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Space seems so big and far away. Distant galaxies, unheard-of planets, supermassive black holes thousands of light-years away. Then one day you find out all of it - the universe! - has striking similarities with the human brain! Their physical structure, their complexity. The universe has 100 billion galaxies, and your brain has about the same number of nerve cells! That and plenty more amazing space facts that'll stick in your mini-universe brain like glue!
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00:00A recent study suggests the universe is similar to your brain, only at a much, much larger scale.
00:08The brain's neural network contains about 86 billion neurons.
00:13The observable universe has at least 100 billion galaxies.
00:18Both galaxies and neurons have a similar structure.
00:22It's a complex web of nodes linking up long thread-like fibers.
00:26But in each of these systems, the fibers make up a mere 30% of the total mass,
00:32and the remaining 70% are either water in the brain or dark energy in the universe.
00:39The ways that galaxies and webs of neurons connect with one another are surprisingly similar.
00:46In both cases, the process follows the same physical principles.
00:51At the same time, some researchers claim the resemblance between the brain and the universe
00:56is only superficial.
00:58Your mind perceives tiny details and joins them.
01:01And then it comes up with a conclusion that has nothing in common with reality.
01:06Like, the brain is a mini-universe.
01:10In billions of years, the universe is likely to expand so much
01:14that we won't be able to see any stars in the sky.
01:18To turn Earth into a black hole, you'd have to squeeze it until it was the size of a marble.
01:25And if you wanted the sun to become a black hole,
01:27you'd have to compress it until it's no more than four miles across.
01:32A starburst galaxy is a galaxy that's forming tons of new stars at breakneck speed.
01:39It usually happens after two galaxies merge into one.
01:43While Earth has only one natural satellite,
01:46Jupiter is surrounded by at least 79 moons.
01:51In the universe, there are not only dwarf planets, but also dwarf galaxies.
01:57They have from 1,000 to a few billion stars.
02:00For comparison, the Milky Way galaxy is made up of 250 to 400 billion stars.
02:08A supermassive black hole 250 million light-years away from Earth
02:13hums the deepest sound ever detected from any object in the universe.
02:18It's one quadrillion, which is one with 15 zeros,
02:23times deeper than what the human ear can hear.
02:27Planet Kelt 9b is 670 light-years away from Earth.
02:32It's an ultra-hot Jupiter.
02:33Those are giant, scorching-hot planets with a mass similar to that of Jupiter.
02:39On Kelt 9b, the heat is so great on the day side of the planet,
02:45it tears molecules apart.
02:48Any liquid floating in outer space forms itself into a sphere.
02:53It also happens in low Earth orbit.
02:57Our home Milky Way galaxy is more than 105,000 light-years across.
03:02All the planets of the solar system would fit between Earth and the Moon with some space to spare.
03:10Black holes spaghettify things.
03:13It happens when something gets past the point of no return.
03:17Then the black hole's gravitational pull starts to stretch this object in one direction
03:22and squeeze in another.
03:25The first celestial body that astronomers identified as a spiral was the Whirlpool Galaxy.
03:32Its long arms are made of gas and stars,
03:35and everything is sprinkled with fine space dust.
03:40When you're on Earth, you can only see 5% of the universe.
03:46A star coming too close to a black hole can be torn apart by its gravitational force.
03:54WASP-12b is a giant planet 1,400 light-years away from Earth.
03:59It's made up mostly of gas.
04:01Unfortunately, the planet is doomed.
04:05It orbits too close to its parent star.
04:07In about 10 million years, WASP-12b will be swallowed by its greedy sun.
04:14Our Milky Way galaxy and the Andromeda galaxy, its closest neighbor,
04:19are going to meet in a bit less than 4 billion years.
04:23When they collide, they'll form one huge elliptical galaxy.
04:28One of Saturn's smaller moons, Enceladus, reflects almost 90% of the sun's light.
04:35It makes the moon one of the brightest objects in the solar system.
04:39But since it reflects sunlight instead of absorbing it,
04:43the temperatures on Enceladus' icy surface drop to negative 330 degrees Fahrenheit.
04:50The highest mountain in the solar system is Olympus Mons on Mars.
04:55It's three times as high as Mount Everest.
04:58If you were standing on top of Olympus Mons,
05:01its slopes would be hidden by the planet's curvature.
05:04In our solar system, Mercury and Venus are the only two planets without moons.
05:12Scientists who are planning to send droids to Mars
05:15want to load the machines with lots of heavy equipment.
05:31Pluto's largest moon is half the size of the dwarf planet itself.
05:35This makes Charon, that's the moon's name,
05:39the largest known satellite relative to its parent size.
05:43There are three golf balls on the moon.
05:46They were launched during the Apollo 14 mission.
05:51Mathematicians claim white holes might exist,
05:54even though scientists haven't found one yet.
05:57If you came across a white hole,
05:59you wouldn't be able to enter it from the outside.
06:02But you'd see light and matter escaping from within.
06:07On our planet, one full rotation takes one day.
06:11But the sun is so enormous,
06:13that it needs 25 to 35 Earth days to make one rotation.
06:19The moon is not a perfect sphere.
06:22It's shaped more like an egg,
06:24because of the Earth's gravity.
06:27Spacesuits protect astronauts from huge temperature differences during spacewalks,
06:31from negative 250 degrees Fahrenheit to positive 250 degrees Fahrenheit.
06:37A neutron star gets born after a supernova collapses.
06:42After birth, it rotates extremely fast,
06:45about 60 times per second.
06:47But this rate can sometimes grow up to 600 times per second.
06:53In 2007, astronomers started to receive
06:57ultra-bright and ultra-strong radio signals,
07:00named fast radio bursts.
07:03They were coming from somewhere billions of light-years away.
07:07When astronauts are in space,
07:09they often see random flashes of light.
07:12They occur when cosmic rays hit the optic nerve in the eye.
07:17If you traveled around Pluto's equator,
07:19it would be the same distance as walking from Rome to New York City.
07:24If you visited GJ-504b,
07:27a planet located a mere 57 light-years away from Earth,
07:32you'd see that the planet is glowing.
07:35It's because of the heat left after its formation.
07:39The planet's color is a dull magenta,
07:42like a dark cherry blossom.
07:44Jupiter has the shortest day of all the planets in the solar system.
07:48It lasts just 9 hours and 55 minutes.
07:52Because of its fast rotation,
07:54Jupiter isn't a perfect sphere.
07:56It's a bit flattened.
07:58Venus has more volcanoes than any other planet in the solar system.
08:02There are at least 1,600 of them on the planet's surface,
08:06but most of them are extinct.
08:10Mercury has wrinkles.
08:12When its iron core was cooling,
08:14the planet's crust contracted.
08:16It made the surface of the planet uneven.
08:21Nuclear pasta found inside neutron stars
08:24is believed to be the strongest substance in the universe.
08:28These noodles of neutrons
08:30can be 10 billion times stronger than steel.
08:34Some astronomers believe black holes
08:36might have no event horizon,
08:38aka the point of no return.
08:41Instead,
08:42there might be the apparent horizon.
08:45It can only trap stuff for some time.
08:47Later,
08:48matter or energy escapes,
08:50but in a different form.
08:53Each Apollo mission needed 15 spacesuits.
08:56Each member of the three-person main crew
08:59needed three suits.
09:00One was for training,
09:02the second,
09:03for flight.
09:04And,
09:04there was also a backup suit,
09:06in case something went wrong with the flight suit.
09:09And,
09:10each of the three members of the backup crew
09:12had two spacesuits,
09:13one for training,
09:14and one for flight.
09:17Scientists believe,
09:18Mercury might still have a partially molten core.
09:21It could explain
09:23why the planet has a magnetic field,
09:25even if it's just 1% as strong as Earth's.
09:29Dust storms on Mars
09:31are the most severe
09:32in the whole solar system.
09:34They can be raging for months on end.
09:37On planet Kepler-16b,
09:40which is 245 light-years away from Earth,
09:43not one,
09:44but two suns
09:45set over the horizon.
09:47The planet is as massive as our Saturn,
09:49but has a higher density.
09:52It takes 45 minutes to put on a spacesuit.
09:56After it's done,
09:57an astronaut needs another hour
09:59to adapt to new conditions.
10:02Earth-grazing fireballs
10:04are bright meteors
10:05that enter the Earth's atmosphere,
10:07but then leave it again.
10:09Triton,
10:10one of Neptune's moons,
10:11orbits the planet backward.
10:14It's the only big moon
10:15of any known planet to do so.
10:18Triton is also gradually
10:20getting closer to Neptune.
10:22Experts think that,
10:23eventually,
10:24the moon will be pulled apart
10:26by Neptune's gravity,
10:27and then,
10:28it'll form a ring around the gas giant.
10:31Dwarf planet Haumea,
10:33which is further from Earth than Neptune,
10:35is truly bizarre.
10:36It's orbiting in the Kuiper Belt,
10:38a donut-shaped ring
10:40of ice objects
10:41circling the Sun.
10:43Haumea has two moons,
10:45a weirdly elongated shape,
10:47and a day
10:48that lasts
10:49four Earth hours.
10:50But the coolest thing,
10:52the dwarf planet
10:53is surrounded
10:54by incredibly thin rings.
10:56They're likely the result
10:57of an ancient collision.
10:59It takes Neptune
11:00almost 165 Earth years
11:03to make one full orbit
11:05around the Sun.
11:06In other words,
11:07since the gas giant
11:08was discovered in 1846,
11:11it's only circled the Sun once.
11:14Now,
11:14as much as we love
11:15epic space battles
11:17with blasters
11:18cutting through the black void
11:19and causing cheerful booms,
11:21that's not exactly what happens
11:23when something explodes
11:24in the big black.
11:26Space is basically vacuum,
11:28meaning it has no oxygen.
11:29And oxygen is an essential part
11:31of any process of burning
11:33we have here on Earth.
11:34You might argue
11:35that stars can burn
11:37and explode into supernova,
11:38but that's not exactly true either.
11:41Stars don't rely on oxygen,
11:43so they're not burning.
11:44There are constant
11:45thermonuclear reactions
11:47going on inside them.
11:48Liquid oxygen,
11:49which is often on board spaceships,
11:51is very quick
11:52to burn out
11:53in the vacuum of outer space.
11:55As for the boom,
11:56oxygen plays a crucial role here too.
11:59Sound only travels
12:00thanks to molecules of air
12:02bumping into each other.
12:03Since there's no air in space,
12:05the whole scene
12:06would be pretty much
12:07absolutely silent.
12:09And that's not a bad thing either.
12:11Just imagine how deafening
12:12would the Sun be
12:13if the sound could travel in space.
12:16Despite what many sci-fi directors
12:18want us to believe,
12:19there's no dark side to the Moon.
12:22Our satellite is tidally locked with Earth,
12:25meaning it's always turned to us
12:27with one side,
12:28while the other always looks away.
12:30The Sun is much farther from us
12:32than the Moon,
12:33and we're both turning round and round,
12:35warming and lighting the side
12:37and that in turn.
12:38It means that once in every short while,
12:41the Moon is lit by the Sun
12:43from either side.
12:44It's just that we can't see it
12:46from where we are.
12:47While things appear weightless
12:49in outer space,
12:50there's actual gravity
12:51all over the place.
12:53It becomes weaker
12:54the further you get
12:55from a heavy object,
12:56like our planet,
12:57but it's still there.
12:59In fact,
12:59there's not a single place
13:01in the Universe
13:01that isn't affected by gravity
13:03of this or that cosmic object.
13:05Everything that has mass
13:07has gravity as well.
13:09Yes, even you and me.
13:11But space objects are so massive
13:13that they tug smaller things
13:15towards them.
13:15That's why the planets
13:17of the Solar System
13:18orbit around the Sun,
13:19and our whole Milky Way galaxy
13:21orbits around its own center.
13:23Scientists believe
13:24there's a supermassive black hole there,
13:27about 4 million times heavier
13:28than the Sun,
13:29which keeps all the stars
13:31and systems from flying apart.
13:33Our movie hero leaves the orbit of Mars
13:36on their trusty spaceship
13:37and heads on towards Jupiter.
13:39Their face is grim and determined,
13:41even though they know
13:42what threat awaits them ahead.
13:44The asteroid belt.
13:46They pitch and yaw,
13:48dodging the asteroid flying
13:49at enormous speeds
13:50toward the spacecraft,
13:52but one of them still hits it.
13:54No, just a scratch, thankfully.
13:56Finally, our hero leaves the danger zone
13:59and wipes the sweat from the brow
14:01with a shaking hand.
14:02Sounds familiar,
14:04but couldn't be further from the truth.
14:06Asteroids in the belt between Mars and Jupiter
14:08are so few and far between
14:10that if you ever travel through it,
14:12you might not even encounter one
14:14the whole way.
14:15There are about 1.5 million
14:18sizable space rocks flying there,
14:20give or take a half million.
14:22But let's not forget,
14:23space is a vast place.
14:25The distance between two asteroids
14:27of any significant size
14:28would be millions of miles.
14:30So a space chase with two ships
14:33weaving between floating rocks
14:34would be quite boring in there.
14:36Space is often depicted
14:38as a black, cold, and desolate place,
14:41especially when a movie astronaut
14:43leaves the safety of their spaceship.
14:45Everything about this description is okay,
14:48except for the cold part.
14:49It's only true if you find yourself
14:51in some really far corner of our galaxy
14:54that has no nearby stars.
14:56But if you're, for example,
14:58in the Earth's orbit
14:59and directly facing the sun,
15:01the temperature in the cosmic vacuum
15:03could reach a scorching 250 degrees.
15:06That's why spacesuits are white.
15:08This color reflects light
15:09better than any other.
15:10Still, the temperature at your back,
15:12which isn't exposed to the sun's rays,
15:15can be really freezing indeed.
15:17Heat doesn't spread equally through space,
15:19so if you're not turned towards a heat source,
15:22you get very, very cold.
15:24Speaking about the sun,
15:26it somehow always appears yellow in movies.
15:29The fact is,
15:30the color we see from Earth
15:31is an optical illusion
15:33created by our planet's atmosphere.
15:35Just as the blue sky during the day.
15:38The light from the sun spreads in the atmosphere
15:40and gets distorted,
15:42making colorful spectacles at dawn and dusk.
15:45In the vacuum of space,
15:46there's nothing to reflect the light,
15:48so the sun appears as it really is,
15:51white.
15:52That ball of glowing gas is that hot.
15:55There's a bright flash in the sky,
15:58followed by a tail of smoke,
15:59and a red-hot space rock crashes into the ground,
16:02leaving a huge, charred crater after impact.
16:06Well, although the smoky tail and the crater
16:08are partly true,
16:10meteorites don't really have a chance
16:12to become that hot while falling.
16:14Meteorite is an asteroid
16:16that somehow entered the Earth's atmosphere
16:18and survived the friction enough
16:20to fall on the surface.
16:22This happens pretty often,
16:23we just don't usually see those rocks,
16:25because they're normally quite small
16:27and fall into uninhabited areas.
16:30But even if one falls within a city,
16:32the crater would appear
16:33because of the sheer speed of the meteorite,
16:36not its heat.
16:37They do get much hotter because of friction,
16:39yet not so much as to burn everything
16:41on the ground on impact.
16:43As much as we want to believe
16:45in instant communication
16:46between spaceships and planets,
16:48it's not possible,
16:49at least not yet.
16:51Modern communication systems
16:53rely on radio signals
16:54that have a pretty slow speed
16:56compared to the vast expanses of space.
16:59It would take years
17:00for such a signal to travel
17:01even one light year,
17:03let alone hundreds and thousands.
17:05If you want to send a message
17:06to a galaxy far, far away,
17:09be prepared to wait a couple millennia
17:11and then a couple more
17:13to receive a reply.
17:14On that note,
17:16space is not as crowded and full of events
17:18as it's often shown on the silver screen.
17:21It's mostly a rather lonely place
17:23where planets, stars, and other objects
17:26are separated by billions of miles
17:28of nothingness.
17:30Even if you have a spaceship
17:31that can travel at the speed of light,
17:33most of the time,
17:34you'll only see black void
17:36full of stars and planets far away.
17:39The distances are enormous out there,
17:42even between the closest objects.
17:44For a better understanding,
17:46the moon,
17:46which you can see so well
17:48on a clear night,
17:49is about 239,000 miles away.
17:52It's like traveling around the Earth
17:54almost 10 times in a row.
17:56Warp drives
17:57that can distort space-time
17:59and get you to a distant corner
18:01of an alien galaxy
18:02in the blink of an eye,
18:03that's a staple of any space opera.
18:06Spaceships capable of such a feat
18:08are always shown as instantly accelerating
18:11from zero to faster than light.
18:13According to the law of physics,
18:15people on board should,
18:16well,
18:17at least be pushed into their seats hard.
18:20More strictly speaking,
18:21no one would be able to survive
18:23such an acceleration
18:24because it's too many Gs
18:26on a fragile human body.
18:28Until we find a way
18:29to reduce the effects of overload,
18:31we can't even start thinking
18:32of space warps.
18:34Water isn't the rarest
18:36and most precious resource
18:37in the universe.
18:38In fact,
18:39there's a humongous space cloud
18:41several million light-years away from us
18:43that consists entirely of water.
18:46Its reserves would be enough
18:47to fill all our oceans
18:49140 trillion times over.
18:52And many planets,
18:53some even in our solar system,
18:55seem to have liquid water on them.
18:57The most precious resource in space
18:59is life.
19:01And that requires a lot more stuff
19:02to appear than just liquid water.
19:05Astronauts are often shown
19:07working out on the ISS
19:08and sci-fi space stations.
19:10And that much is true.
19:12They do need physical activity.
19:14But the reason isn't
19:15that they need strong bodies
19:17to work in space.
19:18The gravity out there
19:19is much weaker,
19:20and astronauts don't use
19:21their muscles as much as on Earth.
19:23So when they come back
19:25to the surface,
19:26gravity hits them
19:27as a sledgehammer,
19:28and their bodies feel squishy.
19:30To alleviate those effects,
19:32they train every day.
19:34Although they say
19:36we can see millions of stars
19:37on a clear starry night,
19:39that number is much more modest,
19:41about 3,000.
19:43All the rest are other objects
19:44that are also luminous
19:46and mistaken for stars.
19:48Planets, distant galaxies,
19:50and even artificial satellites.
19:52They're simply being illuminated
19:54by real stars,
19:55just like the Moon,
19:56and become seen.
19:57But because they're that far away,
20:00we can't tell if they're stars or not.
20:02Still, you gotta admit,
20:04it's all still pretty cool.