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What if you fell into Jupiter. Not the movie version. On December 7, 1995 the Galileo probe hit at 47.4 kilometers per second, lasted 58 minutes, and never found a floor.
0:00 The first second
0:42 The Only Thing That Tried
1:55 Radiation Before The Clouds
3:08 Two Point Five G And No Exit
4:20 The Ammonia Ice Deck
5:35 There Is No Floor
6:48 And It Gets Worse
8:00 Metallic Hydrogen
9:15 What Does Not Happen
10:25 The Fuzzy Core
Public-record thought experiment using NASA and peer-reviewed numbers. Interior depths and core pressures are model estimates. Not flight advice.
#Jupiter #WhatIf #NASA #GalileoProbe #JunoMission #GasGiant #SpaceScience #Astronomy
Visuals are original AI-generated stills. Narration is synthetic. Not medical, legal, or financial advice.
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0:00
On December 7th, 1995, at 22:04 UTC, a
0:04
337 kg NASA probe slammed into Jupiter
0:07
at 47.4 km per second. That is about
0:11
106,000 mi an hour. The carbon heat
0:14
shield reached 16,000° C
0:16
and shed 80 kg of itself in under 2
0:18
minutes. Peak deceleration was 228 g.
0:22
Then the radio lasted 58 minutes. You
0:24
would not last 58 seconds. And here is
0:27
the turn nobody puts on the poster.
0:29
The probe never hit a floor because
0:31
Jupiter does not have one.
0:33
The only thing that tried
0:36
Hughes Aircraft built that probe in El
0:38
Segundo. Galileo released it on July
0:40
13th, 1995, still about 80 million
0:44
kilometers from the planet, and it
0:46
coasted 5 months with no engine and no
0:48
second chance. You are not that machine.
0:51
You are a body in a suit, and the first
0:53
physical second is a wall of hydrogen
0:55
hitting you at 47 km per second. Entry
0:58
angle 8.4°.
1:00
Peak heating near 30 kW per square
1:02
centimeter. A 2.5 m parachute opened
1:05
after the shield did its job, and six
1:08
instruments started talking through 156
1:10
km of atmosphere. Mix molecular hydrogen
1:14
and helium, almost no water. Winds about
1:17
640 m per second. At roughly 180 km
1:21
below the entry ceiling, pressure sat at
1:23
22.7 atmospheres, and the transmitter
1:26
quit. Jupiter's equatorial radius at the
1:29
1 bar level is 71,492
1:33
km. The probe sampled about 0.22% of the
1:36
way to the center. That is the entire
1:39
human catalog of falling in. One dry
1:41
hotspot, one hour, one dead radio.
1:46
Radiation
1:47
Before the clouds
1:49
You do not start at the clouds, you
1:51
start in a magnetosphere. Jupiter's
1:53
field is about 20,000 times Earth's
1:55
dipole moment. On the sunward side, the
1:58
magnetopause sits 50 to 100 Jovian radii
2:01
out, 3 to 7 million kilometers of
2:03
charged real estate. Inside it,
2:05
electrons at tens of MeV and protons
2:08
past a GeV spiral on field lines.
2:11
Unshielded, a lethal dose arrives in
2:13
seconds. Your visor does not fog. Your
2:16
blood just stops being a working
2:18
instrument. Io orbits at about 422,000
2:22
kilometers and dumps roughly 1,000
2:24
kilograms of sulfur and oxygen into that
2:27
field every second. The Io plasma torus
2:30
is a donut of ionized volcano at 100,000
2:33
to a million Kelvin. You fall or rue it.
2:36
Your avionics arc. Galileo found an
2:38
intense belt about 50,000 kilometers
2:41
above the clouds. That is still vacuum.
2:43
You are dying in empty space that
2:45
happens to belong to Jupiter before the
2:47
first ammonia crystal ever touches
2:49
glass. Two, 0.5 G and no exit. Cloud top
2:54
gravity is 24.79
2:56
meters per second squared. Call it 2.5
2:59
G. A 70 kilogram body weighs about 175
3:02
kilograms at the one bar level and that
3:04
weight climbs as you sink toward more
3:06
mass. Escape velocity is 59.5 kilometers
3:10
per second, about 133,000 miles an hour.
3:13
Earth asks 11.2. You are not jumping
3:16
back. Equatorial spin is 12.6 kilometers
3:19
per second. A day is 9 hours 55 minutes.
3:22
Equatorial radius 71,492
3:25
kilometers. Polar radius 66,854.
3:28
The planet is 318 Earth masses and 1,321
3:32
Earth volumes. Mean density 1.33 grams
3:35
per cubic centimeter, about the density
3:37
of milk. That number is the first
3:39
physics insult. Something that large
3:41
should be rock. It is hydrogen with a
3:43
helium mixer, helium mass fraction about
3:46
0.23 and some of that helium is already
3:48
raining inward. Solar irradiance at
3:50
Jupiter is 50 watts per square meter
3:52
against Earth's 1,361.
3:55
The Sun is a dim coin. The planet makes
3:57
its own heat. The ammonia ice deck.
4:01
The one bar level is 165 Kelvin, minus
4:04
108 Celsius. Astronomers call it a
4:07
surface because they need a zero. 50 km
4:10
above it, the tropopause sits near 0.1
4:13
bar and 110 Kelvin. Scale height is 27
4:17
km. You hit ammonia ice first, white and
4:20
thin, then ammonium hydrosulfide, then
4:23
water ice if the column is wet. On
4:25
December 7th, 1995, it was not wet.
4:29
Galileo fell into a downdraft hot spot
4:32
and measured water below 3% of solar
4:34
abundance at 12 bars. Equatorial jets
4:37
run 150 m/s. The Great Red Spot is a
4:41
high-pressure storm at least 300 years
4:43
old, currently about 1.3 Earths across.
4:46
Rim winds near 120 m/s. You are a grain
4:50
in a shear layer, not a visitor. At 10
4:53
bars, about 90 km down, temperature is
4:56
already near 340 Kelvin. Room
4:58
temperature with no air. Volume mix
5:00
about 90% molecular hydrogen, 10%
5:03
helium. Methane around 3,000 parts per
5:06
million. Ammonia around 260. Mean
5:09
molecular weight 2.02. Your lungs fill
5:12
with a gas that has no oxygen. You
5:14
asphyxiate in a fog that looks like
5:16
weather and is actually the planet.
5:19
There is no floor.
5:21
This is still a logistics problem. You
5:23
packed for a landing. Boots, struts, a
5:26
place to stand. There is nothing to land
5:28
on. Hydrogen's critical point is 33
5:31
Kelvin and 13 bar. Jupiter blows past
5:34
that in the first few hundred
5:35
kilometers.
5:37
After that, gas and liquid are the same
5:39
substance, a supercritical fluid that
5:41
fills like a gas and packs like a
5:44
liquid.
5:45
Density at one bar is 0.16 kg per cubic
5:49
meter, thinner than Earth air. Then it
5:51
climbs without a phase change you can
5:53
point at. No splash, no crater, no, and
5:56
then you hit.
5:58
Juno entered orbit on July 4th, 2016,
6:01
after 2.8 billion kilometers. Its
6:03
gravity data showed the visible belts
6:05
and zones reach about 3,000 km down.
6:08
That is whether thicker than the drive
6:10
from Boston to Miami stood on end. You
6:13
fall through a storm with no basement.
6:15
The 10-bar level is paperwork. Below it,
6:18
the word atmosphere stops meaning
6:20
anything, and the word ocean has not
6:21
started yet. And it gets worse.
6:24
The part that actually matters is not
6:26
the cold. It is the squeeze. Galileo
6:29
died at 23 atmospheres, a scuba number.
6:32
A few thousand kilometers in, you are
6:34
looking at thousands of bars, then tens
6:36
of thousands. Temperature follows a dry
6:38
adiabat because heat can only leave by
6:41
convection. Around a million
6:43
atmospheres, molecular hydrogen breaks.
6:45
Electrons unbind. The fluid starts
6:48
conducting like a metal. Temperature
6:50
there is 5,000 to 10,000 Kelvin. You do
6:53
not crush like a soda can. You dissolve.
6:56
Carbon, nitrogen, the iron in your
6:59
blood, the calcium in your teeth, they
7:01
stop being anatomy and start being
7:03
impurities in a hydrogen solvent.
7:05
Terminal velocity is a joke because the
7:08
medium densifies under you faster than
7:10
you can fall. At some depth, your
7:13
density matches the fluid. You stop
7:15
sinking as a person and start mixing as
7:17
chemistry. That is not a landing. That
7:20
is a recipe. And the recipe does not
7:23
reverse. Metallic hydrogen.
7:25
That conducting ocean is the dynamo. It
7:28
is most of the interior. Currents in
7:30
spinning metallic hydrogen build the
7:32
magnetosphere that killed you on the way
7:34
in. Equatorial field about 4.3 Gauss
7:38
against Earth's 0.3. The magnetotail can
7:41
stretch towards Saturn's orbit up to
7:43
about 7,000 Jovian radii. Jupiter
7:46
radiates roughly 1.7 times the energy it
7:49
absorbs from the Sun. The extra is
7:51
leftover formation heat plus
7:53
Kelvin-Helmholtz contraction of about 1
7:55
mm of radius per year.
7:58
You are falling through a planet that is
7:59
still shrinking and still glowing from
8:01
the inside. There is no sunlight down
8:03
here. There is the infrared of
8:05
compressed hydrogen red, then yellow,
8:08
then white lighting the inside of a
8:10
visor that no longer has a face behind
8:12
it. Juno found the field is lopsided,
8:15
north not matching south, which means
8:17
the conducting layer is not a neat
8:19
sphere. You are inside a stirred metal
8:21
that does not keep a guest book. What
8:24
does not happen Earth does not get
8:26
pulled in tomorrow.
8:28
Jupiter sits at 778 million kilometers
8:30
from the Sun, 5.2 AU, orbital speed 13.1
8:35
kilometers per second, and it stays
8:37
there. Your house does not feel 2.5 G.
8:40
The Great Red Spot does not relocate to
8:43
Kansas. The 1995 probe did not open a
8:46
hole. Juno's 2016 insertion did not
8:50
crack a floor that was never there.
8:52
Comets do hit. Shoemaker-Levy 9 struck
8:55
in July 1994. About 21 fragments punched
8:59
dark scars that faded in months. That is
9:02
the public record analog of falling in
9:04
and the planet ate them and kept its
9:06
belts. You do not bounce. You do not
9:09
tunnel through to the other side. You do
9:11
not find a cavern of rock. You also do
9:13
not light a star. Core temperature is
9:15
about 20,000 Kelvin. The Sun's core is
9:18
15 million. Jupiter is short of fusion
9:20
by a factor of about a thousand in mass.
9:22
It is a planet. It remains a planet. The
9:25
solar system does not end because you
9:27
jumped. The fuzzy core Juno's gravity
9:29
harmonics killed the clean textbook. The
9:32
old picture was a compact rock-ice
9:34
kernel of maybe 10 Earth masses with a
9:37
sharp edge. The new picture is a dilute
9:39
core, heavy elements mixed into hydrogen
9:42
reaching perhaps 50 to 63% of the
9:45
radius. Central pressure around 40
9:47
million bars. Temperature around 20,000
9:51
Kelvin. There may be no surface even
9:53
there, just a gradient of rock-forming
9:55
stuff fading into metal. If anything of
9:58
you still had density left, you would
10:00
not stand on it. You would blend into
10:02
it. That is the last number.
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