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A portion of new interesting facts about space, as well as answers to questions that may have always worried you!
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00:00You may think the Earth is pretty big, but the Sun makes up almost 99.9% of the mass
00:05of the whole solar system.
00:07The rest of the mass is made up by the planets and their satellites, asteroids, comets, gas, and dust.
00:15It's around 93 million miles away from our planet, but it keeps us warm every day.
00:21Its temperature is about 10,000 degrees Fahrenheit, but the space surrounding it is still cold as ice.
00:27To understand this, we need to distinguish between heat and temperature.
00:32Heat is the energy inside some object.
00:35Temperature is something that tells us if that object is hot or cold.
00:40When the heat is transferred to that object, it makes its temperature go up.
00:44When the object is losing heat, the temperature goes down.
00:48Heat can be transferred in three different ways.
00:51The Sun does it through radiation.
00:53That means it's releasing heat in the form of light.
00:56Your body radiates heat, too, as infrared waves.
01:00That's why thermal imaging cameras will detect that you're in the room even at night.
01:05The hotter the object, the more heat it will radiate.
01:08The temperature only affects matter.
01:11Since space is mostly a vacuum, it doesn't have enough particles for heat to transfer in any other way than
01:17through radiation.
01:18When the heat from the Sun gets to an object, the atoms start absorbing energy, but the heat can't transfer
01:24since there's no matter in space.
01:27Those rare atoms and molecules in space will absorb the heat.
01:31And they'll simply stay that way, while the cold vacuum will stay cold.
01:36There's a lot of matter inside Earth's atmosphere, so the energy of the Sun can transfer easily.
01:42But if you put an object outside of the Earth's atmosphere in direct sunlight, it would end up heated to
01:48250 degrees Fahrenheit, because it's matter made of atoms and molecules.
01:54The temperature of the vacuum is negative 454 degrees Fahrenheit.
01:59That means, depending on where you are, space can either burn or freeze you.
02:04The Sun isn't actually yellow.
02:07It emits light over a wide range of wavelengths.
02:10We can tell both its temperature and color by the peak in its spectrum.
02:15For instance, cooler stars will appear red, and hotter stars will be blue, with yellow, orange, and white stars in
02:22between.
02:23When it comes to the Sun, the spectrum peaks at a wavelength we'd usually call green.
02:29But our eye perceives it differently.
02:31So, the shade of green in combination with other wavelengths from the spectrum is going to look white to the
02:37human eye.
02:38We generally see the Sun as yellow because our atmosphere scatters blue light more efficiently than the red one.
02:45During sunrise and sunset, there's more red light in the spectrum of the Sun, which gives us amazing sceneries.
02:52Sunspots are part of the Sun's visible surface that are on average way cooler than the Sun itself.
02:59They overlap with parts that have an increased magnetic field.
03:02These parts don't allow the release of heat to the Sun's visible surface.
03:06That way, the rest of the Sun's surface is three times brighter than those sunspots.
03:13That contrast makes them appear almost black.
03:16If we could take a sunspot apart from the Sun and place it somewhere in the night sky, it would
03:21be different, as bright as the Moon when we see it from the Earth.
03:25All the planets in our solar system spin in the same direction because they were formed from one protoplanetary cloud,
03:32except for Uranus and Venus.
03:34Yes, they have probably had some strong impact on them that made them spin in the opposite direction.
03:40But it's different with galaxies.
03:42They don't usually form the same cloud of dust and particles.
03:46Also, they're not randomly distributed across space.
03:50They come in filaments, dense, slender strands of dark matter and galaxies, with voids in between.
03:58Protogalaxies are linked by gravitational forces in small areas of space.
04:02This is probably because of the distribution of dark matter throughout the universe.
04:07The matter in the filaments moves in a corkscrew motion and goes towards the densest area.
04:14So, there might be a common direction galaxies tend to spin, but it's mostly random.
04:19There's a possibility we'll see a lunar elevator one day.
04:23Yep, a cable anchored to the surface of the Moon.
04:26It would stretch 250,000 miles.
04:29We wouldn't be able to directly attach it to our planet because both Earth and the Moon are moving.
04:36But, we could keep it terminated high in our planet's orbit.
04:40Some researchers believe we could build such an elevator for a few billion dollars.
04:45The Moon has resources we could definitely use.
04:48A rare form of helium found there could be of use in fusion power stations on our planet.
04:55Also, we could take some other rare elements and use them in smartphones and the rest of electronics.
05:01So, after around 53 trips up and down, the elevator could pay for itself.
05:06The cable would be as thick as a pencil, but its weight would be around 40 tons.
05:12It could even be made of materials we already have here on Earth with no need to invent something.
05:18There could even be a combination of two elevators.
05:22A spacecraft would winch up an elevator from the surface of our planet to a space station.
05:27Then, it would be flung towards the Moon.
05:30There would be another elevator to finally lower it down to the surface of the Moon.
05:35Planets in our solar system have predictable and stable orbits.
05:39But gas giant collisions could have happened at an early stage when a planetary system was still forming.
05:46In case of a head-on collision, two gas giants would merge.
05:50They wouldn't end up losing their mass, the materials in their gaseous envelopes, or the ones in their solid cores.
05:57Such a collision at a higher speed would cause the loss of the major part of the envelope gas.
06:03And very high speeds, boom, both planets are gone.
06:07It's different if it's not a head-on collision.
06:10If two cores manage to completely avoid each other, gas giants won't merge, but they'll lose some of the mass.
06:16Gas giants might even change their shape due to such collisions.
06:22Astronomers found out there's a galaxy, extremely far away from us, that looks similar to our Milky Way.
06:28We now see it as it was when the Universe was only 1.4 billion years old.
06:34And now, it's 13.8 billion years old.
06:37It took over 12 billion years for the light to come from this faraway galaxy and reach our planet.
06:44This galaxy is peaceful, stable, and surprisingly, non-chaotic,
06:49unlike all other galaxies that were quite turbulent in their early stages.
06:54To leave the Milky Way, we'd have to travel around 25,000 light-years away from the center of the
07:00galaxy,
07:00or 500 light-years vertically.
07:03Our galaxy is a disk of stars that spreads around 100,000 light-years across,
07:09and is 1,000 light-years thick.
07:11The Sun, its central star, is located halfway from the center of the galaxy
07:16and close to the middle of the disk in the vertical direction.
07:21We'd have to go further than its edge to get away from the halo that surrounds the Milky Way,
07:26old stars, diffuse gas, and globular clusters.
07:30If you wanted to go even further to see the Milky Way, in all its glory,
07:35you'd have to travel 48,000 light-years vertically.
07:38At this moment, we don't even have a telescope we can send there.
07:42There are central stars that eat planets.
07:46Our solar system is stable, unlike many other planetary systems.
07:50So we don't have to be afraid the Earth or some other planet will change its orbit and go towards
07:55the Sun.
07:55But, at least a quarter of other planetary systems with orbiting stars similar to the Sun
08:00have a pretty chaotic past.
08:03In some of them, there are planets that used to move around,
08:06and their unpredictable migrations have disrupted the paths of some other planets,
08:11or even pushed them outside of their orbit.
08:13That means some planets probably have fallen into the central star.
08:18When that happens, the planet gets dissolved in the outer layer of the star,
08:22which means it gets eaten.
08:26Humanity will once again visit the Moon.
08:28The mission is planned for 2024.
08:31In this crew, we'll see the first women step on the Moon.
08:34The main goal is to establish a lunar base for continued research
08:38that will help NASA prepare for an upcoming mission to Mars.
08:44NASA has been planning a crewed flight to the Red Planet set for the 2030s.
08:49Robotic rovers did a good job exploring the Martian surface,
08:52but astronauts will have to dig deeper to find evidence of water
08:56and any fossils proving microscopic life was once possible on our planetary neighbor.
09:02New data on Earth-like planets.
09:05Since its launch in 2009,
09:08the Kepler Space Telescope has discovered lots of exoplanets orbiting distant stars.
09:13Some of them have an Earth-like mass, composition, and orbits.
09:18NASA plans to launch a new generation of telescopes in the 2040s.
09:22They'll help us find real twins of our planet and even get pictures of their surfaces.
09:29The return of Halley's Comet
09:31It'll be another 41 years before we once again see the most famous comet in the sky.
09:38Halley's visits us every 75 years,
09:41so some will manage to see it twice in their lifetime.
09:45The longest solar eclipse
09:48166 years from now,
09:50I'll still be around then,
09:51the Sun will go dark for 7 minutes and 29 seconds.
09:56This is pretty close to the predicted maximum.
09:58It'll also be the longest eclipse human civilization has ever witnessed in its 10,000 years.
10:06Arrival of the Most Notorious Asteroid
10:091950 DA was once the most probable candidate among near-Earth objects we know
10:16to actually strike the planet.
10:18Fortunately, the chance was later estimated to be not even a tenth of a percent.
10:23It'll most likely pass by on March 16th, 2880.
10:28Mark your calendars.
10:29And it'll become a solid evidence that we're safe for a while.
10:33The asteroid is more than a mile in diameter,
10:36enough to take out life on a planet.
10:39A new north star?
10:41The Earth spins like a top.
10:44Watch one of these toys closely,
10:45and you'll see how its tip starts to draw circles in the air.
10:49The Earth's axis, an imaginary line going through the poles,
10:53goes full circle once every 26,000 years.
10:57It points at different stars along the way,
11:00thus changing the north star.
11:01By the year 3000,
11:03the Gamma-Sephi star will share this title with Polaris,
11:07as the Earth's axis will point right between them.
11:14Antares is the 15th brightest star in the night skies.
11:18It's also an old red supergiant,
11:2112 times larger than the Sun.
11:23Stars this massive age to a point where they collapse in on themselves,
11:28producing huge supernovas.
11:29For Antares, this will happen just 10,000 years from now,
11:33which is nothing for a 12-million-year-old star.
11:36The resulting burst will be too far away to affect life on this planet negatively.
11:41But the light show will be visible here on Earth,
11:44even during the day.
11:47Message to the Universe
11:48Delivered
11:50Arecibo is the encoded message describing humanity,
11:54life on Earth,
11:54and the advancement of our scientific knowledge.
11:57It was broadcast from the Arecibo radio telescope
12:00and aimed at the center of the M13 cluster 25,000 light-years away from us.
12:06In 25,000 years, it'll finally reach its destination.
12:11A new closest star
12:14About 36,000 years from now,
12:16the Ross 248 star will become our new closest neighbor.
12:21It'll be just three light-years away from us
12:23and overtake the title from Proxima Centauri,
12:26which is a bit more than four light-years away.
12:29Ross 248 will remain the nearest star for around 9,000 years
12:33and then move away once again.
12:36So, you didn't like the neighborhood or what?
12:39The first interstellar human-made object
12:42In 40,000 years,
12:45Voyager 1 will reach a point within 1.5 light-years
12:48of the Gliese 445 star.
12:51It successfully reached interstellar space in 2013.
12:54But, unfortunately,
12:56it won't be able to power up any of its systems
12:59somewhere beyond the year 2025.
13:01Voyager 1 has a message, too.
13:04A recording of greetings in 55 languages,
13:07music from classical to rock and roll,
13:09and sounds of the Earth's wildlife.
13:12A bare Saturn
13:14100,000 years from now,
13:16Saturn will lose its beautiful rings.
13:19It'll happen gradually over time
13:21as the planet's colossal gravity
13:23pulls rocks and ice from this belt floating around it.
13:27They'll all eventually fall
13:28and get crushed and burned by Saturn's atmosphere.
13:31Well, how rude!
13:33The ring system is in the middle of its life cycle,
13:36so we're incredibly lucky we got to see it in its full glory.
13:40The most frightening supernova
13:42The WR-104 star will burst into a supernova in 3,000 years.
13:49This star is 75,000 light-years away from us,
13:52and the blast won't touch us at all.
13:54But there is a small chance
13:56it'll also produce a gamma-ray burst in the process.
14:00If this stream of energy happens to aim right at us,
14:03it will negatively affect life on Earth.
14:06Good news?
14:07Scientists say that's very unlikely.
14:11Colliding moons
14:12The moons of Uranus are part of a highly unstable system.
14:17Some of them have orbits that cross paths.
14:20Uranus already has two rings of debris
14:22from past collisions of its natural satellites.
14:25Desdemona and Cressida will crash into each other
14:28in the next million years and produce new rings.
14:32A star too close for comfort
14:35The rogue Gliese 710 star is approaching our solar system,
14:39and it will get just one light-year away in 1.3 million years.
14:44This won't have a major impact on the planets,
14:47but it could disturb the so-called Orch Cloud,
14:50which surrounds our solar system and is full of comets.
14:53From Earth, the star will look like the brightest planets we see now,
14:57and we'll see many more comets in the skies.
15:01The closest star to ever-go supernova
15:04Within a few million years, the Spica star,
15:07which is only 240 light-years from us,
15:10will burst into a supernova.
15:13Supernovae are a problem for life when they're three times closer than that.
15:17But the supernova itself will shine in the Earth's skies as bright as a full moon.
15:23A time capsule for future generations
15:25The Lagios 1 satellite was launched back in 1976
15:30to gather information about the exact shape of the Earth
15:33and tectonic plate movement.
15:35But it also contained information about civilization on Earth at the time.
15:40It'll re-enter our atmosphere in 8.4 million years.
15:43If humanity is around then,
15:45they'll learn how life on Earth was in our time.
15:48Well, at least how it was some 40 years ago.
15:52Rings for Mars
15:54Mars' moon, Phobos, orbits really close to the surface,
15:58and it continues to get 2 feet closer every century.
16:0250 million years from now, it'll collide with Mars,
16:05resulting in a massive amount of debris going into orbit
16:08and forming a ring system around the Red Planet.
16:12Oh, can't wait for that.
16:15Days on Earth will get longer.
16:17No, really?
16:181.4 billion years ago, the moon was much closer to our planet.
16:23It made the Earth rotate faster.
16:25So the day was only 18 hours.
16:28The moon is continuously moving away from Earth.
16:31In 180 million years,
16:33we'll gain one extra hour.
16:36In a little over 2 billion years,
16:38a day on Earth will be 36 hours long.
16:42No more solar eclipses.
16:44600 million years into the future,
16:47the moon will move away from the Earth too far
16:49to cover the sun during eclipses.
16:51Those will become ancient relics.
16:55The sun will get too bright.
16:57It'll take about a billion years for the sun
17:00to raise its luminosity by 10%.
17:02This will be devastating for planets in the solar system,
17:06and life on Earth won't be possible beyond this point.
17:09By then, our species will likely have found a new planetary home.
17:14The sun will swallow the inner planets.
17:17In 5 billion years,
17:19the sun will begin to evolve into a red giant,
17:22growing hundreds of times its current size.
17:24It'll swell up so much,
17:26it will eventually engulf Mercury, Venus, and possibly Earth.
17:30The new Goldilocks habitable zone
17:33may shift to the orbits of Jupiter and Saturn.
17:36This process will take a bit under 3 billion years
17:39until the sun reaches its maximum size.
17:42After that, our star will shrink into a white dwarf.
17:47The most epic event ever.
17:49Around the same time our sun has swelled up,
17:52the nearest neighboring galaxy, Andromeda,
17:55will come too close to the Milky Way.
17:57If we could watch our galactic neighbor at this time,
18:01it'll get larger and larger as it approaches.
18:04Then, the two galaxies will start to merge.
18:07Bright blue stars will burst into life.
18:10New constellations will form.
18:12The two spiral galaxies will now be a single giant elliptical one.
18:17Wow, I've set an alarm on my smartphone so I don't miss it.
18:27It's September 1977.
18:29You're playing one of the first video game consoles
18:32released in North America.
18:33You step outside and see the whole neighborhood
18:36waiting for Voyager 1 to launch.
18:38It's a super sunny day,
18:40so you squint a little, trying to see what's happening.
18:43You live in the neighborhood right outside the launching station.
18:46You get yourself some food
18:48and watch the Voyager take off into space.
18:51You're so impressed,
18:52you decide to dedicate your career to working with NASA.
18:5735 years later.
18:59You're now a senior official in NASA,
19:01specializing in Voyager 1.
19:04It's 2012,
19:05and you're sitting in the control room with your colleagues.
19:08Everyone is staring at their computer screens
19:10as they work on the Voyager.
19:13You're sitting on the top,
19:14overlooking everything
19:15and making sure all systems are in check.
19:18This day is special,
19:20as Voyager 1 is about to exit the heliosphere,
19:23which is a science word
19:25for the outer shell of our solar system.
19:27It's a bubble of space,
19:29affected by the solar wind,
19:31which comes from the sun.
19:33By 2021,
19:34it got 14 billion miles away from Earth,
19:37which is equivalent to 153 astronomical units from the sun.
19:42One astronomical unit
19:43is the distance between the sun and the earth.
19:46The craft was originally meant to fly by Uranus,
19:50Saturn,
19:50and Jupiter,
19:51and toss itself from one planet to another
19:54with the use of their gravitational pull.
19:56Everyone is impatiently waiting for it to exit the heliosphere.
20:01Three,
20:02two,
20:03one,
20:03and it's officially out!
20:05All systems are normal and functioning.
20:07You praise your team for doing an excellent job.
20:11With Voyager 1 reaching this far,
20:13there's still tons to explore in outer space.
20:16You were once a young adult,
20:18watching the craft launch outside your neighborhood.
20:21And now,
20:22you're the main person in charge of the operation.
20:25Nine years later,
20:27Since Voyager 1 left the heliosphere,
20:30you've been checking up on it every now and then,
20:33making sure all systems and functions are in order.
20:36It's been sending back measurements of the interstellar medium.
20:39It's the area between the stars of our galaxy,
20:42consisting of ionized materials.
20:45Ionized is basically a simple version of a molecule or substance.
20:49The interstellar medium is an electrically charged state of plasma,
20:53or ionized plasma,
20:55and is very unstable.
20:57It's like going from lightning in a thunderstorm
20:59back to calm rain in a matter of seconds.
21:02The plasma up there is different than the plasma on Earth,
21:06in that it's difficult to filter out.
21:08There are around 0.06 atoms
21:11for every cubic inch in the interstellar medium.
21:14The air we breathe on Earth has billions of atoms.
21:18By measuring the plasma in the interstellar medium,
21:21we can further understand the behavior and structure of chemicals and gases.
21:26It's possible that the oxygen we know and love on Earth is different than the ones out there.
21:32One of your main tasks is to learn more about how the solar wind from the sun
21:37and interstellar medium interact with each other to create the heliosphere.
21:42So, after doing some routine check-ups and other maintenance work on Voyager 1 from the control room,
21:48you notice something strange coming from the screen.
21:51You sit in front of the computer, crunching the numbers of the plasma vibrations,
21:55and convert them into an audio file of about 3 kilohertz.
22:00You click on it and listen to an eerie, subtle hum.
22:03You and your team are surprised that these vibrations occurred in such a small frequency.
22:09Given that space is massive,
22:11something like this might mean life on other planets.
22:15Everyone else at the station rushes to the control room
22:18to listen to that sound from outer space.
22:20It's monotonous and faint,
22:23but it's definitely coming from outside the heliosphere.
22:27You run the numbers over and over to make sure it's not a fluke,
22:31but it's on point.
22:32You make sure your team doesn't spill the beans to anyone outside
22:36until everything is known and clear.
22:39You get into beast mode with work and try to catch the sound again,
22:43and it remains.
22:44You can't sleep trying to think of something that could be producing this hum.
22:48A few days pass by,
22:51and the sound is pretty consistent.
22:53If there was some life out there trying to communicate with you,
22:56then surely it would have said something that can be deciphered.
23:00You analyze the audio files once again,
23:03trying to see if it's some phonetic language you don't know.
23:06You call in a linguist to see if she can make something out of it.
23:10You and the squad gather around,
23:12waiting impatiently for some answers.
23:15After a while,
23:16she believes that it might be someone out there communicating with us,
23:19but the only way to find out is by sending something back to them.
23:24You arrange a meeting with your team
23:26and try to figure out what message you can send.
23:29After much thinking,
23:30and lots of coffee,
23:32you decide to send them one phrase in English.
23:35Who are you?
23:36You send out the signal through Voyager 1
23:39and wait for any changes in the hum.
23:41But you don't get anything straight away.
23:44It may take some time for a response.
23:47You wait all night,
23:48and still,
23:49there's nothing.
23:50It's starting to look like there isn't anything out there.
23:54For the next couple of days,
23:56you keep sending out phrases for anything to pick up.
23:59Since space is a vacuum,
24:01sound waves can't travel.
24:03So sending out voice messages on a large speaker won't work.
24:07You locate the source of the humming
24:09and aim for it when sending the audio file.
24:12Every day,
24:13you send something different.
24:14But still,
24:15you don't hear anything from them for a week.
24:18It seems that intelligent life in the distant world isn't real.
24:22The areas between the star systems in a galaxy
24:25aren't necessarily a complete vacuum.
24:28That's where the interstellar medium is.
24:30It contains gases,
24:32dust,
24:33and cosmic rays,
24:34which are energy particles.
24:36After many months of this constant humming being produced,
24:39you still try to figure out what's going on.
24:42You sit there,
24:43remembering the time when the Voyager was first launched.
24:46You remember running outside after playing some video games.
24:50You couldn't see properly because of the sun,
24:52and...
24:53You freeze in your spot
24:55and have a eureka moment.
24:56You go through some notes taken in the past.
24:59The answer was in front of you all this time.
25:02Every now and then,
25:03the sun sends a burst of energy
25:05that causes the plasma of interstellar space to vibrate.
25:10Scientists can measure the frequency of waves
25:12when the plasma vibrates
25:13to show how close they are to each other.
25:16And on the day when the hum was delivered,
25:18there were some irregular frequencies coming from the sun.
25:21So that hum might have been the plasma vibrating in a weird way
25:26because of the sun flares.
25:28But these low-level vibrations last longer than quick jumps and spikes.
25:33They're fainter.
25:34You run the tests again
25:36and find out that it's not some intelligent lifeforms out there
25:39trying to talk to you.
25:40It's the little vibrations caused by sun flares.
25:44You notify your team about this breakthrough
25:46and everyone's celebrating.
25:48But after all these tests and research,
25:51you still don't know
25:52why plasma in the interstellar medium vibrates in such a way.
25:56Those answers will have to wait.
25:592027.
26:00It's been 50 years since the launch of Voyager 1.
26:04You're way into your senior years
26:06and just retired from NASA.
26:08You have many scholarships in your name
26:11and programs for young people
26:12who want to learn about space and science.
26:15You go back to the control room once more
26:18where you thought you had discovered
26:19intelligent life on a distant world.
26:22Then you remember all the good times you had.
26:25You say goodbye to everything
26:27knowing that this is Voyager's final moments.
26:30It was built to last up to 50 years.
26:33After that,
26:34it'll just be a floating object in the vastness of space.
26:38It's already surprising to know
26:40that this is Earth's most distant object from us.
26:43But it's time to let others take your place.
26:46You shut off the lights and close the door.
26:49The Voyager makes one last beep
26:51before eternal silence.
26:53You get a moment of silence.
26:56The Voyager 1.