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Alien Underworld Inside Uranus?! | Space's Deepest Secrets | Science Channel
Alien Underworld Inside Uranus?! | Space's Deepest Secrets | Science Channel
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คำบรรยาย (164)
0:01
The giant ice planet Neptune has a weird
0:04
moon.
0:06
Triton orbits in the opposite direction
0:08
to Neptune's rotation.
0:11
One explanation is that the planet
0:13
pulled Triton from the Kyper belt.
0:16
But what slowed down Triton enough to
0:19
allow Neptune to capture it traveling
0:21
the wrong way?
0:28
Astronomers believe that one of Pluto's
0:30
moons offers a clue.
0:34
Cheron is half the size of Pluto.
0:39
This closeness in size makes the pair
0:41
dance around each other as they orbit
0:43
the sun. [music]
0:46
Pluto is not much bigger like all the
0:48
other planets and moons. So instead of
0:50
being like a single large body with a
0:52
smaller one orbiting it, it's more
0:53
[music] like a dumbbell. And this
0:55
dumbbell orbits as one thing.
0:59
Astronomers call two orbiting bodies of
1:01
a similar [music] size a binary system.
1:06
The strange orbit of binaries could
1:09
unlock how Triton slows down enough for
1:12
Neptune to capture it, traveling the
1:14
wrong way.
1:20
When objects in the Kyper belt pick up a
1:23
partner, they completely change the way
1:26
they move through the cosmos.
1:33
Once they've caught each other,
1:36
they start revolving around their common
1:38
center of gravity.
1:44
This disrupts their trajectory as on
1:47
every [music] turn, one partner must
1:49
move backwards against their orbit.
1:55
Once every pirouette, they can slow down
1:58
so much that they become vulnerable to
2:01
capture.
2:05
Some astronomers believe that Triton
2:07
once had its own binary partner just
2:10
like Pluto has Cheron today.
2:14
They think that this missing binary is
2:16
the key that unlocks how Neptune
2:18
captures Triton.
2:20
The discovery that 10 to 15% of Kyper
2:23
belt objects are binary may solve the
2:25
Triton problem. If Triton itself was a
2:28
binary, it had a large companion when it
2:30
passed by Neptune. that could have put
2:33
the brakes on it and allowed it to orbit
2:35
Neptune.
2:41
Triton and its companion orbit each
2:43
other inside the Kyper belt.
2:46
Over time, Neptune's gravity gradually
2:49
pulls the pair away from the belt.
2:52
They fall towards the giant planet and
2:55
slingshot around it. Thanks to their
2:58
binary dance, there is a point when
3:00
Triton moves slowly enough
3:03
for Neptune to capture it.
3:06
This breaks the gravitational bond
3:08
between Triton and its partner and hurls
3:12
its companion across the solar system.
3:16
Triton is left alone, orbiting Neptune
3:19
the wrong way.
3:23
This companion was kind of a sacrificial
3:25
lamb that got kicked out into the depths
3:27
of space in order for Triton itself to
3:29
be captured into Neptune's orbit.
3:36
Triton's strange orbit is just one of
3:38
this weird moon's mysteries.
3:44
Voyager 2 photographs Triton up close in
3:48
1989.
3:52
The camera on board captures something
3:54
weird. On the surface of this strange
3:57
world
4:00
hidden in this grainy photograph is a
4:02
mysterious plume that rises from the
4:04
surface of Triton.
4:07
The plume is a geyser of frozen nitrogen
4:10
5 m high.
4:14
Winds in the moon's thin upper
4:15
atmosphere blow the vapor into trails
4:19
that are hundreds of miles long. When
4:21
Voyager flew past Triton, it saw the
4:24
unexpected. There were jets of gas
4:26
shooting out from the moon's surface. No
4:28
one expected that. It's out at the far
4:30
reaches of the solar system. We expected
4:32
to find a cold, dead moon. What the heck
4:36
is going on?
4:38
>> Why do geysers blast from the surface of
4:40
Triton? and what is the power source
4:43
that [music] drives them?
4:47
In 2019, investigators used the Gemini
4:51
South telescope in Chile to study
4:53
Triton's icy crust.
4:56
[music]
4:58
Researchers discovered that the ice on
5:00
the surface of Triton is a [music]
5:02
special cocktail of carbon monoxide and
5:05
frozen nitrogen.
5:06
>> In [music] some ways, you can think of
5:08
Triton as having a frozen atmosphere.
5:10
Our atmosphere on Earth is mostly
5:11
nitrogen. And that's true on Triton,
5:13
too. But the nitrogen is frozen into a
5:16
layer of ice.
5:18
That ice is actually transparent [music]
5:19
to light. So, sunlight can get through
5:22
that transparent ice and heat up little
5:24
[music] pockets in it.
5:27
Some types of ice transform directly
5:29
from a solid into gas when they heat up
5:32
inside an atmosphere that is super thin.
5:36
Astronomers believe [music] that this
5:38
volatility of Triton's ice unlocks the
5:41
mystery of its mega geysers.
5:47
At a point in Neptune's year, Triton's
5:49
north pole leans towards the sun.
5:54
This gives one hemisphere of the moon a
5:56
summer that lasts 41 Earth years.
6:00
The rays from the sun are weak,
6:04
but they can pass through Triton's
6:05
nitrogen ice.
6:09
Here, they hit a dark layer of dust,
6:12
which heats up by just a few degrees,
6:16
enough to turn the ice above into gas.
6:20
The pressure rises as the gas builds up
6:23
until it erupts as powerful geysers of
6:26
nitrogen.
6:34
Voyager 2 shows that ice giants contain
6:37
many secrets.
6:40
The data it beams back to Earth reveals
6:43
another mystery for astronomers to
6:45
solve.
6:47
The magnetometer on board the probe
6:49
detects that the magnetic field of
6:51
Uranus is super strange.
6:54
The field lines continually twist and
6:57
shift. The magnetic poles are offset
7:00
from the planet's axis of rotation by a
7:02
massive 60°.
7:06
Voyager 2 discovers later that the
7:08
magnetic field of Neptune is also
7:10
irregular and misaligned.
7:13
When you think about the magnetic field
7:15
of a planet, sometimes you get something
7:17
very simple like the Earth. It's almost
7:19
as if there's a giant bar magnet going
7:21
right through the core of our planet
7:22
with a very clear north pole and south
7:24
pole. With the ice giants, something
7:26
altogether different is going on. The
7:28
magnetic fields are chaotic. The
7:30
magnetic field lines twist and turn like
7:33
a bag of writhing snakes. And the south
7:35
pole of the planet is actually along the
7:38
equator.
7:40
>> Why are the magnetic fields of the ice
7:42
giants twisted?
7:45
Can a strange material deep inside
7:47
Uranus unlock the [music] mystery.
