- 2 hours ago
Are you ready for a round of fresh facts about space? There are so many myths about space out there that people keep believing. Like what really happens if you fall into a black hole? And can we really save Earth if an asteroid is flying toward us? Here are the most incredible facts about space and the solar system to finally forget about those common myths everybody believes!
Category
🎈
FunTranscript
00:01They say, somewhere out there, there's a pen that can work in zero gravity, at extreme temperatures, and even underwater.
00:08They say this pen can write on almost any surface, or if you turn it upside down, or when your
00:14surroundings are heated up to 570 degrees Fahrenheit.
00:17They say NASA spent millions, or probably billions of dollars, and almost a decade to develop such a pen.
00:24The problem with ballpoint pens in space is that they don't work in the conditions of weightlessness.
00:30The ink can't flow to the ball normally, since gravity doesn't affect it.
00:34Instead, pressure is created in the ink reservoir, and pens start leaking.
00:39Some time ago, NASA used pencils, but wooden pencils were considered to be a fire hazard in most spaceships.
00:45All because, at that time, the atmosphere inside them was 100% oxygen.
00:51The need for a superpen was obvious.
00:53But whatever the rumors claim, NASA did not create such a pen, spending a fortune on the research.
01:00Its development was sponsored by Paul C. Fisher of the Fisher Pen Company, based in Chicago.
01:05He spent over $1 million and almost 10 years to make a pressurized ink cartridge.
01:11It was supposed to allow space pens to function in zero gravity and other extreme conditions.
01:16Eventually, they got a pen that could write at a temperature of minus 30 to 250 degrees Fahrenheit, which is
01:23really impressive, isn't it?
01:25The pen was patented in 1966.
01:28And, one year later, after conducting several thorough tests, NASA started to provide Apollo astronauts with such pens.
01:35Interestingly, the rumors about NASA spending an insane amount of money on the development of space pens have been circulating
01:42for decades.
01:43They have been debunked many times, but they appear again and again.
01:48Many sci-fi movies can make you believe that everything happening in space is accompanied by some kind of a
01:54sound effect, which is a totally false misconception.
01:58In space, no one will hear you scream.
02:00You know why?
02:01There's no air in space.
02:03It's an almost perfect vacuum.
02:05And sound waves don't travel through a vacuum.
02:08They can't reach your eardrums and make them vibrate, sending signals to your brain.
02:12But it's a good thing, especially for astronauts on spacewalks.
02:16If not for the quietness of space, they would be constantly overwhelmed by the noise of solar storms.
02:22Here's another one.
02:24All comets have beautiful long tails.
02:26It's nothing but a popular misconception.
02:29In reality, comets are very difficult space bodies to spot.
02:33They usually spend large amounts of time far away from stars.
02:37There, in the darkness of space, they remain rather inactive and completely frozen.
02:43Comets only get tails once they come close to a star.
02:46That's when they start warming up.
02:48This process makes them form some kind of a cloudy atmosphere, which is called a coma, and a distinctive tail.
02:55The tail always points away from the star that influences the comet.
02:59It happens because the tail gets blown in the opposite direction by solar radiation and solar winds.
03:05That's why the tail can often be in front of the comet, not trailing after it.
03:10Now, let's look at a light year.
03:13This very notion makes us believe we speak about time here.
03:16But in reality, light years measure distance.
03:20NASA's definition of a light year goes like this.
03:23The total distance that a beam of light moving in a straight line travels in a year.
03:28And since light moves at a speed of 186,000 miles per second, a light year equals almost 6 trillion
03:36miles.
03:37Hey, do the math!
03:39Now, people often believe that in space, you experience zero gravity.
03:44Hence the weightlessness astronauts feel on the International Space Station.
03:48But that's not exactly true.
03:50Gravity is one of the most important forces that exist in the universe.
03:54Thanks to it, the moon can orbit Earth, and the sun doesn't float away from our home Milky Way galaxy.
04:00But the astronauts on the ISS experience not full-fledged, but microgravity, which means very small gravity.
04:08The gravity on the space station is only 10% weaker than the gravity on Earth's surface.
04:13But astronauts are constantly in freefall.
04:16The spacecraft, the people inside, and all the objects aboard keep falling forward, not down, but around our planet, following
04:24a specific orbit.
04:25And since they're all falling together, the crew and the stuff inside seem to be floating.
04:31That's why astronauts can move things as heavy as hundreds of pounds with their fingertips.
04:36And even though microgravity is often called zero gravity, they're very different things.
04:41Now, it may seem as if the sun is always on fire.
04:45At least, that's what it looks like in pictures.
04:47But in reality, our star is a giant ball of gas.
04:52Hey, I can relate.
04:53Nuclear reactions happening in its core at all times makes the sun burn.
04:58Every second, hundreds of millions of tons of hydrogen are converted into almost as much helium.
05:04During this process, huge amounts of energy are released as gamma rays.
05:09Then, these rays turn into light.
05:11In other words, the sun does emit blinding light and incredible heat.
05:15But it's not actually on fire, because no oxygen is involved in the process.
05:21A human can explode if they get into open space without a spacesuit.
05:25Well, contrary to popular belief, taking off a spacesuit during a spacewalk won't be as dramatic as it's often pictured
05:33in movies.
05:33A person will lose consciousness due to a lack of oxygen after 15 seconds of being in outer space without
05:40protection.
05:41Before it happens, the person should breathe out as much air as possible.
05:45Otherwise, this oxygen will damage their lungs from the inside.
05:49Then, without the protection of the spacesuit, which is like a mini spaceship, the pressure inside their body will drop.
05:56This will cause even more serious troubles.
05:58And even though this person definitely won't burst, they won't want to stay outside for too long.
06:04Black holes are giant, scary, cosmic vacuum cleaners, they say.
06:08But in reality, black holes are more like fly traps.
06:12They don't look for things to munch on.
06:14Instead, they sit out there quite passively.
06:17Only when a star comes too close does a black hole spring into action.
06:21Even so, only those space objects that cross a certain border get ripped apart.
06:26If the sun were suddenly replaced with a black hole, Earth's orbit wouldn't change.
06:32At the same time, Earth's temperature would be different.
06:34There would be no solar wind, and no magnetic storms created by the sun would affect our planet.
06:40And let's say the black hole that replaced the sun had the same mass as our star.
06:45Then, according to the law of physics, Earth would have to come very close to get pulled into this black
06:50hole.
06:51Now, the dark side of the moon myth was debunked more than 50 years ago.
06:55And still, not everyone knows that this dark side is simply part of the Earth's natural satellite that faces away
07:02from our planet.
07:03By no means is it darker than any other region of the moon.
07:07And sunlight falls equally on all sides of the satellite.
07:10It only seems dark because we never see this side of the moon from Earth.
07:15All because of the phenomenon known as tidal locking.
07:18Over billions of years, ooh, let me say that again, billions of years,
07:23the gravitational connection between our planet and its natural satellite has changed their orbits.
07:29The speed at which they move has also become different.
07:31And since Earth is way bigger than the moon, the satellite's rotation was gradually slowing down.
07:38Until at one point, it reached the point of balance.
07:40And now, it takes the moon the same time to make a full rotation around its axis and to fully
07:46orbit around Earth.
07:48Now, you might have heard people referring to Venus as Earth's twin.
07:52It's true that both these planets are of almost the same size.
07:56They have similar mass and composition.
07:59The surface gravity on Venus is 91% of that on Earth.
08:03So, if your weight was 100 pounds on our planet, on Venus, you'd weigh 91 pounds.
08:08And still, calling these planets twins is a step too far.
08:12The atmosphere on Venus is 100 times thicker than that on Earth.
08:16Plus, its surface temperatures are insanely high, up to 850 degrees Fahrenheit.
08:22That's hot enough to melt lead or burn up your pizza.
08:25Venus has no water oceans or any life forms.
08:29It also rotates backward compared to all other planets of the solar system, including Earth.
08:34By the way, another myth claims that Mercury is the hottest planet in the solar system.
08:39After all, it's the closest planet to the Sun, but Venus is actually hotter.
08:45Asteroids strike Earth much more often than people tend to believe.
08:48But most of these collisions aren't history-changing extinction events.
08:52Most of them go completely unnoticed.
08:55Most asteroids that approach our planet are qualified as small, near-Earth objects.
09:00They usually burn up in Earth's atmosphere before they even have a chance to wipe out life off the surface
09:06of the planet.
09:07Not that they're big enough to do that.
09:09And still, around 40 to 80 tons of space debris fall on Earth every year.
09:14Most of this debris is tiny asteroids, also called bolides.
09:19They're usually no larger than 65 feet in diameter.
09:22Um, that's small?
09:24Yeah, says so right here.
09:25Okay.
09:27Traveling at about 17,000 miles per hour, 250 miles above the Earth,
09:33astronauts watch 16 sunrises and sunsets every day while floating around in a box with a handful of people they
09:40depend on for survival.
09:43Whether humans should set off to other worlds beyond Earth or not,
09:47one of the most compelling drawbacks is this.
09:49Our bodies don't like it.
09:52Few people know this better than the NASA astronaut who spent nearly a year on the International Space Station from
09:582015 to 2016, Scott Kelly.
10:02Like other astronauts, Mr. Kelly served as a test subject in the study of space travel's effects on the human
10:08body.
10:09Unlike other astronauts, Mr. Kelly has an identical twin, Mark, who is an astronaut himself.
10:14This gave researchers an uncommon opportunity to monitor the two brothers as they lived in two very different environments,
10:21one on Earth and the other, 250 miles above it.
10:26When the astronaut went into space and his slightly older twin brother Mark stayed on Earth,
10:31the age gap between them increased thanks to his time in orbit.
10:34And it's all down to Einstein's theory of relativity.
10:38What it suggests is that time moves more slowly for objects in motion than it does for a stationary observer.
10:44It also moves more slowly the closer you are to a gravitational mass like Earth.
10:49In other words, we're not all experiencing time at the same rate.
10:53The faster you move and accelerate, the more time slows down.
10:57And because Mr. Kelly has been zooming up to and down from space and orbiting the planet at around 17
11:03,500 miles per hour,
11:05his brother Mark has lived through 0.005 extra seconds.
11:10The brothers were born six seconds apart back in 1964, and now that gap is 6.005 seconds.
11:18This warping of time is known as time dilation, and the Kelly brothers qualify for both aspects of it.
11:25How fast they've been moving in relation to one another, and how close they are to a big object, which
11:30is Earth.
11:31So, depending on our position and speed, time can appear to move faster or slower to us relative to others
11:37in a different part of space-time.
11:40And for astronauts on the International Space Station, that means they get to age just a tiny bit slower than
11:45people on Earth.
11:46That doesn't mean you could spend your life in a basement just to outlive the rest of us here on
11:51the surface.
11:52The effect isn't noticeable on such a small scale.
11:54If you became a basement hermit, then across your entire lifetime, you'd only age a fraction of a second slower
12:00than everyone else above ground.
12:02But your brain might freeze when you think about this.
12:05A watch strapped to your ankle will eventually fall behind one strap to your wrist.
12:10Your head technically ages more quickly than your feet.
12:13Time passes faster for people living on a mountain than those living at sea level.
12:19The classic example for this is the twin scenario.
12:22One twin blasts off in a spaceship, traveling close to the speed of light, and the other stays behind on
12:27Earth.
12:28When the space-traveling twin returns to Earth, she's only aged a couple of years.
12:33But she's shocked to find that her Earth-bound sister has aged over a decade.
12:38Of course, no one has performed that experiment in real life, but there's evidence that it's real.
12:43When scientists launched an atomic clock into orbit and back, while keeping an identical clock here on Earth, it returned
12:50running ever so slightly behind the Earth-bound clock.
12:53Then time gets even more complicated, because time dilation can happen any time.
12:58A good way to think about it is to consider the astronauts living on the International Space Station.
13:03They're floating about 260 miles above, where Earth's gravitational pull is weaker than it is at the surface.
13:11That means time should speed up for them relative to the people on the ground.
13:15But the space station is also whizzing around Earth at about nearly 5 miles per second.
13:20But the reality is that Mark, the brother who's aged a few milliseconds longer, could end up better off in
13:27the long run if Mr. Kelly's extended time in space causes his body to deteriorate faster.
13:33Ten science teams in NASA's twin study examined the brother's astronauts before, during, and after the astronauts' 340 days in
13:41space.
13:41The teams studied each twin's bodily functions, they ran memory tests, and they examined the men's genes, looking what differences
13:49might be due to space travel.
13:52They confirmed that lengthy space travel stresses the human body in many ways.
13:56Space living can change genes and send the immune system into overdrive.
14:01It can dull mind and memory.
14:03Most changes that the astronaut experienced in space reversed once he returned to Earth, but not everything.
14:09The researchers tested him again after 6 months back on land.
14:14Roughly 91% of the genes that had changed activity in space were now back to normal.
14:19The rest stayed in space mode.
14:21His immune system, for instance, remained on high alert.
14:25DNA repair genes were still overly active, and some of his chromosomes were still topsy-turvy.
14:31What's more, the astronaut's mental abilities had declined from pre-flight levels.
14:35He was slower and less accurate on short-term memory and logic tests.
14:40It's unclear whether these results are definitely from spaceflight.
14:44That's partly because the observations are from only one person.
14:48But one thing is sure, time is relative.
14:52Think of it this way.
14:53If a clock is stationary and you are traveling at a very high speed, you happen to pass by this
14:58clock and have a glimpse at it,
15:00you'll see that it's running slowly.
15:02Or maybe, it's completely static.
15:04This is because the speed at which the mechanical functions of the clock are working slower than you.
15:09What you see is the time in the past, while you have already skipped that second and are in the
15:15future.
15:16During this experiment of high-speed traveling, you haven't aged at all,
15:20because all the processes in your body are working at the same speed as you.
15:24After a certain age, your body starts to deteriorate, which eventually leads to a state when it stops functioning.
15:32This aging phenomenon, especially in humans, is caused by a protein structure in the cells called telomeres.
15:38These structures protect our cells from deteriorating.
15:42But with each cell replication, these telomeres start to lose strength, which is called telomere length.
15:47If the telomere length shortens to a certain extent, the cell becomes vulnerable to diseases.
15:54We can say that telomeres are the natural countdown timers in our bodies, which determine when we will expire.
16:00The telomere length can be affected by external factors like stress, which accelerates our timer.
16:06The twin study experiment by NASA included documenting the changes in telomere length of both brothers.
16:13The telomere length of the space brother increased while he was aboard the International Space Station.
16:18Before the mission, both brothers had nearly the same telomere lengths.
16:22Meaning if we ignore issues like mental stress, both brothers should live roughly an equal age.
16:28But while the space brother was orbiting the Earth, he had almost 14.5% longer telomere length.
16:34The space brother was a few years younger than his ground brother, biologically.
16:39Because the telomere length of the space brother resumed to normal when he came back to Earth,
16:44it took almost 190 days after return for the telomere length to restore to expected.
16:50The blood samples from the International Space Station were sent back to Earth for processing.
16:55This means the blood wasn't traveling at the speed of the ISS anymore.
16:59Also, the space-time paradox states that the space brother should be younger upon return.
17:05But the telomere length restored to its original state before the mission.
17:10The space brother was again the same age as his ground brother.
17:15A lack of gravity is the main cause for these intense changes in aging.
17:19Gravity plays an immense role in the majority of our bodily systems.
17:23Take the muscles for example.
17:24Older people's muscles tend to shrink and decline as they age and become less mobile.
17:30Astronauts' muscles react in a similar way because they are barely used.
17:34That's why astronauts staying in space for extended periods of time
17:37use special exercise machines to help reduce this effect.
17:41A similar process takes place in the bones.
17:44After a certain age, people on Earth start to lose mass in their bones,
17:48typically at a rate of about 1-2% a year.
17:51But, in space, those people lose bone mass at a greatly accelerated rate,
17:56as much as 1-2% a month.
17:59Because the astronauts' bodies don't need to support their weight,
18:03the bones begin to decrease production of new bone material
18:06and increase the amount of old bone absorption.
18:09Luckily, their skeletal systems usually return to normal
18:12once they've spent some time back on our blue planet.
18:16If the space brother was shielded from all harms of space,
18:19like radiations, while orbiting the ISS,
18:22then he would have lived longer than his ground brother.
18:25Even though they're saving 0.005 seconds,
18:28astronauts still experience some of the symptoms of a drawn-out aging process.
18:33So the next time you find yourself wishing the weekend would last longer,
18:36stay low to the ground and move really fast.
18:39It won't feel like your weekend got any longer,
18:41but technically, you may gain a teeny-tiny fraction of a second.
18:45You won't need to go to space for this little experiment.
18:50So, you fall right into the heart of the black hole
18:53and prepare for a sad end.
18:56Well, you don't have to.
18:58Falling into a black hole won't necessarily destroy you or your spaceship.
19:03You have to choose a bigger black hole to survive.
19:06If you fall into a small black hole,
19:09its event horizon is too narrow,
19:11and the gravity increases every inch down.
19:14So, if you extend your arm forward,
19:16the gravity on your fingers is much stronger than on your elbow.
19:20This will make your hand lengthen,
19:22and you'll feel some discomfort.
19:23Rather significant, to be honest.
19:26Things change if you fall into a supermassive black hole,
19:29like the ones in the center of galaxies.
19:32They can be millions of times heavier than our sun.
19:34Their event horizon is wide,
19:37and gravity doesn't change as quickly.
19:39So, the force you'll feel at your heels
19:42and at the top of your head will be about the same,
19:44and you can go all the way to the heart of the black hole.
19:48This myth is busted.
19:51The next myth claims we can save the Earth
19:54from a giant asteroid with a big bam.
19:56The familiar plot is that a spaceship
19:59lands on the surface of an asteroid.
20:01A team of astronauts quickly drills a hole in it,
20:04leaves a present there, and flies away.
20:07Then, bam!
20:09As a result, the asteroid may break into several pieces
20:12and continue on its way to Earth.
20:14Well, big chunks of the asteroid fall to our surface,
20:18causing a lot of damage.
20:19So, our mission is failed.
20:22Well, to save Earth,
20:23we need a really big bam.
20:25Not only outside the asteroid,
20:27but right above its surface.
20:29When the boom happens,
20:31the force of the blast pushes the asteroid slightly downward.
20:35Even a slight change in trajectory
20:36would be enough to make the asteroid
20:38fly past the Earth in the future.
20:41Done!
20:42Oh, and if you made a big boom on an asteroid,
20:45you'd never be able to hear its loud sound.
20:47Yeah, we often hear the sound of spaceships
20:50and battle in space in the movies,
20:52but that's just a myth.
20:54Sound is a wave that spreads
20:56because of the vibrations of molecules.
20:58A person claps a few feet away from you.
21:01The sound wave begins to push
21:03the first air molecule next to the clap,
21:06then the third, fourth, and so on,
21:08until the wave reaches your ear.
21:10So, to spread sound,
21:12we need molecules like air or water.
21:14In our atmosphere,
21:16sound waves spread out just fine,
21:18but space is a vacuum.
21:20So, it's nothing here.
21:22You can clap your hands loudly there,
21:24but there just won't be any molecules
21:26that can vibrate and carry that sound.
21:29One more myth about asteroids.
21:31We need to fly a little farther than Mars' orbit.
21:34Whoa!
21:35We're in an asteroid belt,
21:36and we constantly have to dodge
21:38giant rocks and blocks of ice.
21:40We got in some dense asteroid cloud.
21:43Hmm, not true.
21:45The fact is that space is huge,
21:47and the distances are incredible.
21:50All the rocks and debris in the asteroid belt
21:53are only 4% of the weight of the Moon,
21:56so there really aren't that many of them there.
21:59To understand the size of the emptiness in space,
22:02look at the collision of two galaxies.
22:05There are billions of stars in each of them.
22:08If we mix them up,
22:09it's unlikely there will be any collisions even here.
22:13Another myth is that there's zero gravity in our orbit.
22:17Imagine you're in a huge box 10 miles up in the air.
22:21Now, we let go of the box,
22:23and it starts to fall.
22:24You're falling simultaneously with the box
22:27at the same speed.
22:28And now, it's as if you feel zero gravity.
22:32Well, the same thing happens in orbit.
22:34The International Space Station is 250 miles above the Earth,
22:39and it's falling continuously,
22:41though not on the surface of the planet,
22:43but around it in its orbit.
22:46Its speed at this point is about 4.7 miles per second.
22:50It could cross the United States
22:52from the West Coast to the East Coast
22:54in just 8 minutes.
22:55So, the astronauts there are experiencing the same thing.
22:59They're just falling with the ISS at that speed.
23:03Now, let's look at the Moon.
23:05It always looks at us with one side.
23:07This means the Moon has a dark side,
23:09and the Sun's rays never get there.
23:12Well, that's a myth.
23:13The whole point is that the Moon
23:15is gravitationally locked to the Earth.
23:18There are days and nights there, too.
23:20It's just that this rotation
23:22is perfectly aligned with the rotation of the Earth.
23:25So, whenever you look at the Moon,
23:27you only see one side.
23:29Although, there are days when the Sun shines there, too.
23:33So, it's not the dark side.
23:35It's the far side.
23:37And we even have pictures of this place.
23:39And there's one of the biggest craters
23:41in our entire solar system,
23:43the South Pole-Aitken Basin.
23:45It's as wide as two states of Texas.
23:48One myth that turned out to be untrue
23:50is that people have never actually been on the Moon.
23:53This is the original space suit
23:56of the first astronauts who were there.
23:58Look at the sole of the shoe.
24:00Some people claim there's no way
24:02they could have left footprints like this there.
24:04Actually, they could.
24:06On the Moon,
24:07the astronauts wore extra boots over their suits,
24:10and their soles matched the footprints
24:12on the Moon perfectly.
24:14The astronauts didn't grab them
24:16when they left the Moon.
24:17They left a lot of stuff there, too.
24:19They even ripped out the armrests
24:21of the seats of the lunar module
24:23to reduce its weight.
24:24Now, the total weight of human trash on the Moon
24:27is about 187 tons,
24:30including several lunar rovers,
24:32spacecraft debris,
24:34rocket stages,
24:35and lunar probes.
24:36That's like three Boeing 737s.
24:39The next myth is about summer.
24:42The hot season comes because
24:43the Earth approaches the closest distance
24:45to the Sun in a year.
24:47The Sun warms our planet more,
24:49and we all have to go to the beach.
24:51Well, not true.
24:53Let's draw an axis through our planet.
24:56It's slightly tilted on one side,
24:58and winter comes when our planet's axis
25:01is tilted away from the Sun.
25:03But over time,
25:04the axis tilts toward the hot star.
25:07Then its rays shine at such an angle
25:09that it gets warmer.
25:11It's true, though,
25:12that the Earth happens to be
25:13at different distances from the Sun.
25:15This is because our orbit
25:17is not a perfect circle,
25:18but slightly flattened,
25:20an ellipse.
25:21Normally, we think of the distance
25:23to our star
25:23as about 93 million miles.
25:26But that distance may be longer
25:28or shorter than 3 million miles,
25:30depending on which point
25:31in our orbit we pass.
25:34Another myth about the Sun
25:35is that it's yellow.
25:37Well, let's send you into space
25:38for this one.
25:39You look out the window,
25:41and it's white.
25:42The Sun only appears yellow to us
25:45through the filter of our atmosphere.
25:47The composition of the air
25:49and its thickness
25:50just distorts the light of the star.
25:53But stars do come in different colors.
25:56Cooler stars have bright orange
25:57and red colors.
25:58These are usually very old stars,
26:01older than our Sun.
26:02But young and very hot stars
26:04are bright blue.
26:06The Sun is about
26:07in the middle of the spectrum.
26:08You've also heard about
26:10how, if you take your spacesuit off
26:12in outer space,
26:13you'll blow up like a balloon.
26:15Well, our bodies are designed
26:17to function at atmospheric pressure,
26:19like outside.
26:20But space is a vacuum.
26:23Imagine a huge metal barrel,
26:25and we sucked all the air out from there.
26:27Add to that a temperature
26:29of minus 455 degrees Fahrenheit,
26:31and you have space.
26:34If you could get into those conditions,
26:36all the air pockets in our body,
26:38like our lungs,
26:39would start to expand.
26:40So you really could blow up
26:42like a balloon
26:43if it weren't for our elastic tissues.
26:45They stretch and bend,
26:47so you keep your body sized.
26:49You'll have enough oxygen in your body
26:51to last about 20 seconds.
26:53Then your brain will begin to starve,
26:55and soon you'll pass out.
26:57So you won't blow up,
26:59and you won't even freeze,
27:00because you'll be in a vacuum.
27:02It doesn't conduct heat.
27:03For example,
27:05water conducts heat very well,
27:06and you feel cold from it instantly.
27:09But you feel better
27:10in the air of the same temperature.
27:12If you're in the vacuum of space,
27:15the super low temperature
27:16won't be a problem for you.
27:18Much worse is solar radiation.
27:20On Earth,
27:21we have a shield against radiation
27:23in the form of the atmosphere.
27:25It blocks the harmful rays.
27:27In outer space,
27:28you would be defenseless.
27:30Another myth is related to cell phones.
27:33People think that
27:34when you dial your friend's number,
27:36your phone sends a signal into space.
27:38There are a bunch of satellites out there
27:40that will pick up your signal
27:42and reflect it like a mirror
27:43right into your friend's home.
27:45No, not true.
27:47However,
27:48there are satellite phones in the world
27:50that work that way.
27:51But when you make a cell phone call,
27:53your signal is transmitted
27:55through a system of cell towers
27:57from one to another
27:58until it gets to your friend's phone.