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The Godfather of the Universe! | How the Universe Works | Science Channel - Video học tiếng Anh
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The Godfather of the Universe! | How the Universe Works | Science Channel
The Godfather of the Universe! | How the Universe Works | Science Channel
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0:02
It's an old familiar story.
0:06
A bunch of planets orbit a yellow star
0:09
in a quiet suburb of the Milky Way
0:11
galaxy.
0:14
But it's not the whole story.
0:18
>> Over the past decade, our vision of our
0:21
solar system has been completely
0:23
revamped.
0:25
>> Think of the solar system as an
0:27
old-fashioned mafia crime family.
0:30
The sun is the don. His quarreling
0:33
children, the planets.
0:35
Their story, like any good mob movie, is
0:38
an epic tale of empire [music] building,
0:40
sibling rivalry,
0:42
greed, and ultra-violence.
0:46
>> The origin of the solar system was
0:47
chaotic and violent. Planets colliding,
0:50
planets even changing places.
0:54
>> Now, a shift in our understanding
0:57
reveals a tale [music] of tangled
0:59
alliances between family members.
1:03
>> Just think about how much our view of
1:05
the solar system has changed. The
1:07
planets used to be so far away from each
1:09
other, and of course they had nothing to
1:11
do with each other, and now the history
1:13
is all about the interaction.
1:14
>> So, the idea that everything is just its
1:17
own world and doesn't interact is
1:20
completely wrong.
1:21
>> We like to think of astronomy as looking
1:23
up, looking outward, away from
1:25
ourselves. But the more we do that, the
1:27
more we realize how connected we are to
1:30
everything out there.
1:32
>> You probably have some material in your
1:34
body from pretty much every world that
1:35
ever existed in the solar system.
1:39
>> Like any good mobster movie, our story
1:41
starts with the humble rise of the
1:43
godfather.
1:45
In this tale, that's the birth of the
1:47
sun.
1:49
But exactly how that happens is a
1:52
mystery.
1:54
>> When we're trying to figure out how the
1:55
solar system began, you know, we don't
1:57
have a time machine. So, what can we use
2:00
to find out about how it formed?
2:05
>> The solar system has the answer.
2:08
It's own time machines.
2:10
Meteorites.
2:16
>> Meteorites are pieces of the solar
2:17
system from the distant past and they've
2:19
remained unchanged since then. So,
2:21
they're like little time capsules.
2:27
>> They're like fossils from before our
2:29
solar system even formed.
2:31
>> By studying them, we can really study
2:33
what was happening, what was going on in
2:35
the very early days of our own solar
2:37
system.
2:40
>> 2020
2:42
Scientists study ancient material
2:44
trapped inside a meteorite found in
2:47
Murchison, Australia.
2:50
>> The Murchison meteorite contains tiny
2:52
crystals called pre-solar grains that
2:55
predate our sun.
3:01
>> And trapped within them is evidence of
3:04
the history of the formation of our
3:05
solar system.
3:08
>> The pre-solar grains are made up of
3:09
elements like silicon that form inside
3:13
giant stars.
3:19
When these stars die, they blow out huge
3:21
clouds of gas and grains of dust.
3:25
>> The term pre-solar grain doesn't sound
3:27
very romantic, but actually, we might
3:30
call those stardust because these
3:31
materials are things that were made in
3:33
stars that no longer exist.
3:37
>> The Murchison meteorite contains grains
3:39
from at least 46 different stars.
3:44
>> What the Murchison meteorite tells us is
3:46
that the material that came together
3:48
that formed our solar system
3:50
had its origination in dozens of
3:53
different stars.
3:55
>> These stars died and blew out all of
3:58
these materials and then created this
4:00
huge cloud of gas and dust called a
4:03
nebula.
4:05
>> The sources of the material in that
4:06
cloud could come from one of a number of
4:08
places. The material from lots of stars
4:11
atmospheres could be mixed in there.
4:14
>> In the mix were the ingredients to build
4:17
the solar system.
4:19
But we don't know what triggered the gas
4:21
and dust to form the sun.
4:25
A 2020 study may have the answer.
4:30
>> One of the coolest things we've
4:31
discovered in the last couple decades
4:33
about the Milky Way [music] is there's a
4:34
giant stream of stars that's stretching
4:36
across virtually the whole sky.
4:39
>> [snorts]
4:42
>> These stars were not born in the galaxy.
4:44
They're not from here.
4:48
>> If not from our galaxy,
4:50
then from where?
4:52
>> We think these stars actually came from
4:56
the Sagittarius dwarf galaxy which
4:58
orbits the Milky Way.
5:02
>> Over 5 [music] billion years ago, the
5:04
Sagittarius dwarf galaxy wanders too
5:07
close to the Milky Way.
5:11
Our galaxy's powerful gravity drags
5:13
Sagittarius towards it.
5:16
The galaxies collide.
5:19
>> As this is happening, the Milky Way is
5:21
tearing Sagittarius apart, ripping stars
5:24
out of it.
5:26
>> This is truly intergalactic cosmological
5:30
drama at play.
5:34
>> This collision shakes up the Milky Way.
5:37
>> When a body passes through the disc of
5:41
our galaxy, it's going to set off
5:43
ripples and that's going to compress the
5:44
gas clouds and that's going to create
5:47
star formation.
5:48
>> The Sagittarius dwarf smashing into the
5:51
Milky Way is like dropping a boulder
5:54
into a pond.
6:01
It sets out ripples of density, and it
6:04
disturbs everything in the galaxy, but
6:07
it doesn't disturb everything equally.
6:09
It causes some clumps of dust and gas to
6:13
start accumulating together.
6:19
>> The disruption in one galactic zip code
6:22
leads to new activity in others across
6:24
the Milky Way.
6:27
The ripples trigger gas and dust [music]
6:29
left over from the dying stars to split
6:31
into clumps,
6:33
sparking a frenzy of star formation.
6:37
>> Look, if you were an observer, suddenly
6:40
out of these little clumps of gas come
6:43
bright ignition sparks, all at once.
6:50
If you were to stand there long enough
6:52
watching this stellar nursery, it might
6:55
look kind of like a field at night with
6:56
fireflies blinking on.
7:00
>> Perhaps the sun formed in this
7:02
starburst.
7:04
>> The passage of the Sagittarius dwarf
7:07
through our galaxy correlates in time to
7:10
the formation and birth of our sun, so
7:12
maybe our solar system came about as a
7:16
result of the Sagittarius dwarf passing
7:19
through our galaxy over 5 billion years
7:21
ago.
7:22
>> Of course, we don't know for sure if
7:24
this is what triggered the formation of
7:26
our sun, but the timing does fit.
7:31
>> 4.6 billion years ago,
7:35
part of the cloud seeded [music] with
7:36
material from dying stars grows denser
7:40
until it gets so massive it collapses.
7:46
>> As the gas cloud collapses, it gets
7:49
hotter and hotter and spins faster and
7:52
faster forming a dense core at its
7:55
center.
7:57
The core is the protostar that will
7:59
later become our sun.
8:02
>> The protostar drags in more and more gas
8:05
and dust creating a region of material
8:09
spinning around it called the
8:10
protoplanetary disk.
8:14
>> As the sun builds up more mass, it's
8:17
getting compressed gravitationally. And
8:19
so the core is getting hotter and hotter
8:21
and hotter. The densities are
8:22
increasing.
8:26
>> The new dawn, the head of our solar
8:28
mobster family, immediately reveals a
8:31
ferocious nature.
8:33
Blasting out supercharged jets of
8:36
radiation.
8:38
>> The early sun was not the calm glowing
8:42
orb that we see in our sky today. It was
8:45
far more chaotic.
8:49
It's sort of like in its toddler phase.
8:51
It was acting up all the time.
8:56
>> It has all of this energy that pushes
8:58
material off of the surface and launches
9:00
it into what we call the solar wind.
9:04
>> The blizzard of particles races out at
9:07
over a million miles an hour.
9:10
It smashes into the protoplanetary disk
9:13
and blows the gas away.
9:17
At the same time, the sun's core heats
9:19
up to 18 million degrees Fahrenheit
9:23
triggering the fusion of hydrogen into
9:26
helium.
9:27
>> And that releases a tremendous amount of
9:29
energy that eventually works its way
9:31
back to the surface of the star and
9:33
comes out as light.
9:37
>> Finally, the sun becomes the
9:39
recognizable Sun that we see in our sky
9:41
today.
9:44
>> The Sun
9:45
is now the Godfather, pulling the
9:47
strings of the solar system.
9:51
The young Don's rise to the top triggers
9:53
a power struggle with its willful
9:55
children, the planets.
9:57
It's a brutal fight for survival.
