00:00Tell me the truth. You probably think that Earth's magnetic field is caused by a big ball of solid iron in the middle of the planet, right?
00:10Yep, I mean the inner core. But the problem here is that in the inner core, the temperatures are so high that the very magnetism of iron itself is changed.
00:22Once such a temperature, which is called the Curie point, is reached, atoms aren't able to align to a magnetic point anymore.
00:31So, in reality, Earth's magnetic field is created by the swirling outer core, and magnetism there is more than 50 times greater than it is on the surface.
00:42The liquid iron in the outer core conducts electricity perfectly, which helps it create electrical currents driving the magnetic field.
00:52Without it, our planet wouldn't be able to hold onto its atmosphere.
00:57As a result, we'd lose our main protection from extremely dangerous space radiation.
01:03But it wasn't the outer core that surprised us not so long ago.
01:07Scientists say Earth's inner core has likely stopped rotating relative to the mantle and the surface of the planet.
01:15Even more exciting, it could even go into reverse.
01:19But let's look into the details.
01:21Earth is formed of the crust, mantle, and outer and inner cores.
01:26The solid inner core is about 3,200 miles below the crust.
01:32It's separated from the semi-solid mantle by the liquid outer core.
01:37Yep, the one thanks to which we have the magnetic field.
01:41And since this outer core is liquid, it allows the inner core to rotate at a speed different from the speed of our planet's rotation.
01:50Earth's core has a radius of 2,200 miles and is almost as large as Mars.
01:57It mostly consists of iron and nickel and makes up around one-third of Earth's mass.
02:02The spin of the inner core is powered by the outer core.
02:07It turns out that the slowing of the core started in 2009.
02:12Since that time, seismic records, which had previously been changing continuously, have shown little difference.
02:20And it makes scientists conclude that the inner core's rotation has paused.
02:25But we're nowhere near the scenario of a disaster movie.
02:29Apparently, the inner core taking a temporary break is part of its 70-year long cycle.
02:35During this cycle, the core switches directions every 35 years or so.
02:40This might influence Earth's magnetic field and the length of the day, but some researchers are skeptical about it.
02:48And some scientists even go as far to say that the inner core isn't moving at all.
02:53Okay, but what would happen if Earth's core indeed stopped rotating?
02:58Well, if it was the solid inner core, the answer would be nothing dramatic.
03:04Even if it didn't just reverse the direction of its movement, like it's doing at the moment, but stopped altogether,
03:11it would just impact the speed of Earth's rotation.
03:14It'd slow down, making our days longer.
03:18Plus, with time, it could probably degrade our planet's magnetic field, and it would be bad news.
03:25But not as bad as they would be if the outer core stopped spinning.
03:29As you already know, without this layer's rotation, Earth would have to kiss its magnetic field goodbye.
03:36And that's how the downfall of the planet would begin.
03:39Things would start getting shaky.
03:41The tectonic plates would begin to slam into each other.
03:45You know, like when you're going by bus and the driver suddenly hits the brakes,
03:49and you end up flying into other unfortunate passengers?
03:52Yeah, like that.
03:54The sudden collision of tectonic plates would trigger destructive earthquakes along the plate boundaries all over the world.
04:01They would wipe buildings, bridges, and roads off the face of the Earth.
04:06Water systems, electricity, and phone lines would also be destroyed.
04:11But the worst would be yet to come.
04:13Without the protective magnetic field, cosmic radiation would start hitting the surface of our planet.
04:19These high-energy particles coming from the Sun would come in contact with oxygen and nitrogen in our atmosphere,
04:26effectively destroying our ozone layer.
04:29This would allow even more cosmic rays to reach the surface of Earth.
04:34The radiation would damage all kinds of electronic devices and disable power grids.
04:40And the consequences would be disastrous not only for people, but for all forms of life on Earth.
04:47The stationary core would make navigating the planet more difficult.
04:51People would have to start using trail maps again since compasses would become useless.
04:57It would also make it harder, if not impossible, for migratory animals to find their way.
05:03Birds would keep losing directions, and turtles would fail to find beaches where they used to lay eggs.
05:09Luckily, we don't need to worry about this kind of apocalyptic scenario.
05:14The planet's outer core is very unlikely to stop anytime soon, if ever.
05:19Now, do you want to find out something cool?
05:22Then listen to this.
05:23Our planet's inner core has a core of its own!
05:27Scientists have made this discovery just recently.
05:30They've learned that this core in the core could have developed around 500 million years ago
05:35as a result of some dramatic geological changes.
05:39What about other planets?
05:41Do they have the same cores as Earth?
05:44Let's look at Mars, one of our planet's closest neighbors.
05:47Its heart is the size of the Moon.
05:50It's also almost twice as dense.
05:53Scientists made this conclusion after they got some data about the first observed Marsquake and meteorite impact.
06:01Both these events were captured by NASA's InSight lander,
06:05which had been monitoring seismic activity on the Red Planet for four years.
06:10The researchers also estimated that Mars' core is probably made mostly of a liquid iron alloy
06:17with a smattering of hydrogen, oxygen, and carbon.
06:21One day, Mars probably had a nice rotating core that supported the planet's magnetic field.
06:27There could be warm oceans swarming with life.
06:30But then something must have happened, and on one terrible day, the Red Planet's core froze in place.
06:37It could have led to the weakening of Mars' once-strong magnetic field.
06:42Its atmosphere was taken away by powerful solar winds,
06:46hitting the planet at a speed of several hundred miles per hour,
06:50and the Red Planet turned into a lifeless, dry desert.
06:54Now, what about gas giants?
06:57Let's take the largest and the most massive planet in the solar system, Jupiter.
07:02It's twice as massive as all other planets of the solar system combined.
07:07Almost 1,300 Earths could fit into this huge thing.
07:11Jupiter also has the shortest day in the solar system.
07:15It lasts a mere 10 Earth hours.
07:19At the same time, the gas giant needs 12 Earth years to complete an orbit around the Sun.
07:25Jupiter most likely appeared at the same time when the rest of our solar system formed,
07:30about 4.5 billion years ago.
07:33Probably the coolest thing about this gas giant is that it has the same ingredients as a star.
07:40But unfortunately, or should I say luckily, it hasn't grown massive enough to ignite.
07:47Scientists don't know for sure what Jupiter's core looks like.
07:51According to most theories, the gas giant has a dense core made up of heavy elements.
07:57During its formation, it was probably a collection of debris, icy material,
08:02and other small objects like comets and asteroids zipping around.
08:06Thanks to their mutual gravity, these bits of matter clumped together,
08:11forming larger chunks which later turned into Jupiter's core.
08:15At one point, it became massive enough to start attracting hydrogen and helium.
08:20More and more gases accumulated around the core until what we today know as Jupiter appeared.
08:28There's also a possibility that Jupiter doesn't have a core at all,
08:32or it might have existed once, but since then, it's eroded away.
08:36Hopefully, we'll find out the answers to these questions soon enough,
08:40since Juno, NASA's space probe, is orbiting Jupiter,
08:45collecting data about its gravitational and magnetic fields.
08:49So, what about the gas giant's magnetic field, you may ask?
08:54Does it even exist?
08:56Oh, don't worry.
08:57Jupiter is surrounded by a ginormous magnetic field called the magnetosphere.
09:06That's it for today.
09:07So, hey, if you pacified your curiosity, then give the video a like and share it with your friends.
09:12Or if you want more, just click on these videos and stay on the Bright Side!
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