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A piece of the Moon is drifting close to Earth, the North Star is acting strangely, and scientists are rushing to place clocks on the Moon. What’s really going on in space?
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00:00An asteroid broke off the moon and now it's super close to Earth.
00:04Does it pose a danger to us?
00:06Kama'o'olewa, also known as 2016 HO3, spins super quickly as it orbits near our planet.
00:14Let's call it HO3 for short.
00:17Astronomers found it on April 27, 2016.
00:21Compared to other asteroids, it's tiny.
00:24On Earth, though, it would be the size of a small building, or about half the size of the London
00:29Eye Ferris wheel.
00:30They discovered it in Hawaii, and its name roughly translates to a fragment of something that seems to wobble.
00:37After some study, they realized that this asteroid might be a chunk of the moon that got blasted into space.
00:44There's a part of the moon called Giordano Bruno Crater, named after an Italian philosopher, that guy who had to
00:51pay quite the price for his ideas.
00:54If you look at it from space, Giordano Bruno stands out because it's surrounded by some rays of material.
01:00They're super huge, stretching over 93 miles, and are still bright.
01:04This means that an enormous boom once happened there.
01:08There's an interesting story about this.
01:10In 1178, five monks were traveling in Canterbury, England.
01:15Suddenly, they saw something strange happening on the moon.
01:18They said it looked like the moon was splitting, with flames and sparks.
01:21Then, there was a darkening that spread all across the lunar surface.
01:26In the 20th century, scientists found these records and thought that these monks saw the formation of the Giordano Bruno
01:33Crater.
01:33But later, it turned out that the crater is about 4 million years old.
01:38And thank the stars, because such a massive impact, if it really happened in the 12th century, would have gone
01:44crazy on our planet.
01:45It would have caused a huge meteor storm on Earth.
01:48In any case, our HO3 is most likely a piece of the moon that broke off during that impact 4
01:54million years ago.
01:55Luckily, there's no need to panic about it.
01:58When astronomers spotted this sudden moon piece, they quickly tracked its orbit.
02:02Turns out, it won't collide with us anytime soon.
02:05It's going to be our quasi-satellite for at least 300 more years, meaning it'll follow a path around the
02:12sun that keeps it close to Earth without colliding.
02:15Its orbit is wild, though.
02:18It seems to be constantly looping around our planet in some pretty unique loops, moving closer and going away, up
02:24and down.
02:25And then somewhere in the 24th century, it will go even more crazy, switching to a horseshoe orbit, slowly going
02:33away from us.
02:34Could HO3 collide with us someday?
02:37Maybe.
02:38But that would happen over millions of years, when it would leave its current orbit and collide with Earth, Venus,
02:44or even the Sun itself.
02:46Or maybe entirely ejected from the solar system.
02:49Even though it's one of the closest asteroids ever discovered, it's also one of the smallest and most stable ones.
02:56This discovery also opens up some exciting ideas about life in the universe.
03:01We see that rocks can travel between celestial bodies.
03:04There is a theory that life could have been spread all across the universe by traveling on these rocks like
03:11on some space Ubers.
03:13Or at least the building blocks of life like carbon.
03:16Maybe life even hitchhiked to our planet on rocks from Mars.
03:20HO3 probably doesn't carry any life, but the fact that it can travel for millions of years carrying stuff on
03:27it and feeling fine supports this theory.
03:30Astronomers want to send something to investigate HO3.
03:34Back in 2017, a group of students gave an idea of using a spacecraft for it.
03:39The China National Space Administration wants to send a robotic probe to HO3 somewhere in 2025.
03:47The robot should fly there, collect samples, and bring them back to Earth for study.
03:53Unfortunately, you can't see this asteroid in the sky with the naked eye.
03:57Its size is about 130 to 330 feet in diameter, so it would be too tiny and dim to see
04:05without a super powerful telescope.
04:08But there is an asteroid that you'll be able to see, and it will be insane.
04:14In 2029, a large asteroid will pass so close to Earth that it will be visible to the naked eye.
04:20Make sure not to miss it, because this is a once-in-a-thousand-year event.
04:24The asteroid is known as 2004 MN4, or Apophis for short.
04:31It's much bigger than HO3, about 1,210 feet wide.
04:36This will be the closest asteroid passage ever.
04:40This one actually caused some panic back in December 2004.
04:44All because there was a 2.7% chance that it could hit Earth in 2029.
04:50People were horrified.
04:52Even the name, Apophis, is inspired by an evil serpent from ancient Egyptian mythology.
04:57A huge monster that fought Ra and always tried to swallow the sun and destroy the planet.
05:04Luckily, when scientists got more data, they realized that it would pass pretty close to us in 2029,
05:10and we'd be able to see it in the sky.
05:13But then, it will just fly away like a chill asteroid.
05:17There was another worry, though.
05:19That during its close pass, Apophis might travel through something called a gravitational keyhole.
05:26Basically, that it could travel through a specific narrow region of space which would accidentally alter its orbit.
05:33And then, it would make an epic comeback in 2036, like the planet from the movie Melancholia.
05:40However, after some calculations, scientists ruled out this possibility as well.
05:46Apophis will still come quite close to us in 2036, but it will be about as far away as Venus
05:51is when it overtakes Earth.
05:53And then, Apophis and Earth will just go their own separate ways.
05:58On average, an asteroid the size of Apophis is only expected to hit Earth once every 80,000 years.
06:05And if it did hit us, it would completely destroy a huge area, causing earthquakes and tsunamis all around the
06:12world.
06:12But it wouldn't cause an apocalypse or anything like that.
06:16You'd only be able to see Apophis from Europe, Africa, and Western Asia.
06:20So, if you want to see it, you might need to travel.
06:23The asteroid will look like a fast-moving star in the night sky, shining bright enough to be seen without
06:29any special equipment.
06:31It would be easy to spot at night, though city lights might make it harder to see.
06:37Now, can you imagine that these are not the only guys hanging nearby?
06:42Both H-O-3 and Apophis are part of the so-called Apollo Orbit asteroids.
06:47These are the asteroids with orbits going around Earth, an entire group of dangerous fellas.
06:53Since they cross Earth's orbit, they have the potential to come close to or even collide with our planet.
07:00The first asteroid of this group to be discovered was 1862 Apollo, named after the Greek deity of the Sun.
07:07It was first discovered in 1932, and the group was named after it.
07:12This one was even bigger, almost a mile in size.
07:17In fact, it's so huge that it even has its own tiny moon.
07:21Apollo crosses orbits of not just Earth, but also Venus and Mars.
07:27Fun fact, even though it was the first one of its kind, telescopes accidentally lost it out of view for
07:34over 40 years.
07:35So scientists went, oh well, let's just keep the count of things we can see.
07:40When Apollo was rediscovered, in 1973, it wasn't the first asteroid on the list, and got a big number in
07:48its name.
07:49Apollo will fly near us during the next hundreds of years.
07:53In 2075, it will be somewhere around Venus, but it should fly by as well.
07:58In any case, there's no need to worry, because astronomers are keeping a close track on these guys.
08:04If we were in any immediate danger, we'd have known.
08:08In order for an asteroid to totally destroy life on our planet, it should be bigger than 6 miles in
08:13diameter.
08:14Like the one that helped to wipe out the dinosaurs 66 million years ago.
08:19But these guys are so crazy rare, we'd probably live on other planets by the time they arrive on Earth.
08:28Locating the North Star is quite easy on a clear night.
08:31The only thing you need to do is find the Big Dipper.
08:34Those two stars on the end of the Dipper's cup point the way to the North Star.
08:39See? It's the tip of the handle of the Little Dipper, or the tail of the Little Bear.
08:44It's in the constellation Ursa Minor, over there.
08:48People have been watching the North Star for centuries.
08:51This bright star is also known as Polaris.
08:54It's situated almost directly over our planet's North Pole,
08:58which makes it a great landmark for a traveler without a compass, or a GPS on their smartphone.
09:04It's also Earth's close to Cepheid.
09:07That's what we call a star that pulses regularly in brightness and diameter.
09:12Polaris is also part of a binary system of two stars.
09:16It's got a dimmer sister.
09:17It's known as Polaris B.
09:19You can actually see it circling the North Stars from Earth.
09:24But the more astronomers watch Polaris, the less they understand.
09:29The problem is, no one can agree on how big or distant the star is.
09:34Scientists have several ways to estimate the mass, age, and distance of a star like Polaris.
09:40One method is called the Stellar Evolution Method.
09:43After studying the brightness, color, and rate of pulsation of a star,
09:48experts use this data to figure out how big or bright it is,
09:52as well as what stage of life it's in.
09:55Once these details are clear, it's not hard to find out how far a star actually is.
10:00It's simple math once you know the luminosity of a star in real life
10:04and how dim it looks from our planet.
10:07Such models are especially precise for stars like Polaris
10:10because the rate of their pulsing is directly related to their brightness.
10:14This makes it easy to figure out the distance to any of those stars.
10:19Astronomers trust this method so much
10:21that Cepheids have become an important tool for measuring distances all across the universe.
10:27At the same time, there are other ways to study the North Star,
10:30and they don't agree with the Stellar Evolution models.
10:33Polaris is a so-called astrometric binary.
10:38It means you can see its companion going around it.
10:41It looks as if a circle is being drawn around the bigger star.
10:45To complete one orbit, the smaller star needs around 26 years.
10:50Even though astronomers haven't made detailed observations of Polaris B's full circuit,
10:55they've seen enough to know what its orbit looks like.
10:59Using this information, one can apply Newton's laws of gravity
11:02to calculate the masses of the two stars.
11:05Combined with the Hubble Space Telescope's new measurements,
11:08these calculations lead to very precise numbers.
11:11Polaris is supposed to be around 3.45 times the mass of the Sun,
11:16but that's much less than the mass you get from Stellar Evolution models.
11:20They suggest a value of almost 7 times the mass of the Sun.
11:25But there's another reason why this star system is weird.
11:28After calculating the ages of the stars,
11:31researchers concluded that Polaris B is much older than its bigger sibling.
11:36But it's extremely unusual for a binary system.
11:39Normally, both stars are of the same age.
11:43One explanation might be that at least one of the measurements is simply wrong.
11:48After all, Polaris is a difficult star to study.
11:50Since it's positioned above our planet's north pole,
11:54it's outside the field of view of most telescopes.
11:57As for those telescopes that do have the needed equipment
12:00for measuring the star's properties precisely,
12:02they're typically used for studying much more distant and fainter stars.
12:07Polaris is simply too bright for such instruments.
12:10It blinds them.
12:12There's a theory that the main star of the Polaris system was once two stars,
12:16but they collided a few million years ago.
12:19Such a binary collision could rejuvenate stars by pulling in extra material
12:23and making the stars look as if they went through the Fountain of Youth.
12:27It would also explain some other oddities,
12:30since stars that appear as a result of binary collisions
12:33don't fit stellar evolution models.
12:36Unfortunately, so far, none of the theories have been confirmed.
12:40The North Star is actually a big deal.
12:44Earth is spinning non-stop,
12:45which causes the Sun to rise and set and stars to travel across the sky.
12:50Our planet is also tilted.
12:53That's why we have seasons.
12:54If we drew a line through the axis Earth spins around
12:58and extended it over 300 light-years past the North Pole,
13:02at the end of that imaginary line,
13:04there would be the North Star.
13:05It stays almost exactly at the same spot in the sky at all times
13:10and always points the way north.
13:12It's really important for navigation.
13:14People heavily relied on it in the days before GPS.
13:18If you were standing on the equator,
13:20Polaris would be right at the horizon.
13:22At the North Pole, it would seem to be right over your head.
13:26In other words, using the star's height in the sky,
13:29you can not only figure out the needed direction,
13:31but also understand where you are on Earth.
13:35Curiously, there's no South Star.
13:37There isn't a bright enough star right above the South Pole,
13:40but one day we might get such a star.
13:43When you spin a top on the table,
13:45its end moves in a circle.
13:47We know this phenomenon as precession.
13:50Earth behaves in the same way,
13:52and the North and South Poles won't always point towards the same spots in the sky.
13:56In the next 26,000 years,
14:00it may cause the North Star to change from Polaris
14:02to a few other stars and back again.
14:05One day, the title of the North Star will go to Vega.
14:09It's the fifth brightest star in the night sky
14:11and the second brightest in the Northern Celestial Hemisphere.
14:15Vega has another name, Alpha Lyrae.
14:18That's because it's the main star of the Lyra constellation.
14:21Vega has been one of the most crucial stars to people since ancient times.
14:25It's very bright and blue, hence, very recognizable.
14:30Vega was the North Star several thousand years ago,
14:33and it'll regain this status in 12,000 years or so.
14:37This star is located a mere 25 light-years from Earth.
14:41It's just 450 million years old,
14:43which makes it way younger than our own 4.6 billion-year-old star system.
14:49Astronomers study Vega to learn more about star systems
14:52in the early stages of their formation.
14:54Vega is almost directly overhead at mid-northern latitudes on a summer night.
14:59It hides behind the horizon for only 7 hours a day.
15:03You can see it on any night of the year.
15:05If you travel farther south,
15:07you'll find out that Vega lies below the horizon for longer periods of time.
15:12But in Alaska, northern Canada, and some parts of Europe,
15:16Vega never sets.
15:18Vega's blue-white light is bright enough to be featured a lot in ancient cultures,
15:22from the Chinese to the Polynesians to the Hindus.
15:26Vega's name can also be translated as fallen or swooping.
15:31This is a reference to the times when people regarded this constellation
15:34as a swooping vulture, not a leer.
15:38Vega was also the first star to get photographed,
15:41other than the sun, of course.
15:42To do it, astronomers at Harvard College Observatory used a 15-inch refractor,
15:47and it happened again in 1850.
15:50Around two decades later,
15:52an amateur astronomer broke down Vega's light
15:54to reveal various elements making up the star.
15:57In 2006, thanks to telescopic observations,
16:01scientists found out that Vega was whipping around so fast
16:05that its poles were several thousand degrees warmer than its equator.
16:08The star rotates every 12.5 hours and is at 90% of its critical rotation speed.
16:15That's the velocity at which an object can tear itself apart.
16:19In 2013, researchers announced that they had discovered an asteroid belt around Vega.
16:25It means there might be planets somewhere out there among space rocks.
16:30There are two areas,
16:31an outer region that contains icy asteroids
16:34and an inner region with warmer space rocks.
16:38Scientists can examine bright stars like Vega
16:41using NASA's mission called TESS,
16:43which stands for Transiting Exoplanet Survey Satellite.
16:48It was launched in 2018 to conduct an all-sky survey.
16:52The main goal of this mission is to search for exoplanets,
16:55but the satellite can also look for star variability.
16:59By examining such stars as Vega,
17:02TESS can help scientists learn more
17:04about the early stages of star evolution.
17:07Time can stretch or shrink depending on where you are.
17:11Climb to the top of an extremely high mountain,
17:14and time will pass a teeny tiny bit faster
17:17than if you were down in a valley.
17:19That's all because of gravity and how it affects time.
17:22We hardly notice it in our everyday life,
17:25but for scientists and space agencies
17:27preparing to send people to the moon,
17:29these minuscule differences in time really do matter.
17:32We'll get to answer the why question a bit later.
17:39Right now, a new space race is underway.
17:43Many countries want to establish long-term bases on the moon.
17:46With humans up there,
17:48things like reliable timekeeping become crucial.
17:51The thing is, the moon doesn't operate on Earth's time.
17:54A day on the moon runs slightly faster than a day on Earth.
17:58The difference is about 56 microseconds,
18:01and it seems insignificant.
18:03But over time, even such a difference can add up,
18:06creating bigger issues.
18:08So, to keep lunar missions running smoothly
18:11and prevent things from drifting out of sync,
18:14NASA and scientists around the world
18:16are now dealing with a tricky challenge,
18:18creating an entirely new lunar timescale.
18:23NASA is supposed to start using it by 2026.
18:26It's the same year they hope to send astronauts back to the moon
18:29for the first time in 50 years.
18:31But this new timescale is not just a moon time zone.
18:35It's actually an entire system
18:37that will adjust for the moon's faster time
18:39and keep everything synchronized with Earth's time systems.
18:43Only in this case will missions be able to run smoothly.
18:46You see, on Earth,
18:47our timekeeping is already surprisingly complicated.
18:50It might seem like time should be a straightforward concept,
18:54but keeping accurate time is actually a precise science,
18:57especially when you consider
18:59how much timekeeping affects our daily lives.
19:02So, to keep global time coordinated,
19:05scientists rely on something called
19:06Coordinated Universal Time,
19:08also known as UTC.
19:10This global time standard is based on
19:13ultra-precise atomic clocks
19:15that scientists place in separate locations
19:17all over the world.
19:18Atomic clocks are cool,
19:20because they measure time
19:21based on the consistent vibrations of atoms.
19:24So, they're super-stable and accurate.
19:27This helps scientists make sure
19:28UTC is the same for everyone, everywhere.
19:32These atomic clocks also take into account
19:35that time moves slightly more slowly
19:37the closer you are to the center of our planet.
19:40So, atomic clocks,
19:42positioned closer to the Earth's surface,
19:44tick a bit more slowly
19:45due to stronger gravitational pull.
19:47This effect,
19:48explained by Einstein's theory of relativity,
19:51happens because gravity affects time.
19:54By spreading atomic clocks
19:55across different elevations,
19:57scientists average out
19:58all the tiny time differences
20:00caused by gravity.
20:01Also, for precise timekeeping,
20:04scientists occasionally add leap seconds
20:06to account for the small natural changes
20:08in Earth's rotation speed.
20:10It sounds pretty technical,
20:12but this process of keeping everyone
20:14on the same time
20:15helps make the modern world function.
20:17After all,
20:18precise timing is crucial
20:20for global trading,
20:21GPS navigation,
20:22and even internet communications.
20:25But, time on the Moon works differently.
20:27Our natural satellite
20:29has a weaker gravitational field than Earth.
20:31That's why clocks on the Moon
20:32tick a bit faster.
20:34This difference means that lunar clocks
20:36are very likely to slowly drift away
20:38from Earth clocks
20:39if there's no correction.
20:41It can lead to big problems
20:43when astronauts need to keep
20:44in close contact with Earth
20:46or navigate around the lunar surface.
20:48NASA's solution is something called
20:50a lunar time scale.
20:52Scientists aren't going to adjust
20:54moon clocks to match Earth exactly.
20:56Instead, they want to establish
20:58a unique system
20:59that measures lunar time accurately,
21:01but is also easy to convert
21:03back to Earth time.
21:04Think of it as creating
21:05a whole new framework
21:07just for the Moon.
21:08To make this lunar time system work,
21:11NASA is cooperating
21:12with international colleagues
21:13like the European Space Agency.
21:16Together, they're setting up
21:17what they call Lunanet.
21:19This lunar network
21:20will be a bit like
21:21the internet for the Moon.
21:22It'll make sure
21:23all the lunar clocks work together
21:25and align with Earth-based time.
21:28Just like how atomic clocks
21:29around the world
21:30coordinate for UTC on Earth,
21:32clocks on the Moon
21:33will be part of this larger
21:35Lunanet network.
21:37Scientists are pretty experienced
21:38when it comes to managing
21:39time and space.
21:41Global positioning system satellites,
21:43which orbit Earth
21:44about 12,550 miles high,
21:47have atomic clocks on board.
21:49These clocks tick faster than clocks
21:51on the Earth's surface
21:52because they're quite far away
21:53from Earth's gravitational pull.
21:55But then,
21:56how does GPS navigation stay accurate?
21:59It's because scientists
22:01have figured out ways
22:02to slow those clocks down
22:03to match Earth's time.
22:05This experience with GPS clocks
22:08is a great base
22:09for what scientists
22:10need to do on the Moon.
22:11In some ways,
22:12it might be even easier
22:14than managing GPS.
22:15Scientists can work
22:16with lunar clocks
22:17as they naturally are,
22:19instead of needing to adjust them
22:20to sync perfectly with Earth.
22:22By setting up accurate lunar time
22:24from the start,
22:26scientists hope to avoid
22:27some of the complications
22:28of managing GPS satellites.
22:31And now,
22:32here's the interesting part,
22:33or maybe more interesting.
22:35To keep lunar timekeeping a reality,
22:38NASA and its partners
22:39want to set up clocks
22:40both on the lunar surface
22:41and on satellites orbiting the Moon.
22:44Some of these clocks
22:45will be long-lasting atomic clocks,
22:47and others will be
22:48crystal oscillators.
22:50Those offer stability
22:51over short time periods.
22:53Together,
22:54these clocks will create a network
22:55that scientists will be able
22:57to rely on.
22:58Meanwhile,
22:59atomic clocks for space
23:00don't come cheap.
23:02They can cost a staggering
23:03few million dollars each.
23:05Luckily,
23:06crystal oscillators
23:07are more affordable,
23:09but they don't stay accurate
23:10over long periods.
23:11Once those clocks are set up,
23:13they'll work together
23:14as part of Lunanet,
23:15which will be NASA's framework
23:17for everything related
23:18to moon-based time
23:19and data networks.
23:21Lunanet will act like
23:22an internet
23:23for lunar operations.
23:25Different space agencies
23:26will contribute to it,
23:27like how internet service providers
23:29work for us on Earth.
23:31But there's another set of challenges,
23:33and it's connected
23:34with the Moon's rotation.
23:36Firstly,
23:37a day on the Moon
23:37lasts much longer
23:39than a day on our planet,
23:40because it takes the Moon
23:41about 28 Earth days
23:43to make a full rotation.
23:45Plus,
23:45the Moon's equator
23:46experiences about
23:4714 days of sunlight,
23:49followed by 14 days of darkness,
23:51unlike Earth's regular
23:52day-night cycle.
23:54And at the Moon's
23:55south pole,
23:55where NASA is going to establish
23:57future lunar missions,
23:58there are areas that stay lit
24:00or in shadow
24:01permanently.
24:02It might make it harder
24:04for astronauts
24:04to keep track of time.
24:06NASA and its partners
24:08hope to involve
24:09more countries
24:09in this project
24:10through international organizations,
24:12like the
24:13International Astronomical Union.
24:15The idea is to get
24:16as many countries
24:17as possible on board
24:19with the lunar timescale,
24:20so that everyone
24:21exploring the Moon
24:22is on the same page.
24:24Now,
24:25another really exciting thing
24:26about all this
24:27is that figuring out lunar time
24:29could help other
24:30future space missions,
24:31like trips to Mars.
24:32The experience
24:33and knowledge
24:34we'll get from
24:35setting up a lunar timescale
24:36are likely to serve
24:37as a blueprint
24:38for managing time
24:39on even farther planets.
24:41That's one of the reasons
24:42why scientists
24:43are taking this lunar project
24:44so seriously.
24:45As for astronauts
24:47living on the Moon,
24:48a consistent,
24:49reliable time system
24:50will be essential.
24:51Not just for navigation,
24:53but for everything
24:53from scientific experiments
24:55to day-to-day activities.
24:58NASA's lunar time project
24:59is truly groundbreaking.
25:01It's the first step
25:02toward managing time
25:03as humans expand
25:05farther into space.
25:06And if they get it right,
25:08it'll mean that future astronauts
25:10won't just have
25:10Earth time to guide them.
25:12They'll also have a Moon time,
25:13and even, one day,
25:15a Mars time, too.
25:17Precise timekeeping matters,
25:18both for the sake
25:19of scientifically understanding
25:21the passage of time
25:22on the Moon
25:23and for setting up
25:24all the infrastructure
25:25necessary to carry out missions.
25:27Scientists are also eager
25:29to create a timescale
25:30from scratch
25:31because they can take
25:32everything they've learned
25:33about timekeeping on Earth
25:34and apply it
25:35to a new system
25:36on the Moon.
25:37Well, I'm out of time,
25:39so bye!
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