43:33
  Speaker 1: You can imagine standing once more on the surface, looking
• 43:37
  Speaker 1: across right mons. The mountain is cold, the plain is cold,
• 43:42
  Speaker 1: the sky is cold. Everything around you appears frozen, yet
• 43:47
  Speaker 1: somewhere beneath your feet something may still be moving, something
• 43:50
  Speaker 1: may still be releasing heat, something may still be changing
• 43:54
  Speaker 1: Pluto from within. And perhaps the strangest part is that
• 43:58
  Speaker 1: this hidden activity may not belong entirely to Pluto alone,
• 44:02
  Speaker 1: because very close beside Pluto, moving with it through the darkness,
• 44:07
  Speaker 1: is another world. Charon, and the relationship between these two
• 44:12
  Speaker 1: worlds may reach much deeper than simply sharing the same orbit.
• 44:18
  Speaker 1: For a little while you can remain beneath the quiet
• 44:22
  Speaker 1: sky of Pluto. The mountains are behind you. The pale
• 44:26
  Speaker 1: plain stretches toward the horizon. Somewhere beneath the frozen ground
• 44:31
  Speaker 1: there may be warmth. Perhaps there is even water hidden
• 44:35
  Speaker 1: beneath layers of ice. And above everything The faint atmosphere
• 44:39
  Speaker 1: drifts almost imperceptibly into space. But Pluto has never been
• 44:44
  Speaker 1: completely alone. Just beyond the horizon, moving with it through
• 44:48
  Speaker 1: the darkness, is Charon. The two worlds remain close. They
• 44:53
  Speaker 1: turn together, they show each other the same faces, and
• 44:57
  Speaker 1: they move around an invisible point between them, as though
• 45:01
  Speaker 1: their shared gravity has given them a single, slow rhythm.
• 45:05
  Speaker 1: The arrangement is unusual enough. that scientists have wondered whether
• 45:09
  Speaker 1: Pluto and Charon may have a common history. One possibility
• 45:13
  Speaker 1: is that the two worlds were shaped by a very
• 45:16
  Speaker 1: ancient collision. This idea is not something New Horizons directly witnessed.
• 45:23
  Speaker 1: The spacecraft arrived billions of years too late for that. Instead,
• 45:28
  Speaker 1: scientists examine the present arrangement of Pluto and Charon and
• 45:33
  Speaker 1: ask what kind of history could have produced it. You
• 45:36
  Speaker 1: can imagine the young solar system as a much more
• 45:39
  Speaker 1: crowded place than the quiet darkness you see now. Worlds
• 45:43
  Speaker 1: were forming. Small bodies were moving through the outer regions.
• 45:48
  Speaker 1: Gravity was constantly rearranging their paths. Objects could approach one another,
• 45:54
  Speaker 1: pass by, or sometimes collide. And somewhere in that ancient darkness,
• 46:00
  Speaker 1: Pluto and Charon may have encountered one another. Perhaps the
• 46:04
  Speaker 1: meeting was violent by human standards. But on the scale
• 46:08
  Speaker 1: of worlds, the result may have been more complicated than
• 46:11
  Speaker 1: simple destruction. Instead of one body disappearing and another remaining,
• 46:17
  Speaker 1: the two may have become gravitationally bound. Pluto remained. Charon remained.
• 46:23
  Speaker 1: And together, they continued through the solar system. The supplied
• 46:27
  Speaker 1: source presents this collision as a possible origin for their
• 46:31
  Speaker 1: unusual configuration. and suggests that the encounter may also have
• 46:35
  Speaker 1: influenced Pluto's later internal activity. It is important to leave
• 46:41
  Speaker 1: the word possible in place. You do not need to
• 46:45
  Speaker 1: turn the idea into certainty. There is something more beautiful
• 46:49
  Speaker 1: in allowing the ancient history to remain partly hidden. After all,
• 46:54
  Speaker 1: Pluto and Charon have been carrying their secrets for billions
• 46:58
  Speaker 1: of years. You can imagine the two young worlds after
• 47:01
  Speaker 1: their encounter. Perhaps Pluto was left with a changed interior.
• 47:06
  Speaker 1: Perhaps Charon settled into a close orbit, and over an
• 47:10
  Speaker 1: immense amount of time, gravity slowly did the rest. It
• 47:14
  Speaker 1: brought their rotations into harmony. It kept them close. It
• 47:18
  Speaker 1: created the shared movement we see today. Now, imagine standing
• 47:24
  Speaker 1: on Pluto again. Look upward. Charon is there. Not rising.
• 47:29
  Speaker 1: Not setting. Just present. A large companion hanging in one
• 47:34
  Speaker 1: place in the sky. Its surface is different from Pluto's.
• 47:39
  Speaker 1: It is brighter in some regions, darker in others, and
• 47:42
  Speaker 1: marked by long valleys and broad landscapes of its own.
• 47:46
  Speaker 1: But there is one detail that seems especially interesting. Charon
• 47:51
  Speaker 1: has a reddish region near one of its poles, a darker,
• 47:55
  Speaker 1: rusty-looking area, and the colour invites another quiet question. Where
• 48:00
  Speaker 1: did it come from? One possibility discussed in the supplied
• 48:03
  Speaker 1: material is that some of the reddish material on Charon
• 48:07
  Speaker 1: may have originated on Pluto. You can imagine tiny particles
• 48:12
  Speaker 1: leaving Pluto, not great clouds, not enormous explosions, just small
• 48:18
  Speaker 1: pieces of material escaping from the surface and entering the
• 48:21
  Speaker 1: space between the two worlds. Some material produced through radiation-driven
• 48:27
  Speaker 1: chemistry may become dark and reddish. These materials are called tholins,
• 48:32
  Speaker 1: can accumulate on surfaces over long periods of time. If
• 48:37
  Speaker 1: some particles were able to escape Pluto's relatively weak gravity,
• 48:41
  Speaker 1: they could travel outward. And because Charon is nearby, some
• 48:45
  Speaker 1: of that material might eventually reach its surface. You can
• 48:49
  Speaker 1: picture it almost like an extremely slow snowfall across space.
• 48:54
  Speaker 1: No flakes, no wind, no sound. Only tiny particles moving
• 48:59
  Speaker 1: through darkness. some drifting away, some remaining near Pluto, and
• 49:05
  Speaker 1: some perhaps settling onto Charon. Over enormous periods of time,
• 49:09
  Speaker 1: a very small amount of material could gradually become visible,
• 49:13
  Speaker 1: a faint reddish coating, a subtle colour near the pole,
• 49:18
  Speaker 1: a trace of one world appearing on a It is
• 49:21
  Speaker 1: an intriguing possibility, but again, it remains an interpretation rather
• 49:26
  Speaker 1: than a directly observed journey of individual particles from Pluto
• 49:30
  Speaker 1: to Charon. New horizons could photograph the surfaces. It could
• 49:35
  Speaker 1: measure their properties. It could observe the colours and structures.
• 49:40
  Speaker 1: but it could not watch one tiny particle leave Pluto
• 49:43
  Speaker 1: and land on Charon. So the connection remains something scientists
• 49:47
  Speaker 1: investigate through evidence. And perhaps that uncertainty makes the two
• 49:51
  Speaker 1: worlds even more interesting. Because when you look at Pluto
• 49:55
  Speaker 1: and Charon together, you are not simply looking at a
• 49:58
  Speaker 1: planet and its moon. You may be looking at two
• 50:01
  Speaker 1: worlds whose histories are intertwined. One world may have influenced
• 50:05
  Speaker 1: the other. Material may have crossed the space between them.
• 50:09
  Speaker 1: Their gravity has shaped their motion, and perhaps an ancient
• 50:13
  Speaker 1: encounter changed the interiors of both. They are separated by
• 50:18
  Speaker 1: thousands of kilometres. Yet, in a cosmic sense, they are
• 50:22
  Speaker 1: remarkably close. And the closer you look, the harder it
• 50:26
  Speaker 1: becomes to think of either world entirely by itself. Pluto's
• 50:31
  Speaker 1: heart-shaped region may have a connection to its ancient history.
• 50:36
  Speaker 1: Charon's position may reflect the same history. Their shared motion
• 50:40
  Speaker 1: may be a long-lasting memory of an encounter that happened
• 50:43
  Speaker 1: before Earth had taken its modern form. Everything you see
• 50:47
  Speaker 1: now is the quiet remainder of something enormously old. The mountains,
• 50:53
  Speaker 1: the plains, the ice, the atmosphere, the reddish material, the
• 50:59
  Speaker 1: slow turning of Pluto and Charon around their shared point.
• 51:03
  Speaker 1: All of it continues, and perhaps that is what makes
• 51:06
  Speaker 1: distant worlds so peaceful to imagine. They do not need
• 51:10
  Speaker 1: you to understand everything. They simply continue. For billions of years,
• 51:15
  Speaker 1: Pluto has followed its long path around the Sun. For
• 51:19
  Speaker 1: billions of years, Charon has followed alongside it. And now,
• 51:24
  Speaker 1: after new horizons pass through their system, these two worlds
• 51:28
  Speaker 1: are no longer completely unknown to you. You have seen
• 51:31
  Speaker 1: their surfaces. You have imagined their atmosphere. You have wandered
• 51:36
  Speaker 1: across their frozen planes. You have looked beneath the ice,
• 51:40
  Speaker 1: and now you can look between them. There is nothing
• 51:43
  Speaker 1: there but darkness. Yet that darkness is not empty of meaning.
• 51:48
  Speaker 1: It is the space where two worlds balance. The space
• 51:51
  Speaker 1: through which tiny particles may drift. The space that has
• 51:55
  Speaker 1: held their shared history for billions of years. And as
• 51:59
  Speaker 1: you remain there quietly, another thought begins to appear. New
• 52:04
  Speaker 1: Horizons did not stop at Pluto. After passing this distant
• 52:08
  Speaker 1: pair of worlds, the spacecraft continued onward. Beyond Pluto was
• 52:12
  Speaker 1: another region, a region filled with small, ancient objects, faint worlds,
• 52:18
  Speaker 1: and countless pieces of the solar system that we had
• 52:20
  Speaker 1: barely begun to see, and so the darkness ahead was
• 52:24
  Speaker 1: still waiting. And so, after everything you have seen on Pluto,
• 52:31
  Speaker 1: you can slowly allow the little world to become smaller again.
• 52:36
  Speaker 1: The pale heart begins to recede. The mountains become softer
• 52:40
  Speaker 1: against the horizon. Charon becomes a smaller companion beside Pluto.
• 52:46
  Speaker 1: And New Horizons continues onward. The spacecraft does not remain there.
• 52:51
  Speaker 1: It does not settle into orbit. It does not wait
• 52:54
  Speaker 1: beside Pluto for another season or another year. After its
• 52:59
  Speaker 1: brief encounter with the Pluto system in July of 2015…
• 53:03
  Speaker 1: New horizons continued deeper into the Kuiper Belt, carrying with
• 53:08
  Speaker 1: it the observations of a world that had remained almost
• 53:11
  Speaker 1: entirely unknown until that moment. You can imagine Pluto slowly
• 53:16
  Speaker 1: disappearing behind you. Not suddenly. There is no final curtain.
• 53:21
  Speaker 1: There is simply distance. A little more distance, then more,
• 53:26
  Speaker 1: and more, until the world that once seemed enormous becomes
• 53:29
  Speaker 1: another small point of light. Ahead lies the Kuiper Belt.
• 53:34
  Speaker 1: This is the region beyond Neptune, a broad, distant zone
• 53:39
  Speaker 1: containing many icy bodies left over from the formation of
• 53:43
  Speaker 1: the solar system. NASA describes it as a large region
• 53:47
  Speaker 1: of icy objects extending far beyond Neptune's orbit, with potentially
• 53:53
  Speaker 1: millions of other small worlds remaining there. So Pluto was
• 53:58
  Speaker 1: never truly alone. It belongs to a much larger family,
• 54:02
  Speaker 1: And perhaps this changes the way you think about it.
• 54:05
  Speaker 1: Pluto was once imagined as the final planet, the little
• 54:09
  Speaker 1: world sitting at the edge of everything. But now you
• 54:12
  Speaker 1: know that the edge is not really an edge. Beyond Pluto,
• 54:17
  Speaker 1: there are more worlds, more pieces of ancient material, more
• 54:22
  Speaker 1: objects moving quietly through the darkness. And most of them
• 54:26
  Speaker 1: have never been visited by a spacecraft. Only one spacecraft
• 54:30
  Speaker 1: has explored the Kuiper Belt up close. New Horizons. And
• 54:35
  Speaker 1: even after Pluto, its journey continued. In 2019, the spacecraft
• 54:42
  Speaker 1: reached another Kuiper Belt object. Its name is Arrokoth. It
• 54:47
  Speaker 1: was the most distant object ever explored up close at
• 54:50
  Speaker 1: the time of the encounter, roughly a billion miles beyond Pluto.
• 54:55
  Speaker 1: Arrokoth was very different from Pluto. It was much smaller.
• 55:00
  Speaker 1: It did not have a vast atmosphere like Pluto's. It
• 55:04
  Speaker 1: did not have a great heart-shaped plane. But it offered
• 55:07
  Speaker 1: something else. A glimpse of an ancient object that had
• 55:11
  Speaker 1: remained far from the warmer inner solar system for almost
• 55:14
  Speaker 1: all of its history. You can imagine approaching it slowly.
• 55:19
  Speaker 1: At first, Arrokoth would have been nothing more than a
• 55:22
  Speaker 1: tiny point. Then a shape. Then two connected lobes. a
• 55:27
  Speaker 1: strange reddish-brown world floating quietly in the darkness. And suddenly,
• 55:33
  Speaker 1: the distant Kuiper Belt was no longer just a concept.
• 55:37
  Speaker 1: It was a place, a place containing actual landscapes, actual surfaces,
• 55:43
  Speaker 1: actual ancient worlds. The same is true of Pluto. Before
• 55:48
  Speaker 1: New Horizons arrived, Pluto was mostly an idea in your mind.
• 55:53
  Speaker 1: A name, a small point of light, a distant object
• 55:57
  Speaker 1: measured through telescopes. But when the spacecraft passed by, that
• 56:02
  Speaker 1: point became a landscape. And perhaps this is one of
• 56:05
  Speaker 1: the most beautiful things about exploration. Sometimes the greatest discovery
• 56:11
  Speaker 1: is not finding something completely unexpected. Sometimes it is discovering
• 56:16
  Speaker 1: that something you thought you understood is far more complicated
• 56:20
  Speaker 1: than you imagined. Pluto became larger in our minds because
• 56:25
  Speaker 1: it became smaller in our images. We could finally see
• 56:29
  Speaker 1: its surface. We could see its mountains, its glaciers, its atmosphere,
• 56:35
  Speaker 1: its colours, its possible cryovolcanoes, its relationship with Charon, and
• 56:41
  Speaker 1: perhaps the hidden water beneath the ice. All of those
• 56:44
  Speaker 1: discoveries came from a brief encounter, a spacecraft moving quickly
• 56:49
  Speaker 1: through the system, a few precious hours of close observation. Then,
• 56:54
  Speaker 1: Once again, distance. New Horizons continued outward, and even today,
• 57:00
  Speaker 1: the spacecraft remains active in the far reaches of the
• 57:04
  Speaker 1: solar system. NASA has continued extending the mission, using New
• 57:09
  Speaker 1: Horizons to study the distant space environment and the Kuiper
• 57:13
  Speaker 1: Belt while searching for opportunities for further close encounters. NASA's
• 57:18
  Speaker 1: current mission information says the spacecraft is expected to remain
• 57:23
  Speaker 1: within the Kuiper Belt into roughly 2028 or 2029. So
• 57:30
  Speaker 1: the story did not truly end at Pluto. The spacecraft
• 57:34
  Speaker 1: simply kept going, farther from Earth, farther from the Sun,
• 57:39
  Speaker 1: farther from the familiar worlds. The Sun itself becomes increasingly faint.
• 57:45
  Speaker 1: From New Horizons' distant position, our star is no longer
• 57:48
  Speaker 1: the enormous glowing presence you imagine from Earth. It is
• 57:52
  Speaker 1: simply the star at the centre of the solar system,
• 57:56
  Speaker 1: still providing a little light, still holding the distant worlds
• 57:59
  Speaker 1: in its gravitational influence. And around New Horizons there is
• 58:04
  Speaker 1: almost nothing. No air, no wind, no sound. Only the
• 58:09
  Speaker 1: faint particles of space, distant sunlight, and the slow movement
• 58:14
  Speaker 1: of a machine, carrying traces of human curiosity outward. You
• 58:19
  Speaker 1: can imagine the spacecraft continuing through that darkness now. Behind it,
• 58:24
  Speaker 1: Pluto is becoming smaller. Farther behind, Neptune. Farther still, the
• 58:30
  Speaker 1: familiar planets. Earth has already become unimaginably distant. Yet somewhere
• 58:37
  Speaker 1: on that small blue world, people are still looking outward,
• 58:41
  Speaker 1: still wondering, still asking what lies beyond the next horizon.
• 58:46
  Speaker 1: And perhaps Pluto has left you with a quieter answer
• 58:48
  Speaker 1: than you expected. A world does not have to be
• 58:51
  Speaker 1: large to be complicated. It does not have to be
• 58:55
  Speaker 1: warm to be active. It does not have to be
• 58:57
  Speaker 1: close to the sun to contain movement. And it does
• 59:01
  Speaker 1: not have to keep the name planet to remain extraordinary.
• 59:05
  Speaker 1: Pluto is a small frozen world, but beneath its pale
• 59:08
  Speaker 1: surface ice can move. Above it, an atmosphere can rise
• 59:13
  Speaker 1: and fade. Across it, colours can form slowly through chemistry
• 59:17
  Speaker 1: and sunlight. Within it, there may be warmth, perhaps water,
• 59:22
  Speaker 1: perhaps ancient geological activity. And beside it, Charon continues its
• 59:27
  Speaker 1: patient turning. sharing the same invisible gravitational rhythm. Beyond Pluto,
• 59:34
  Speaker 1: countless other worlds wait in the Kuiper belt. Most have
• 59:38
  Speaker 1: never been seen closely, some may be smaller, some may
• 59:42
  Speaker 1: be darker, some may have histories even stranger than Pluto's.
• 59:47
  Speaker 1: And perhaps, far in the future, another spacecraft will travel
• 59:51
  Speaker 1: through this darkness and turn another tiny point of light
• 59:55
  Speaker 1: into a landscape. For now, You can simply let new
• 59:59
  Speaker 1: horizons continue. You do not need to follow it. You
• 1:00:03
  Speaker 1: do not need to know where every distant world is.
• 1:00:07
  Speaker 1: You can let the spacecraft become smaller and smaller, drifting
• 1:00:10
  Speaker 1: outward through the quiet frontier, and behind it, Pluto remains there,
• 1:00:16
  Speaker 1: still turning, still following its long path around the Sun,
• 1:00:20
  Speaker 1: still carrying its frozen heart, its moving ice, its thin atmosphere,
• 1:00:26
  Speaker 1: and its hidden questions. The little world that once seemed
• 1:00:29
  Speaker 1: to be the end of the solar system was never
• 1:00:32
  Speaker 1: really the end. It was simply one quiet doorway into
• 1:00:35
  Speaker 1: a much larger darkness. And beyond that doorway, the Kuiper
• 1:00:40
  Speaker 1: Belt continues. Cold, ancient, mostly unseen, and very, very quiet.
• 1:00:50
  Speaker 1: And so, our journey through Pluto can slowly come to rest.
• 1:00:54
  Speaker 1: You have travelled across a frozen heart, beneath a faint
• 1:00:58
  Speaker 1: blue haze, and through landscapes where nitrogen ice moves almost
• 1:01:02
  Speaker 1: too slowly to notice. You have watched Pluto and Charon
• 1:01:07
  Speaker 1: turning together in the darkness, two distant worlds sharing an
• 1:01:11
  Speaker 1: invisible rhythm, perhaps carrying the quiet traces of an ancient encounter.
• 1:01:16
  Speaker 1: You have drifted above mountains that may have been shaped
• 1:01:19
  Speaker 1: by icy volcanic activity, and imagined what might exist beneath
• 1:01:23
  Speaker 1: the frozen crust. perhaps a hidden layer of water, perhaps
• 1:01:28
  Speaker 1: only warmth slowly fading through the deep interior. And now,
• 1:01:33
  Speaker 1: you can let all of those images become softer. There
• 1:01:36
  Speaker 1: is nothing more you need to understand tonight. You do
• 1:01:39
  Speaker 1: not need to remember the names of the mountains, the glaciers,
• 1:01:43
  Speaker 1: the plains, or the distant spacecraft. You can simply let
• 1:01:47
  Speaker 1: Pluto become a small, pale world somewhere far away. New
• 1:01:52
  Speaker 1: Horizons has continued onward, deeper into the quiet frontier beyond Neptune,
• 1:01:58
  Speaker 1: while Pluto remains on its enormous journey around the Sun.
• 1:02:03
  Speaker 1: 248 years for one slow revolution. So much time for
• 1:02:07
  Speaker 1: a world that seems so small. And perhaps somewhere in
• 1:02:11
  Speaker 1: that darkness, the thin atmosphere is still drifting, nitrogen ice
• 1:02:16
  Speaker 1: is still moving across the frozen plain, and tiny particles
• 1:02:20
  Speaker 1: are still settling quietly onto the surface. Everything continues. slowly,
• 1:02:26
  Speaker 1: almost imperceptibly. You are safe here, there is nothing to do,
• 1:02:31
  Speaker 1: just listen, breathe gently, and allow the distance to grow.
• 1:02:36
  Speaker 1: The sun is becoming smaller behind you now, Pluto is
• 1:02:40
  Speaker 1: becoming smaller too, its heart-shaped plane fades into darkness. Charon
• 1:02:46
  Speaker 1: becomes only a faint companion, and eventually both worlds become
• 1:02:51
  Speaker 1: little points of light among countless others. Yet they are
• 1:02:54
  Speaker 1: still there, still turning, still moving, still carrying their ancient
• 1:03:00
  Speaker 1: stories through the cold. And as you drift farther away,
• 1:03:04
  Speaker 1: perhaps you can imagine new horizons continuing ahead, silently crossing
• 1:03:09
  Speaker 1: the Kuiper Belt, toward worlds that we have not yet
• 1:03:12
  Speaker 1: seen closely, toward distant places that may remain unknown for
• 1:03:17
  Speaker 1: many years. The darkness ahead does not need to be filled.
• 1:03:21
  Speaker 1: It can simply remain dark, quiet. open, endless. And somewhere
• 1:03:27
  Speaker 1: far behind you, Pluto continues its slow orbit, holding its
• 1:03:32
  Speaker 1: frozen secrets beneath the faint light of the sun. You
• 1:03:35
  Speaker 1: can let yourself drift now. The stars will remain, the
• 1:03:40
  Speaker 1: planets will continue turning, Pluto will keep moving through the
• 1:03:44
  Speaker 1: distant darkness, and while you sleep, the universe will carry
• 1:03:48
  Speaker 1: on quietly around you.