- 2 hours ago
If many earthquakes happen on the planet, there's a lot going on under the surface. If we talk about Earth, it's the movements of tectonic plates. Most earthquakes happen along their edges. But what about other planets? Let's find out! Today, you're about to figure out what lies under the surface of each planet in the Solar System! Get into your spaceship equipped with the largest drill you can only imagine – and off you go!
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00:01Well, looky here! You're about to figure out what lies under the surface of each planet in the solar system.
00:07Get into your spaceship, equipped with the largest drill you can only imagine, and off you go!
00:13You start with Mercury. It's the closest planet to the Sun.
00:16At first sight, the place looks similar to our good old Moon.
00:20But after landing, you understand it's an illusion.
00:24All around your spaceship, there are craters left by meteorites.
00:28The planet's surface is littered with huge steep hills.
00:31Some of them are 2 miles high and stretch for hundreds of miles.
00:35You start drilling and immediately understand it's going to be tough.
00:39Mercury is the second densest planet in the solar system, topped only by Earth.
00:44The planet's outer shell is 250 miles of solid crust and rocky mantle.
00:50After getting through it, you see Mercury's metallic core.
00:53It takes up almost 85% of the planet's volume, and contains more iron than any other planet we know
01:00about.
01:01You don't need to drill anymore. The outer core is liquid.
01:05But once you reach the solid inner core, you have to switch that drill on again.
01:09The next planet you're going to explore is Venus.
01:13It's the hottest planet in the solar system.
01:15The average temperatures there are high enough to melt lead.
01:18The pressure on the planet is 90 times greater than that on Earth.
01:22Your spacecraft is traveling through thick clouds of sulfuric acid.
01:27Venus's surface is reddish-brown and extremely dry.
01:31You land in the middle of a flat, smooth plane.
01:34Planes like this cover two-thirds of the planet's surface.
01:37Well, you get down to work.
01:39The drill starts moving through the crust.
01:41It consists mostly of basalt and is almost 12 miles wide.
01:46The next layer is a molten rocky mantle.
01:49After some time, you get the feeling it'll never end.
01:52No wonder. It's 1,200 miles thick.
01:56Finally, you arrive at the planet's metallic iron core.
01:59It's huge. Twice wider than the mantle.
02:02Jupiter.
02:03Almost 1,300 Earths could fit into this huge thing.
02:07It's also alarmingly hot, about 43,000 degrees at the core.
02:12But you can't land on Jupiter because it doesn't have any solid surface.
02:17The planet is a gas giant, the key word here being gas.
02:21Your drill is also of no use, at least at first.
02:25While descending, you watch thick brown, yellow, red, and white clouds passing by.
02:30Thanks to them, the planet looks colorful and beautifully striped.
02:35You keep going deeper toward the center of the planet.
02:38Its atmosphere is made up of hydrogen and helium gas.
02:42Soon, you see the hydrogen become liquid under immense atmospheric pressure.
02:46And closer to the core, this liquid turns into a mixture of metallic hydrogen and helium.
02:52You read something that looks like a core.
02:55But even with the help of your equipment,
02:57you can't figure out whether it's a molten ball of liquid or a solid rock 14 to 18 times the
03:03mass of Earth.
03:05Maybe, one day, astronomers will help you answer this question.
03:09The next planet turns out to be exceptionally windy, like me.
03:13The winds on Saturn travel at more than 1,100 miles per hour at the equator.
03:19From above, it looks as if the gas giant has a solid yellowish-brown surface.
03:24You get through several different layers of clouds.
03:27And suddenly, you realize you can't land your spacecraft here as well.
03:31Saturn is the least dense planet in the solar system.
03:35It has only one-eighth the average Earth's density.
03:38If you found a pool of water large enough to fit the ringed planet, the gas giant would float.
03:44If you kept going down, you'd probably have found Saturn's core.
03:48It's likely to be rocky, with hydrogen and helium surrounding it.
03:53Ah, you're approaching the ice giant Uranus.
03:56Which means there's going to be some surface to land on.
03:59Or not.
04:00The planet isn't solid.
04:02You fly through the upper atmosphere and sink into the liquid icy center.
04:06The ice, which makes up 80% of the planet's mass, is actually a hot, dense fluid.
04:12It consists of water, ammonia ice, and methane.
04:16This part of the planet is sometimes called a water-ammonia ocean.
04:20This ice surrounds a solid, rocky core.
04:23That's where you can finally use your drill.
04:25The core's small, half the Earth's mass.
04:28Compared to other planets, it's also rather cool.
04:31A mere 9,000 degrees.
04:34You're reaching the farthest point of your journey, Neptune.
04:37It's four times the size of Earth, but 17 times as heavy.
04:42The bluish surface you see, when coming closer, is a layer of permanent clouds and swirling gas.
04:47Below this surface, there's a large mantle, liquid and red-hot.
04:53The mantle is rich in methane, ammonia, and water, and equals 15 Earth's masses.
04:59At last, you have something to drill.
05:02The planet's core is solid.
05:04It consists mostly of iron and other metals.
05:06Keep drilling until you're at a depth of 4,500 miles.
05:11Astronomers are almost sure that's where you'll find a diamond layer.
05:14That's right, it rains diamond crystals there.
05:18Well, time to go back home.
05:20People have drilled pretty deep holes here.
05:22But they were never deep enough to even get through the crust.
05:26After the drills traveled one-third of the way, the temperature reached 360 degrees,
05:31and the equipment couldn't operate any longer.
05:34But your drill is much stronger than that.
05:37That's why you easily move through the crust.
05:39It takes up only 1% of Earth's volume and is broken into tectonic plates.
05:44They let heat escape from the Earth's interior.
05:47You reach the mantle.
05:49This layer is about 1,800 miles thick and makes nearly 84% of the planet's volume.
05:55It consists of silicate rocks rich in iron and magnesium.
05:59Well, you don't need to drill anymore.
06:01The 1,500-mile-thick outer core is liquid.
06:04It consists of iron and nickel, but the pressure isn't high enough for it to be solid.
06:10You pass through the boundary between the outer and inner core.
06:13It's quite a challenge.
06:15The temperature there is 10,800 degrees, as hot as on the Sun's surface.
06:20And the pressure is 3.3 million times the atmospheric pressure at sea level.
06:25The inner core is a solid ball made of iron and nickel.
06:29Its radius is 760 miles.
06:32It makes 20% of the Earth's radius and 80% of the moon's.
06:37Scientists know what's going on under the crust of the planets that are millions and billions of miles away from
06:42us.
06:43And they don't even need to go there, drill through their surface, and peek inside.
06:47They combine information about the planet's density, magnetic field, mountain ranges, heat, and seismic activity to make their smart assumptions.
06:56For example, Earth's magnetic field shields us and the atmosphere from solar flares and solar winds.
07:03Scientists believe that it exists thanks to a hot iron core inside the planet.
07:08It rotates and generates invisible protection, like an enormous scorching hot dynamo.
07:14And this magnetic field is way stronger than that on Mars.
07:18It probably means that something happened to the red planet's core.
07:22Maybe it cooled down and kind of switched off.
07:25Or maybe there wasn't any magnetic field to begin with.
07:29There are loads of active volcanoes on Earth's surface.
07:33That's how scientists can conclude there must be a relatively thin crust.
07:37And the mantle must be made of liquid magma.
07:40But Martian volcanoes aren't active anymore.
07:43There could have been a hot liquid mantle under the planet's crust once.
07:47But after the volcanoes formed, something went wrong.
07:51The interior probably cooled down.
07:53Or the crust somehow became thicker.
07:56Whatever it was, it successfully stopped magma from getting to the surface.
08:01And then there's also seismic activity.
08:04If many Earth or Mars or Venus quakes happen on the planet, there's a lot going on under the surface.
08:10If we talk about Earth, it's the movements of tectonic plates.
08:14Most earthquakes happen along their edges.
08:18If there's little seismic activity on the planet, it might have no plate tectonics.
08:22Then its interior is calm.
08:25Researchers also pay attention to how long it takes a seismic wave to go through a planet or how it
08:31echoes inside.
08:32It can help to get more information about the density of the crust, what the mantle's made of, and so
08:38on.
08:39But scientists have to be extremely careful with the causes of these earthquakes.
08:43Sometimes they can occur after meteorites hit the planet.
08:47And it has no connection with the processes going on under the surface.
08:51Of course, these last two methods will only work with rock planets.
08:56Mainly because gas giants have neither volcanoes nor seismic activity.
09:00Boy, all this talk about thin crust and thick crust is making me hungry.
09:06Hey, you up for some pizza?
09:08Is that Earth you can see at a distance?
09:10Right.
09:11Just look at it, floating in space, hanging out with its planet buddies.
09:15You spot orange-red Mars and Jupiter with its asteroid belt.
09:20Even tiny Pluto is there.
09:24All these planets keep their distance from each other, moving along in their own orbits.
09:29They're not very social, you see.
09:30But that's a good thing.
09:32It would cause nothing but trouble if they started to bump into each other.
09:37But even though there are others, Earth is the only planet we know that has life.
09:42And we've even figured out why.
09:45It's because it was lucky enough to appear in the best spot in our solar system.
09:50In the Goldilocks zone.
09:53Scientists say the key ingredient for life is water.
09:57But, well, there's water on Mercury.
10:00This planet has deposits of water ice at its south and north poles.
10:05But only because those places never see the light.
10:08Everywhere else, water simply evaporates from the surface of the planet.
10:12But Mercury is way too close to the Sun.
10:16Pluto has some water too.
10:19Astronomers even think the dwarf planet might be up to 30% water.
10:24But it's frozen.
10:26Unlike Mercury, Pluto's too far away from the Sun.
10:30Which is why all its water is in the form of ice.
10:34But Earth hovers in a perfect spot called the habitable zone.
10:38It has the right temperature for the water to remain liquid.
10:42And for all forms of life to flourish.
10:45But what if Earth was the only planet in the solar system?
10:49No Mars, no Jupiter, no Mercury, no Venus.
10:52Things might have turned out a little different than what we're used to.
10:56Remember that massive asteroid that hit the Earth around 66 million years ago?
11:01Well, without Jupiter and its asteroid belt,
11:04our planet would be constantly hit by meteorites and asteroids.
11:09And some of them would be just as big as the one that caused all that sorrow to the dinosaurs.
11:15These rocky fellas would be roaming around in space with no one and nothing to stop them.
11:21And if Earth was the only planet out there, it would also be their only target.
11:27But that's not all.
11:29Look at all this huge space Earth would have all to itself.
11:33It means our planet would have an opportunity to travel a bit.
11:37It could even choose to leave the Goldilocks zone.
11:40But then, would life on the planet still be the same?
11:44So let's say Earth started drifting away from the Sun.
11:48Then, it'd soon get too cold on the planet.
11:51Picture a place where the Sun doesn't shine anymore.
11:55Dark, cold, covered in ice and snow all year round.
12:00That would be our Earth if it traveled further from the Sun.
12:03If this happened, our cities would start to look very different.
12:08Right now, Earth is full of life.
12:11Come to any park, and you'll see green trees and grass everywhere.
12:15There will be people walking, sitting on the benches, enjoying the Sun.
12:19You'll definitely spot someone playing soccer or Frisbee.
12:22On the park's lawns, there will be people resting on their blankets, soaking up the Sun.
12:28A few people will be reading their books, looking relaxed and happy.
12:33Back in space, you see Earth again.
12:35The planet is still in its favorite spot.
12:38That's why life is so beautiful down there.
12:40But wait, is it moving?
12:44Our planet is definitely further from the Sun now.
12:47Has it changed things for Earth?
12:49It actually looks a bit bluer now.
12:52Down there, famous Golden California is not so golden anymore.
12:57It's gloomy and dark, much like all other places on Earth.
13:02New York is covered in ice.
13:04Even in the hottest places, the temperatures are now below freezing,
13:09including tropical destinations like the Bahamas.
13:12After a while, liquid water turns into ice.
13:16The oceans now look like giant skating rinks.
13:19Except there's no one to skate there,
13:22since the planet has become way too cold to support life.
13:26Okay, then what if, instead of drifting further away from the Sun,
13:31Earth moved closer, with people still aboard?
13:35Whoa, the temperatures here are crazy!
13:38Too hot to handle!
13:39The climate would be getting hotter and hotter.
13:42Natural disasters would start to occur more often.
13:45Hurricanes and floods would be a common thing on Earth now.
13:49And pretty soon, the planet would get too hot for people to handle.
13:53Particles from the Sun would become a serious threat.
13:56The atmosphere would be struggling to protect Earth from solar radiation.
14:01But this shield would be growing weaker.
14:04Liquid water would be nowhere to be found anymore.
14:07Maybe only in underground deposits.
14:09Earth would look a bit like Mars, all rocky and barren.
14:13The Mississippi River would dry up and leave behind a huge canyon.
14:18All the oceans would be gone, too.
14:21At the moment, the Mariana Trench is the deepest known place on Earth.
14:25It's incredibly hard to reach its bottom because of the immense water pressure there.
14:30But without water, trips to the deepest spot on Earth would be possible.
14:34It would help people uncover some more of Earth's secrets.
14:38If people still lived on the dry and scorching hot planet, that is.
14:41In other words, if someone was to explore Earth after the planet had moved closer to the Sun,
14:48everything would be completely different.
14:51But what if Earth didn't move at all and everything remained the same?
14:55The only difference?
14:56There would be no other planets around us.
14:59It would change the way people explore space.
15:02Sure, there would still be navigation, communication, and weather satellites.
15:09But there wouldn't be any other space objects close enough for people to send missions there.
15:15This would affect the future, too.
15:17If people had no desire or opportunity to go to space, they would invest in their home planet.
15:23They would build sky cities instead of looking for other planets to colonize.
15:28These days, if you get a state-of-the-art telescope, you'll see distant stars and other planets.
15:34The better the telescope, the more detail there is for you to see.
15:39But with no other planets out there, the picture of space wouldn't be so exciting.
15:44Stars would still be visible, and you might even spot a meteorite or two.
15:48And you'd definitely see the Moon.
15:50But that's about it.
15:53Space agencies would mostly be focused on keeping Earth secure.
15:57Mainly because asteroids would become frequent visitors.
16:00To protect the planet, scientists would have to figure out ways to get rid of them.
16:05Like a massive laser beam.
16:08When turned on, it could go all the way to the Moon and even further.
16:13Instead of building rockets to explore space,
16:16SpaceX and NASA would be in the asteroid-clearing business.
16:21People wouldn't even think of trying to contact other civilizations.
16:24If there were no planets similar to Earth, they would consider it a wasted effort.
16:30This means no radio signals being constantly sent out to space.
16:34A curious fact.
16:36In February of 2008, the Beatles song Across the Universe was beamed into deep space.
16:43It was done to celebrate both the song's 40th anniversary and NASA's 50th anniversary.
16:50In the 70s, people also sent a radio signal out into space.
16:54It contained some basic information about humans and the solar system.
16:59But it was more a feat of strength for technology
17:02than an attempt to contact any alien buddies we might have.
17:07With no planets around, the world of sci-fi would change too.
17:11There would be no more movies about deep space exploration.
17:15No massive spaceships and rockets would appear on the big screen.
17:19And since there would be no expeditions to other planets,
17:22no rovers would be sent to space to look for signs of life and explore new worlds.
17:28Like what the rovers on Mars are doing right now.
17:32People would concentrate more on their own planet.
17:35For example, they would begin to explore its insides.
17:38New technologies would allow us to dig much, much deeper.
17:42All the way through Earth's crust and further.
17:45And doesn't a trip to the planet's core sound exciting?
17:49Instead of astronauts, there would be explorers of the deep underground.
17:54New drilling technologies would be invented to make the digging process more effective.
17:59There would be new types of vehicles.
18:01They would be created to drill and protect explorers from the enormous underground pressure.
18:06While exploring the world under the planet's surface,
18:10people would likely find absolutely new life forms.
18:14Those would be mysterious creatures that evolved to survive in the dark,
18:18in extreme temperatures, and with barely any food.
18:22It certainly helped people understand more about their home planet.
18:27Magma oceans, supersonic winds, scorching hot days,
18:31and instead of rain, a bunch of rocks falling on your head.
18:35Just another one of those days, huh?
18:38Astronomers recently discovered a new super planet out there.
18:42K2-414b is an exoplanet that's around 200 light-years away
18:48and in serious need of a new name.
18:51An exoplanet is just a fancy way of saying that a planet orbits its own star in another solar system.
18:57The Earth orbits the Sun, so this planet has its own orbit party going on.
19:02So what makes K2, bunch of numbers, so scary?
19:06Picture our beautiful little blue planet Earth.
19:09Now imagine that all the volcanoes in the world suddenly erupted at the same time
19:14and lava covered the oceans and seas.
19:17Fiery hurricanes, thousands of times faster than normal,
19:21blow all over the place, 24-7.
19:24And it starts raining rocks every now and again.
19:27Rocks! Like on your head!
19:29Thankfully, not in your head.
19:31This scary planet came into our lives about two years ago.
19:35Scientists are still studying it.
19:38So, what's a typical day life?
19:40For starters, you can forget about breathing.
19:43Oxygen decided to take a pass on this planet.
19:45You'd have to get used to sodium, silicon monoxide, and silicon dioxide.
19:50Which is, as you guessed, not great.
19:53And that's just scratching the surface.
19:55Who knows what other chemicals are lying around?
19:58And yes, magma oceans.
20:00The planet's surface is covered in molten magma as far as the eye can see.
20:05This lava planet orbits really close to its star,
20:08which is why the surface is like a fireplace.
20:10The closest planets to our sun are Mercury and Venus.
20:14But this planet's even closer.
20:16And what's even more weird is that half the planet is in constant daytime.
20:21The other half, night.
20:23It's tidal-locked, just like our moon is.
20:26No matter how long you stare at it, you'll never see the other side.
20:30That's why the all-day, everyday scorching, fiery side is so hot and overflowing with magma oceans,
20:37while the other side's in a constant state of deep freeze.
20:41If the magma doesn't burn you, you've still got big problems.
20:44And please, don't look up.
20:46It's raining rocks.
20:47On Earth, water turns to steam, rises up, becomes clouds, cools, and falls as rain.
20:53Over there, on planet Fireball, it's exactly the same, except for it's rocks, people.
21:00The planet's so hot, it vaporizes rocks.
21:03Oh, and don't forget the supersonic winds with speeds up to 3,000 miles per hour.
21:08Imagine your hat getting blown off your head at five times faster than an airplane.
21:13The strongest win on Earth was the tropical cyclone Olivia that hit Australia.
21:17It was blowing at 250 miles per hour.
21:20Now imagine 12 times that.
21:23On the sunny side of the planet, you're looking at a roasting 5,000 degrees.
21:28The hottest it ever got on Earth's surface was in California, 135 degrees.
21:33It's pretty common for it to get near that temperature in the Sahara Desert,
21:37but that kind of heat's not exactly enough to make rocks evaporate.
21:42If you grew up near a desert, you already know how dry and hot it always is.
21:47But did you know that deserts can reach freezing temperatures?
21:50A desert, by definition, is a large area with little or no rainfall.
21:56That means no water vapor to keep the temperatures from going insane.
22:00In the daytime, the sun heats up the desert like an oven.
22:03But when the sun sets, the heat packs up and heads home, and it can get really cold.
22:09Some deserts have even reached minus 40 degrees at night.
22:13But wait, shouldn't deserts have snow if it's that cold?
22:17Well, some deserts have had a bit of snow here and there.
22:20But because there's no water vapor, there can't be that much snow.
22:24Just dry, freezing, sandy Sahara nights.
22:28Now, the Sahara Desert's actually not the largest desert on Earth.
22:32It's Antarctica.
22:34Five million square miles of icy dryness, almost no people, and a whole bunch of cute penguins.
22:40Penguins technically live in a desert.
22:44Back to the fireball planet, this time, the night side.
22:48Never-ending darkness and extreme cold, about minus 330 degrees.
22:53Add in some supersonic winds?
22:55Earth's coldest?
22:57Minus 130 degrees at a research center in Antarctica.
23:01So, how does this jalapeno-pepper-exo planet stack up against some of our neighbors?
23:07Well, Mars isn't exactly livable, either.
23:10It's the red planet, so you'd think it'd be hot most of the time.
23:13But it's usually freezing.
23:15Well, way below freezing.
23:18And if you're planning a weekend getaway to Mars, you can leave the umbrella at home.
23:23Nah, it doesn't rain rocks, and it actually hasn't rained there for millions of years.
23:28At least Mars has days and nights, and it's like Earth in other ways.
23:32Mars' equator is steamy hot, and it gets pretty cold at the north and south poles, just like Earth.
23:38And it's like Earth.
23:39Scientists even discovered old bits of carbon dioxide snow there.
23:43The entire planet is actually covered in carbon dioxide, with a splash of nitrogen here and there.
23:51Scientists even reported intense snowstorms on Mars.
23:54But because it's mostly carbon dioxide, it's not your typical snowstorm.
23:59It's more like a dry ice storm.
24:01That's the stuff they use in fog machines.
24:05Mars isn't the only place where climates are going cuckoo.
24:09Jupiter's famous for its gigantic storms.
24:12Not like the ones we know on Earth.
24:14I'm talking about storms that last for centuries.
24:16The great red spot on Jupiter is actually a 400-year-old storm,
24:21and you could fit four whole Earths inside of it.
24:24So it's been around for a while, but it's nowhere near as intense as the storms on K2.
24:31Venus also has intense rain, but it's not made of rocks.
24:35It sort of works.
24:36It rains sulfuric acid.
24:38That stuff can give you severe skin burns and rip nasty holes through your umbrella.
24:43Venus's atmosphere is filled with carbon dioxide,
24:47which acts like a net to trap in the Sun's radiation, and it's insanely hot.
24:52No magma oceans, though.
24:56Mercury is the closest planet to the Sun and doesn't even have an atmosphere.
25:00That means no storms, clouds, rain, wind, whatever.
25:05Mercury is kind of like a desert here on Earth.
25:07No water vapor and no rainfall.
25:10That means temperatures shoot up during the day and drop like crazy at night.
25:14The K2 exoplanets, like the most extreme parts of all of our solar system,
25:19all rolled into one scary planet.
25:22But we're not headed there anytime soon.
25:25We haven't even been to Mars yet.
25:27That's all way off in the future, and 200 light years is a really long travel time.
25:33If we're going to move anywhere anytime soon,
25:35we'll probably want to set up camp on the Moon.
25:38No magma oceans, no warp speed winds, nice temperatures.
25:43So, where would we even start?
25:45Well, the main issue is that drones and remote-control robots are getting more and more advanced.
25:51It's way cheaper to send them over to map out the Moon for us while we're safe here on Earth.
25:58And if we ever want to begin space exploration for real,
26:02we'd need a proper space base.
26:04And what better place than our little shiny Moon?
26:07So, why do we even study those far-off planets?
26:11What's the point?
26:12Well, planets are like people.
26:14They're all different ages and live in all different places.
26:17The more of them we study, the more we can understand why there's life,
26:21aka us, on Earth and not on any other planet so far.
26:27When we see crazy new planets, we get crazy new ideas,
26:31which can turn into awesome inventions that make our lives easier.
26:34Even just going into space gives us new ideas.
26:38Scratch-proof lenses, some firefighting equipment,
26:42water filtration systems, wireless headsets,
26:45invisible braces, that tiny vacuum you've used to clean those crumbs in from between your couch cushions.
26:50They were all invented to help astronauts work better in space.
26:54And now they make our lives better every day.
26:57Maybe we'll figure out a new energy source someday,
27:00thanks to a far-off planet or star.
27:03Or we might discover a new compound that will make our buildings stronger or more energy efficient.