Movies have made us believe some wild things about space! For starters, in reality, you can’t just explode in space, like they show in movies—there’s no air to cause that kind of blast. And those super-loud spaceship battles? They’d actually be silent because sound can’t travel in the vacuum of space. Then there’s the idea that asteroid fields are like an obstacle course; in reality, they’re so spread out that you’d probably never bump into anything. And what about quicksand-like black holes sucking everything in? They’re more like cosmic whirlpools that only pull in things very close to them. Oh, and if you tried to plant a flag on the Moon like in the movies, it wouldn’t flutter—there’s no wind to make it wave!
00:00Many sci-fi movies can make you believe that everything happening in space is accompanied by some kind of sound effect, which is a totally false misconception.
00:11In space, no one will hear you scream. There's no air in space. It's an almost perfect vacuum.
00:17And the sound waves don't travel through a vacuum.
00:21They can't reach your eardrums and make them vibrate, sending signals to your brain.
00:25But it's a good thing, especially for astronauts on spacewalks.
00:30If not for the quietness of space, they would be constantly overwhelmed by the noise of solar storms.
00:39Huge space explosions sure look super impressive.
00:43Whether they're scientifically possible or not is another question.
00:47Blasts on our home planet look the way they do because of air and gravity.
00:52You see, the air functions as an oxidizer, and the outward pressure makes everything fly into the air and then collapse back to the ground.
01:02But this process is very different in space, and it looks even cooler.
01:07If a blast occurred in space, there would still be some fire despite the lack of air because some kinds of fuels can act as oxidizers.
01:14But it wouldn't be the fire you're imagining now.
01:18This cosmic fire would look like an expanding ball of light.
01:22It would be a seemingly never-ending process due to microgravity and the lack of air resistance.
01:29Nearby spaceships would be in grave danger since the shrapnel would fly outward until something eventually stops it.
01:36All comets have beautiful long tails.
01:42Huh?
01:43It's nothing but a popular misconception.
01:45In reality, comets are very difficult space bodies to spot.
01:50They usually spend large amounts of time far away from stars.
01:54There, in the darkness of space, they remain rather inactive and completely frozen.
02:00Comets only get tails once they come close to a star.
02:03That's when they start warming up.
02:06This process makes them form some kind of a cloudy atmosphere, which is called a coma, and a distinctive tail.
02:14The tail always points away from the star that influences the comet.
02:19It happens because the tail gets blown in the opposite direction by solar radiation and solar winds.
02:25That's why the tail can often be in front of the comet, not trailing after it.
02:30The inner and outer planets of the solar system are separated by the asteroid belt, a ring of asteroids and other debris and space objects orbiting around the sun.
02:41While creating movies about space, filmmakers make sure to somehow use this region.
02:46Usually, they show the asteroid belt as an extremely crowded place with dense clouds of huge rocks you have to skillfully maneuver to get through to the other side.
02:56In reality, if you looked outside your spaceship while flying through this region of space, it would feel as if you were looking at the sky from Earth.
03:04All because of the ginormous distances in space.
03:09If you decided to cross the asteroid belt, there would be very little chance of a collision with a space object.
03:15Asteroids there are really spaced out and very far from one another.
03:19Black holes are giant, scary, cosmic vacuum cleaners, they say.
03:27But in reality, black holes are more like fly traps.
03:30They don't look for things to munch on.
03:32Instead, they sit out there quite passively.
03:35Only when a star or any other object comes too close does a black hole spring into action.
03:41Even so, only those space bodies that cross a certain border get ripped apart.
03:45In fact, black holes aren't any different from any other celestial body since their pull is directly proportional to their mass.
03:53They can't swallow anything bigger than what their size allows.
03:58Even if our sun was somehow replaced with a black hole as massive as itself,
04:03nothing would change for Earth or any other planet in the solar system.
04:07Gravitationally speaking, of course.
04:09Space battles in movies often involve using lasers.
04:17But if you were to see such a fight from up close, you would probably be disappointed.
04:22The thing is, it would be like nothing in movies.
04:25A laser beam is a concentrated burst of energy, and it could indeed be used for many purposes during a fight.
04:31But a real-life laser beam would be totally invisible in space since there wouldn't be any particles around to scatter the light
04:39and make the beam bright red or green or any other color.
04:46A human would be torn into pieces if they got into open space without a spacesuit.
04:51Well, contrary to popular belief, taking off a spacesuit during a spacewalk wouldn't be as dramatic as it's often pictured in movies.
04:59A person would just lose consciousness due to a lack of oxygen after 15 seconds of being in outer space without protection.
05:08But that's if this person breathed out as much air as possible.
05:11Otherwise, this oxygen would damage their lungs from the inside, making them rupture.
05:17After that, without the protection of the spacesuit, the pressure inside their body would drop.
05:23This would cause even more serious trouble.
05:25And even though this person definitely wouldn't burst, they wouldn't want to stay outside for too long.
05:34People often believe that in space, you experience zero gravity.
05:39Hence, the weightlessness astronauts feel on the International Space Station.
05:43But that's not exactly true.
05:45Gravity is one of the most important forces that exist in the universe.
05:49Thanks to it, the moon orbits Earth and the sun doesn't float away, out of our home Milky Way galaxy.
05:57Astronauts on the ISS do experience the effects of gravity.
06:01But that's not full-fledged.
06:02It's microgravity.
06:04The gravity on the space station is only 10% weaker than the gravity on Earth's surface.
06:10But astronauts are constantly in freefall.
06:12The spacecraft, people inside, and all the objects aboard keep falling forward, not down, but around our planet, following a specific orbit.
06:23And since they're all falling together, the crew and the stuff inside seem to be floating.
06:29That's why astronauts can move things as heavy as hundreds of pounds with their fingertips.
06:34And even though microgravity is often called zero gravity, they are very different things.
06:40A light year must mean time, right?
06:46Not really.
06:47Light years actually measure distance.
06:50NASA's definition of a light year goes like this.
06:53The total distance that a beam of light moving in a straight line travels in a year.
06:58And since light moves at a speed of 186,000 miles per second, a light year equals almost 6 trillion miles.
07:10It may seem as if the sun is always on fire.
07:14At least that's what it looks like in pictures and in movies.
07:17But in reality, our star is a giant ball of gas.
07:21Nuclear reactions happening in its core at all times make the sun burn.
07:26Every second, hundreds of millions of tons of hydrogen are converted into almost as much helium.
07:32During this process, huge amounts of energy are released as gamma rays.
07:38Then these rays turn into light.
07:40In other words, the sun does emit blinding light and incredible heat, but it's not actually on fire because no oxygen is involved in the process.
07:49The speed of light is believed to be the ultimate barrier for people when it comes to space travel.
07:57And it's often thought to be impassable.
08:00There are many theories about what it might be like to reach that speed, but none of the equations account for going above it.
08:07And still, we know that at least one thing in the universe is faster than the speed of light.
08:12The rate of its expansion.
08:13Yep, the universe is expanding faster than the speed of light, baffling astronomers and casual sky watchers alike.
08:22Or at least we can say so in terms of the speed of different objects, like faraway galaxies relative to each other.
08:30At the moment, it's not something scientists understand well.
08:33The rate of the expansion of the universe is proportional to how far something is, too.
08:39The farther it is from us, the faster it's moving away.
08:42But even though we don't get the mechanics of it yet, we've got our proof, even though it's theoretical so far,
08:49that some particles might be able to travel faster than the speed of light.
08:54Some scientists think there could be more things out there in space that could challenge this speed barrier.
09:00All we need to do is find them.
09:02That's it for today.
09:05So hey, if you pacified your curiosity, then give the video a like and share it with your friends.
09:10Or if you want more, just click on these videos and stay on the bright side.
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