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Uranus and Neptune – The Forgotten Ice Giants · Talking Science

0:00
Think about the last thing you owned that you
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genuinely just forgot existed. Oh, like something
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shoved way in the back of a closet. Yeah, exactly.
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Like behind the winter coats. Or maybe, you know,
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an old box of random cables. Right, right. We
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all have that one box. We do. And when you finally
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rediscover it, it feels like an artifact from
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someone else's life. Yeah, it really does. Well,
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believe it or not, that exact feeling of neglect
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applies to our very own solar system. Because
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today... For this deep dive, we are heading out
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to the cosmic cupboard. I love that analogy,
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the cosmic cupboard. Right. We're going way out
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past Jupiter, past Saturn to Uranus and Neptune.
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The forgotten planets. Literally the forgotten
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planets because, I mean, the timeline of our
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exploration out there is... Well, it's kind of
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staggering. It genuinely is staggering. I mean,
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the last time a human -built spacecraft flew
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past Uranus was January of 1986. 1986. Yeah.
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And the last time anything visited Neptune was
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August of 1989. Wow. Since then, absolutely nothing
1:01
has been back. That's over three and a half decades
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of just total radio silence, which is crazy when
1:08
you think about it because every other planet
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has had multiple visitors. Oh, yeah. Orbiters,
1:12
landers, rovers. Right. Mars practically has
1:15
a traffic jam at this point. It really does.
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Some planets even have these permanent robotic
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residents just quietly gathering decades of data.
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But Uranus and Neptune, they had one brief flyby
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each, just one, from a single aging spacecraft
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called Voyager 2. Which is wild when you consider
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the technology involved. I mean, the equipment
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Voyager 2 used to capture and... you know, transmit
1:40
those images back to Earth. It was roughly as
1:42
sophisticated as an original Nintendo console.
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Wait, really? A Nintendo? Yeah. That single fleeting
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road trip using 1970s technology, by the way,
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is essentially the sum total of everything we
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know about them up close. That is just mind blowing.
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So to you listening, if you think you know the
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solar system from, you know, those grade school
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dioramas you built as a kid, prepare yourself.
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Yep. Time to update the textbooks. Exactly. These
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two dim blue -green dots are about to completely
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shatter. are your assumptions? Absolutely. But
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before we get into their bizarre weather or like
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their totally weird orbits, we have to understand
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what these planets actually are. Because I don't
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know about you, but I grew up learning that Jupiter,
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Saturn, Uranus and Neptune were all just, well,
2:25
gas giants. Right. And that is a very common
2:28
misconception. We really need to clear that up
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right away. OK, so they aren't gas giants. Well.
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Jupiter and Saturn truly are gas giants. They
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are overwhelmingly made of hydrogen and helium.
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Which is the exact same stuff that makes up the
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sun. Exactly. The same light elements. But Uranus
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and Neptune, they're in a completely different
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category. Planetary scientists actually call
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them ice giants. Ice giants. Okay, let's unpack
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this because calling them ice giants feels like
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a bit of a trick name to me. How so? Well, when
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I hear the word ice, I immediately picture like...
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Glaciers. Or at least a really solid ice cube.
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Right, you're picturing something phrasin solid.
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Yeah, but that's not what's happening inside
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these planets at all, is it? Not at all, no.
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Planetary scientists use the word ices as sort
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of a chemical shorthand. Shorthand for what?
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Well, in astronomy, an ice, or sometimes they
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call it a volatile... It simply refers to compounds
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like water, ammonia, and methane. These are chemicals
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that vaporize relatively easily compared to,
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say, rock and metal. Got it. So it's not about
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them being frozen like a popsicle. Exactly. In
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the early days of the solar system, when everything
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was just this swirling, dusty disk around the
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young sun, these specific compounds were super
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abundant in the outer colder regions. Out where
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Uranus and Neptune are. Right. So those two planets
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just gobbled them up. But wait, I'm getting kind
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of stuck on the physics here. Okay, lay it on
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me. Deep inside Uranus and Neptune, you have
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crushing gravity, right? Like millions of times
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the atmosphere pressure of Earth. Oh, yeah. Unafathomable
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pressure. And searing heat from the planetary
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core. Heat that would instantly vaporize an actual
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ice cube. Correct. So how on Earth can you have
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an ice giant that is scourging hot? That is the
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million -dollar question. And the answer is that
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under that extreme pressure and temperature...
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These materials don't behave like anything we
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interact with here on Earth. Okay, so what do
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they do? They exist in what physicists call a
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supercritical state. Supercritical state. What
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does that actually mean? Well, instead of being
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a solid chunk of ice or, you know, a cloud of
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steam, imagine a hot... incredibly dense, electrically
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conducting fluid soup. A fluid soup. Yeah. The
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sheer pressure forces the molecules together
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so tightly that the boundary between liquid and
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gas completely breaks down. Wow. Okay, so you
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just have these two massive planets filled with
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a hot, churning fluid soup of water, ammonia,
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and methane. Precisely. That completely changes
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how I picture them. It's totally alien to our
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everyday experience. It really is. And, you know,
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because of how they formed out there. the chaos
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of the early solar system, they got battered
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around quite a bit. Oh, they definitely had a
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rough neighborhood. Which brings us to Uranus,
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easily the most visually bizarre trait of any
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planet we know of. It really stands out the moment
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you look at a scale diagram of our solar system.
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Yeah, because every other major planet spins
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on an axis that is... Roughly upright. Right.
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Relative to its orbit around the sun. Right.
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Like Earth is tilted a bit, which is why we have
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summer and winter. But Uranus is tilted by roughly
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98 degrees. 98 degrees. It's basically sideways.
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I always try to picture it for people like this.
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Imagine all the other planets as spinning globes
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standing more or less upright on a tabletop.
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Okay. I'm picturing it. Uranus is a globe that
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has been knocked completely over and it's just
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rolling along the table like a bowling ball.
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That's a perfect analogy. But why? Did something
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just crash into it and knock it over? Well, the
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leading explanation is exactly that. A colossal,
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violent impact early in the solar system's history.
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Just a cosmic hit and run. Pretty much. The model
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suggests Uranus was struck by another protoplanet,
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possibly something, you know, two to three times
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the mass of Earth. Two to three times Earth.
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That is huge. Massive. A collision that large
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would literally rewrite the planet's rotation,
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knocking the entire globe on its side and sending
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all this debris flying out into orbit. Okay,
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but let me play devil's advocate for a second
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here. Go for it. Nobody was there with a telescope
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billions of years ago. Very true. So are we just
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guessing? I mean, how do we actually know that
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happened? It's a really fair challenge. Obviously,
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we can't observe the past directly. So instead,
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physicists use supercomputers to run thousands
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of impact simulations. Oh, like they build a
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digital version of it. Exactly. They plug in
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different sizes of impactors, different angles,
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different speeds. And what do they find? The
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simulations show that a glancing blow from an
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Earth -sized object not only perfectly reproduces
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that exact 98 -degree tilt, but it also explains
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why Uranus's moons orbit around its tilted equator
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rather than the sun's equator. Oh, wow. So the
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physics essentially match the crime scene. Perfectly.
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It's our best, most well -supported model. And
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the consequence of that impact is just staggering
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to think about because it takes Uranus 84...
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Earth years to orbit the sun, right? Four years,
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yes. And since it's rolling on its side, the
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seasons must be unfathomable. They are extreme.
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Basically, each pole gets pointed almost directly
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at the sun for a quarter of its orbit. Okay,
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so wait, a quarter of 84? That means 21 continuous
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years of unbroken sunlight. Just daylight for
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two decades. Yep. Followed immediately by 21
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continuous years of total freezing darkness.
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21 years of pitch black. What does that even
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do to a planet's atmosphere? It's intense. I
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mean, an entire hemisphere is just radiating
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whatever heat it has into the void of space for
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two solid decades. The atmospheric flow must
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just stagnate completely. It's just a great point,
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and it might actually explain why Uranus appears
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so unusually calm and featureless compared to
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the other giants. It's just frozen in place almost.
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Kind of, yeah. But, you know, while Uranus's
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oddities are highly visual, like you can physically
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see it rolling on its side... Neptune's story
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begins in a totally different way. Oh, I love
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this part. It begins as a ghost, right? Yes,
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a literal ghost in the mathematics of Uranus's
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orbit. This is genuinely one of my favorite stories
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in all of science. It's a classic. So early 19th
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century, right? Astronomers were carefully tracking
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Uranus, taking these meticulous notes on exactly
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where it was in the sky. Very precise measurements.
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Right. And something simply wasn't adding up.
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Uranus kept drifting slightly away from where
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Isaac Newton's laws of gravity predicted it should
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be. And you have to understand, this was a massive
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crisis for physics at the time. Because Newton
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was, like, untouchable. Exactly. Newton's laws
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were the gold standard. I mean, they explained
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falling apples and orbiting moons flawlessly.
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But Uranus wasn't behaving. No, it was moving
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a little too fast at certain points in its orbit
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and a little too slow at others. So rather than
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throwing their hands up and just assuming, you
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know, Newton was wrong, two mathematicians took
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this massive leap of faith. Right. Working completely
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independently, too. John Couch Adams in England
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and Urbain Le Verrier in France. Yes. They decided
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the math wasn't wrong. The map was just incomplete.
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I love that. So what was their theory? They reasoned
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that the discrepancy could be perfectly explained
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by the gravitational tug of another unseen planet
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further out in the darkness. Just lurking out
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there. Exactly. Imagine Uranus and this hypothetical
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planet on a racetrack. Okay. As Uranus catches
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up to the slower outer planet, that unseen mass
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pulls Uranus forward, speeding it up slightly.
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Right. A little gravitational boost. But once
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Uranus passes it, that same gravity pulls it
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backward, slowing it down. So you're telling
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me these guys essentially discovered a gas giant
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billions of miles away using a pencil and paper.
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A pencil, paper, and a lot of patience. Just
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by analyzing orbital speed wobbles, that requires
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an absolute, almost borderline arrogant level
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of faith in mathematics. It really is the ultimate
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triumph of the scientific method. So how did
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they actually prove it? Well, Le Verrier used
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the size and direction of those positional errors
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to calculate exactly where in the sky this hypothetical
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planet ought to be. He gave them coordinates.
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Yes. He mailed his math to an astronomer in Berlin
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named Johann Galli. And Galli. actually listened.
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He did. Galley received the letter, walked out
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to his telescope that very night, September 23,
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1846, pointed it at the exact spot Le Verrier
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suggested, and he found Neptune within about
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one degree of the prediction. Unbelievable. He
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looked through the eyepiece and essentially said,
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yep, the math checks out. It was a monumental
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moment. It proved to the world that the universe
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isn't just random chaos. It has rules. It follows
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predictable underlying rules. And if you understand
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the rules deeply enough, you can find things
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nobody has ever even seen. That is just brilliant.
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So math told us exactly where to look. But when
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Voyager 2 finally managed to actually visit Neptune
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in 1989... Ah, yeah. The physical reality was
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a bit of a shock. Totally threw all our neat
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predictions right out the window. Especially
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its weather. Oh, the weather on Neptune is terrifying.
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Voyager 2 clocked winds on Neptune at roughly
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2 ,000 kilometers per hour. 2 ,000? That is comfortably
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supersonic. Faster than the speed of sound in
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Neptune's own atmosphere, it is the most violent
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wind recorded anywhere in the solar system. Okay,
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let's stop and look at this logically because
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this breaks my brain. Let's do it. Weather on
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Earth... Our hurricanes, our jet streams, they
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are overwhelmingly driven by thermal energy from
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the sun. Correct. The sun heats the Earth unevenly,
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and that drives the weather. But Neptune is 30
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times further from the sun than Earth is. It
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is very far away. It gets a tiny, tiny fraction
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of a percent of the sunlight we do. So how does
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a freezing planet, practically sitting in the
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dark, generate supersonic winds? Where is all
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that energy coming from? It has to be coming
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from inside the planet itself. Inside. Yeah.
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Measurements actually show that Neptune radiates
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roughly two and a half times more heat out into
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space than it receives from the dim distant sun.
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Wait, so it's like a planetary furnace? A very
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slow leaking one. But yes, it has this mysterious
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internal heat source. What's causing it? It's
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likely primordial heat left over from the extreme
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friction and gravitational collapse of its original
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formation. So it's just been hot since it was
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born. Exactly. This deep internal heat slowly
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bubbles up toward the freezing surface, creating
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these massive temperature differentials. Wow.
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And in fluid dynamics, extreme temperature differences
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drive extreme circulation. That internal heat
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engine is what powers the supersonic winds. That
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makes sense. But here is the massive contradiction
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that drives planetary scientists crazy. I know
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exactly where you're going with this. Uranus
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doesn't do this. Nope. It is one of the deepest
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open mysteries about the ice giants. Because
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they are practically twins. Twins in size and
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composition, yes. Yet Uranus barely radiates
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any excess internal heat at all. It is incredibly
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cold all the way through its atmosphere. Wait,
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could that be connected to the giant impact we
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talked about earlier? The one that knocked Uranus
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on its side? You hit the nail on the head. That
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is actually one of the leading hypotheses. Yeah.
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Think about it. If a massive protoplanet slammed
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into Uranus, the sheer violence of that collision
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might have stirred up the interior so violently
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that it allowed all its primordial heat to just
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vent out into space billions of years ago. Oh
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wow, like cracking open an oven door. Precisely.
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While Neptune, having never suffered such a catastrophic
14:00
blow, managed to trap its formation heat under
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this thick, insulating blanket of atmosphere.
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Where it's still slowly leaking out today, causing
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2 ,000 kilometer an hour winds. Exactly. So one
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twin got cracked open and lost its heat and the
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other didn't. It's a tale of two planets. That
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is fascinating. And, you know, that internal
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churning inside Neptune, it doesn't just drive
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wild weather. Not at all. It creates these incredibly
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bizarre physical phenomena. Deep inside that
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mantle of supercritical ices we discussed. Yes.
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The weirdness goes all the way down. Let's talk
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about their magnetic fields, because honestly,
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they break every rule we thought we knew. They
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are wonderfully weird. So on Earth, our magnetic
14:39
field is fairly straightforward. Right. It acts
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kind of like a standard bar magnet. Right. It's
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generated by swirling molten iron in the planet's
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outer core. Because of that, the magnetic field
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is roughly aligned with our north -south spin
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axis, and it is centered right in the middle
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of the globe. But Uranus and Neptune completely
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ignore that blueprint. Completely. Their magnetic
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fields are tilted at steep, crazy angles. We're
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talking roughly 60 degrees for Uranus and 47
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degrees for Neptune. Which is already strange.
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But the weirdest part? The magnetic fields aren't
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even centered in the middle of the planet. No,
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they are offset wildly from the core. Why? How
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does that even happen? To understand why, we
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have to look back at that supercritical fluid
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soup we talked about earlier. The hot slush.
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Right. The magnetic fields of the ice giants
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aren't generated by a solid metallic core like
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Earth's. They are generated in that slushy, electrically
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conductive water ammonia mantle. Okay, I picture
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it like a washing machine with a totally unbalanced
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load. That is a great image. You have this conductive
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fluid sloshing and churning around. unevenly,
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way outside the center of the planet, spinning
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out this bizarre lopsided magnetic shield. That's
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spot on. That churning motion is called convection
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warmer fluid rising, cooler fluid sinking. Got
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it. And because it's happening in a relatively
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thin layer far above the core, the resulting
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magnetic field is wildly off -center. It's just
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so chaotic. Yeah. Speaking of things we can actually
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see, let's look at their color. beautiful planets
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they are both planets are a distinct blue But
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that isn't just, you know, an artistic choice
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in the textbook photos, is it? Right. There's
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hard chemistry behind that hue. It all comes
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down to the methane. Methane. Yeah. We mentioned
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methane is one of the deep supercritical ices,
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but it's also present as a gas in the upper atmospheres
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of both planets. Okay. And methane gas has a
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very specific optical property. It is highly
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efficient at absorbing red light. Ah. So the
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sunlight travels billions of miles out there,
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hits the atmosphere, the methane eats all the
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red wavelengths. Yeah. And only the blue light
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bounces back to our telescopes. That's exactly
16:47
it. Though if you look closely, there is a subtle
16:50
difference between the two. Yeah, Neptune is
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a deeper, richer azure blue, right? Yeah. While
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Uranus is a paler, almost muted cyan. Right.
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And since both planets have roughly the same
17:02
amount of methane, atmospheric scientists believe
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Uranus has an extra thick layer of photochemical
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haze. Photochemical haze. So basically planetary
17:11
smog. Exactly. Planetary smog that mutes the
17:14
deep blue into a paler pastel. That makes total
17:18
sense. Okay, I want to tackle the mystery that
17:21
genuinely sounds like a sci -fi movie pitch.
17:22
I know what you're going to say. Raining diamonds.
17:24
Yep. Is there actually a layer inside these planets
17:27
where diamonds fall like hail? The physics strongly
17:30
suggest it happens. Really? Yes. Deep within
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these planets, roughly 8 ,000 kilometers below
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the cloud tops, the pressure and temperature
17:37
reach a critical threshold. Okay. The pressure
17:40
down there is so immense that it physically crushes
17:43
the methane molecules. Wait, so methane is what,
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one carbon atom attached to four hydrogen atoms?
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That's right. The pressure actually snaps those
17:51
chemical bonds. It strips the hydrogen completely
17:54
away, leaving the carbon atoms floating free.
17:57
Wow. Now you have highly pressurized carbon in
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an incredibly hot, dense environment. Under those
18:04
specific conditions, the carbon atoms naturally
18:07
bond to one another, forming the most stable,
18:09
tightly packed crystal lattice they can. Which
18:12
is a diamond. Which is a diamond. And because
18:14
a solid diamond is denser than the fluid soup
18:16
around it, gravity takes over. Exactly. The diamonds
18:20
literally sink. or rain down toward the planetary
18:23
core. millions of carats of diamonds just sinking.
18:27
But come on, nobody has ever sent a probe down
18:29
there to catch one. How on earth can scientists
18:32
claim to know this is actually happening? You're
18:34
right to be skeptical, and this is where laboratory
18:35
physics comes in, which is so cool. Okay, tell
18:38
me. We can't go to Neptune, so scientists recreate
18:41
Neptune inside a laboratory. How do you recreate
18:44
Neptune in a lab? They take a type of plastic,
18:47
specifically PT plastic. It's the stuff standard
18:50
water bottles are made of. Like a Dasani bottle.
18:52
Exactly, because it has a chemical balance of
18:54
carbon, hydrogen, and oxygen that is very similar
18:57
to the ice giant interiors. Okay, so they have
19:00
the plastic. Then what? Then they blast that
19:04
plastic with one of the most powerful optical
19:07
lasers in the world. Blast it with a laser? Wait,
19:10
how does a laser simulate crushing gravity? The
19:13
laser hits the surface of the plastic so violently
19:16
that it instantly vaporizes the top layer. Oh,
19:19
wow. This creates an explosive shockwave that
19:21
travels backward through the rest of the material.
19:24
Let's see where this is going. Yeah. For a tiny
19:26
fraction of a second, that shockwave generates
19:28
the exact extreme pressure and temperature found
19:31
deep inside Neptune. And what happens? When they
19:33
analyze the plastic during that split second,
19:35
they literally observe microscopic diamonds forming.
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That is mind -blowing. They create a shockwave
19:42
in... a plastic bottle to prove that it's raining
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diamonds inside a plant we haven't visited in
19:47
40 years. It is a beautifully extrapolated model.
19:51
We use the laws of physics here on Earth to confidently
19:53
predict what happens in environments we can't
19:56
physically reach. The deeper we dive into these
19:58
mysteries, you know, the lopsided magnets, the
20:01
supersonic winds, the diamond rain, the more
20:04
I realize how heavily we rely on that one audacious
20:08
road trip Voyager 2 took. We owe so much to...
20:11
That little trobe. And we haven't even talked
20:13
about the weirdest things it found orbiting the
20:15
planets. The rings and the moons. Right. Because
20:17
for a long time, humanity assumed rings were
20:20
exclusively a Saturn phenomenon. It turns out
20:23
both Uranus and Neptune have complex ring systems
20:26
of their own. We actually found Uranus's rings
20:29
from Earth before Voyager even got there, right?
20:33
Yeah. Using something called stellar occultation.
20:35
Yes. In 1977, stellar occultation is a great
20:39
technique. Imagine watching a moth fly in front
20:41
of a distant streetlight. Okay. You can't actually
20:44
see the moth. It's too small and dark, but you
20:45
see the streetlight flicker. Oh, right. Astronomers
20:48
watched a distant star as Uranus was about to
20:51
pass in front of it. Before the main body of
20:53
the planet blocked the star, the starlight blinked
20:56
out several times in a very precise pattern.
20:58
Proving there were bands of solid material blocking
21:01
the light before the planet itself arrived. Exactly.
21:04
And Voyager 2 later captured stunning images
21:07
of them. But Neptune's rings are even stranger,
21:10
aren't they? Very strange. They are clumpy, uneven
21:12
arcs. Likely because the gravity of nearby small
21:15
moons is herding the ring dust into clumps. So
21:19
these aren't glorious sheets of reflective ice
21:20
like Saturn's. No, not at all. They are made
21:23
of dark, dusty, organic compounds. Quite possibly
21:28
the shattered remains of ancient moons that crashed
21:30
into each other. And just getting Voyager 2 out
21:32
there to see those rings was a miracle of orbital
21:35
mechanics. It really was a once in a lifetime
21:37
alignment. Because you couldn't just build a
21:39
rocket in the 1970s and shoot it straight at
21:42
Neptune. It would take too long and you'd run
21:44
completely out of fuel. Voyager 2 only achieved
21:46
its grand tour because of a rare planetary alignment
21:49
that happens exactly once. Every 175 years, Jupiter,
21:55
Saturn, Uranus, and Neptune were strung out in
21:57
a perfect arc. This allowed the spacecraft to
22:00
use a gravity assist or a slingshot maneuver
22:02
at every single stop. Basically stealing a tiny
22:06
microscopic fraction of Jupiter's orbital momentum
22:09
to whip the probe faster toward Saturn. Exactly.
22:12
And then doing it again at Saturn to reach Uranus
22:15
and so on. Without that 175 -year window, visiting
22:19
all four giants on a single mission simply would
22:23
not have been physically possible. We would have
22:24
missed our chance entirely. And thank God we
22:27
didn't, because the moons it found are absurd.
22:30
They are so weird. Let's look at Uranus's small
22:32
moon, Miranda. The surface looks like a jigsaw
22:36
puzzle put together by someone who was blindfolded.
22:38
That is the perfect way to describe it. I mean,
22:41
it has cliff faces many kilometers high, directly
22:44
next to smooth plains, directly next to grooved
22:47
ridges. Geologists suspect Miranda was literally
22:49
blown apart by a massive collision in its past.
22:52
Just shattered. Shattered. And then its own weak
22:55
gravity slowly pulled the jagged shards back
22:58
together into a messy, randomized sphere. But
23:01
as weird as Miranda is... Neptune's moon Triton
23:04
absolutely steals the show. Triton is fascinating.
23:08
First of all, Triton orbits Neptune backwards.
23:10
In a retrograde orbit, yes. Which tells us what?
23:12
It tells us immediately that Triton did not form
23:15
in orbit around Neptune. Right. When planets
23:18
and their native moons form from the same spinning
23:20
disk of material, they all revolve in the same
23:23
direction. Like spinning plates. Exactly. So
23:26
Triton orbiting backwards means it was a rogue
23:29
object from the Kuiper Belt. You know, the ring
23:32
of icy bodies beyond Neptune where Pluto lives.
23:35
So Triton was just minding its own business,
23:38
got too close to Neptune, and got captured by
23:40
its gravity. Snatched right out of the sky. But
23:43
getting captured must have heated it up massively
23:45
because Voyager 2 found active geysers on Triton,
23:49
didn't it? It did. On a moon where the surface
23:51
temperature is nearly absolute varro, Voyager
23:55
photographed dark plumes of material shooting
23:58
kilometers into the sky. How is that possible
24:00
if it's so cold? Sunlight barely warms the surface,
24:03
but it's just enough to turn frozen underground
24:06
nitrogen into gas. The gas pressure builds up
24:09
until it explosively ruptures the icy crust.
24:11
But Triton is on borrowed time, isn't it? It
24:14
is. A tragic end is coming. Because of that backward
24:17
orbit, tidal forces between Neptune and Triton
24:20
are slowly robbing the moon of its orbital energy.
24:24
Very, very slowly, Triton is spiraling inward.
24:28
And eventually it's going to hit something called
24:29
the Roche limit. The Roche limit is the invisible
24:32
boundary where a planet's gravitational pull
24:35
basically becomes fatal. Fatal for the moon.
24:38
Right. When Triton spirals close enough to Neptune,
24:41
the gravitational pull on the near side of the
24:43
moon will be significantly stronger than the
24:45
pull on the far side. It stretches it. That differential
24:48
stretches the moon. And eventually the structural
24:51
integrity of the rock and ice will just fail.
24:53
And Neptune's gravity will physically shred Triton
24:57
into trillions of pieces. Turning an entire captured
25:00
Kuiper belt object into the most spectacular
25:03
ring system in the solar system. That's going
25:05
to be a view, which brings us right back to our
25:08
original point. These aren't just lesser gas
25:10
giants. Not at all. They're highly complex, incredibly
25:13
dynamic worlds holding massive secrets about
25:16
planetary formation, violent impacts, and physics
25:19
that straight up break the rules. And the scientific
25:22
community fully recognizes this now. They do.
25:25
Yeah. Every decade, American planetary scientists
25:28
release a survey detailing their highest priorities.
25:32
Right, the decadal survey. In the most recent
25:34
one, a mission called the Uranus Orbiter and
25:36
Probe was ranked as the number one priority for
25:39
a new, large -scale flagship mission. Because
25:42
we have completely exhausted what we can squeeze
25:45
out of a single flyby from the 1980s. Exactly.
25:48
We need to go back. Obviously. Funding shifts
25:51
and rockets take years to build, but a real serious
25:54
case is finally building to go back. We need
25:57
to drop a probe into that atmosphere to measure
26:00
the noble gases. We need an orbiter to map that
26:03
off -center magnetic field over time. We simply
26:06
need more data. So to you listening, the next
26:08
time you look at a poster of the solar system,
26:10
don't let your eyes just gloss over those two
26:13
dim, neglected blue dots near the edge. They
26:15
deserve your attention. Think about the diamond
26:17
rain sinking toward the core. Think about the
26:19
supersonic winds in the freezing dark. Because
26:22
I want to leave you with one final thought. The
26:24
Kepler Space Telescope has spent years looking
26:27
at thousands of other stars, searching for exoplanets,
26:30
right? Yes, thousands of them. And do you know
26:32
what the most common type of planet in our galaxy
26:34
seems to be? I do. Planets roughly the size and
26:37
mass of Uranus and Neptune. Exactly. So if our
26:40
two ice giants are so wildly different from each
26:44
other in how they handle heat, weather, and magnetic
26:47
fields, What does that mean for the universe?
26:50
It's a profound question. Are Uranus and Neptune
26:52
the weird exceptions in the galaxy? Or are they
26:56
the standard rule? It forces us to ask how typical
26:59
our own solar system really is. And the only
27:02
way to find out is to go back into that cosmic
27:04
cupboard, wipe the dust off those forgotten artifacts,
27:06
and finally see what they really made of.