00:00Have you heard about Planet 9?
00:03No, not Pluto.
00:05We're talking about something lurking
00:07on the outskirts of the solar system.
00:10A mysterious planet that exists in our solar system
00:13that we haven't yet discovered.
00:16We've been looking for it for years.
00:19But finally, it seems like scientists found
00:22a key to solve this mystery.
00:25Planet 9 is a hypothetical planet.
00:28Astronomers have been on the hunt for it
00:30for quite some time now.
00:32But it's so elusive
00:34that they've only been able to piece together
00:36a few details about its potential characteristics.
00:40One thing we do know
00:42is that Planet 9 has to be a massive world.
00:45Possibly up to 10 times the mass of Earth.
00:49That's one big planet.
00:51It's also thought to be a distant wanderer
00:54hanging out somewhere between Neptune and Pluto.
00:58Some scientists think that Planet 9
01:00might actually be a mini-Neptune
01:03with a thick, gaseous atmosphere
01:05and a rocky core.
01:07Others speculate that it could be an icy world
01:10with a solid, frozen surface
01:13and a thick layer of hydrogen and helium gas.
01:17Of course, since we haven't actually found Planet 9 yet,
01:21we can't say for sure what it's like.
01:24We're not even sure that it even exists.
01:27Some say it's just a myth,
01:29like the Tooth Fairy or the Easter Bunny.
01:31But others are convinced that it's out there somewhere.
01:35And at the end of the day,
01:37we're not entirely sure if Planet 9 is even a planet.
01:40It might be a special kind of black hole
01:43or made entirely of dark matter.
01:46The search for Planet 9 began in the early 21st century
01:50when a group of astronomers realized
01:52that something wasn't quite right
01:54with the outer reaches of our solar system.
01:57They noticed that some distant objects,
02:00known as trans-Neptunian objects,
02:02were behaving in unexpected ways.
02:05Trans-Neptunian objects, or TNOs,
02:08are like the cosmic version of those items
02:11in the back of your fridge that you forgot about for years.
02:14They're small, icy bodies
02:16that hang out in the Kuiper Belt,
02:18beyond Neptune.
02:20So, scientists noticed
02:22that these guys started behaving weirdly.
02:25At first, they thought it might be a fluke.
02:28But as they dug deeper,
02:30they began to suspect
02:32that there was a ninth planet lurking out there.
02:35Why haven't we discovered it yet, you ask?
02:38Well, it may be because of Planet 9's weird orbit.
02:42All the other eight planets orbit the Sun
02:45in roughly the same plane,
02:47which is like a flat disk.
02:49However, our hypothetical friend's orbit is different.
02:53It might be tilted
02:55and move in a different direction
02:57compared to the other planets.
02:59Its orbit might also be stretched out like an oval,
03:02rather than being nearly circular like usual.
03:05Because of this,
03:07Planet 9 might spend most of its time
03:10far from the Sun, like a true introvert.
03:13It only comes relatively close to the inner solar system
03:16every few thousand years.
03:18This would make it super faint
03:20and hard to spot.
03:22So the only way we may discover it
03:24is by studying the gravitational effect
03:26it has on our solar system.
03:30And this isn't the first time
03:32astronomers have gone looking for a new planet.
03:34Back in the 19th century,
03:36there was a similar hunt
03:38for a hypothetical Planet X.
03:40But this time,
03:42they were armed with much better technology
03:44and a much better sense of humor.
03:46They began calling their elusive quarry
03:48Planet 9,
03:50which was much catchier than Planet X.
03:52They even came up with a hashtag
03:54for the search,
03:56Pluto Lives.
03:58It was a reference to the fact
04:00that Pluto had been kicked from the planet gang
04:02and some astronomers were eager to find
04:04a new planet to take its place.
04:06But the search for Planet 9
04:08has been no easy task.
04:10It's like trying to find a lost sock
04:12in the laundry basket
04:14the size of a football stadium.
04:16It's so far away
04:18and so faint
04:20that even the most powerful telescopes
04:22can't see it.
04:24Instead, astronomers have had to rely
04:26on indirect evidence,
04:28like the strange orbits of TNOs,
04:30to try to figure out
04:32where it might be.
04:34Some scientists have even supposed
04:36that it might be a wandering rogue planet,
04:38which would explain
04:40why it's so hard to find.
04:42But they haven't given up hope.
04:44Till this day,
04:46they're scouring the skies
04:48using all sorts of high-tech telescopes
04:50and fancy algorithms
04:52to try and spot this elusive planet.
04:54And fear not,
04:56dear curious human,
04:58because it looks like after so many years
05:00of research,
05:02we may have finally found the key
05:04to solve this mystery.
05:06Astronomer Man Ho Chan
05:08has a theory.
05:10He believes that Planet 9
05:12could have a bevy of moons.
05:14That's right.
05:16Not only is it a giant planet
05:18hiding out in the depths of space,
05:20but it's also a bit of a hoarder.
05:22Moons are all the rage
05:24in the outer solar system.
05:26In fact, almost every planet here
05:28has at least one moon,
05:30except for Mercury and Venus.
05:32Earth has just one,
05:34which is kind of sad if you think about it.
05:36Non-planetary bodies like Pluto
05:38have at least a couple of moons.
05:40A bit unfair, isn't it?
05:42Anyway, taking this into account,
05:44let's go moon picking with Planet 9.
05:46The region between
05:48the rock-filled Kuiper Belt
05:50and the rock-filled Oort Cloud,
05:52where this planet is predicted to be,
05:54should be ripe for the picking.
05:56Chan made some calculations
05:58and determined that it would be stranger
06:00if the elusive planet didn't have
06:02any satellites.
06:04According to his calculations,
06:06an object the mass of Planet 9
06:08should capture at least 20 TNOs
06:10as large as almost
06:1290 miles across.
06:14It's like our mysterious planet
06:16is playing cosmic Pokemon with these guys.
06:18So, what if Planet 9
06:20has moons?
06:22Would that make any difference?
06:24Kinda, yes.
06:26They could give us some indirect clues
06:28to finally locate this mysterious planet.
06:30Now, you might be thinking,
06:32how in the cosmos
06:34can we possibly spot these teeny tiny moons?
06:36It's not like they're going
06:38to wave a giant flag
06:40or blast some Beyonce tunes to get our attention.
06:42Well, apparently,
06:44the key lies in something called
06:46tidal heating.
06:48Tidal heating might sound like
06:50a new workout trend,
06:52but it's a real scientific phenomenon.
06:54It happens when two celestial bodies
06:56are close together.
06:58You see, tides aren't just about
07:00the rise and fall of the ocean,
07:02they're also the result of gravity
07:04pulling unevenly on a planet or moon.
07:06When a planet and a moon
07:08are close enough to each other,
07:10their gravity pulls on each other,
07:12creating a bit of a football shape.
07:14And as these celestial bodies
07:16move around each other,
07:18they shift shape and generate friction inside,
07:20which produces heat.
07:24Wow, who knew that Planet 9
07:26could have a workout routine?
07:28Perhaps we should start calling it
07:30Gym Planet instead.
07:32Anyway,
07:34if Planet 9 has any moons,
07:36the gravitational pull from these moons
07:38would cause it to change shape constantly,
07:40generating heat in the process.
07:42And we might be able
07:44to detect this mysterious planet
07:46through the heat produced by those moons,
07:48even though it gives off
07:50no other signals.
07:52Now, before you get too excited,
07:54finding them won't be a walk in the park.
07:56They're incredibly small
07:58and would be very far away from us.
08:00But hey, nothing worth discovering
08:02ever came easy, right?
08:04Scientists are optimistic
08:06that with the right technology,
08:08they can spot this telltale sign.
08:10It will be easier for us
08:12to spot them with fancy instruments
08:14like modern telescopes.
08:16Talk about cool friends to have, right?
08:18Sure, the process of finding it
08:20may be difficult and time-consuming,
08:22but the potential payoff
08:24is huge.
08:26Finding this planet could explain
08:28a lot of the strange behavior observed
08:30in TNOs, the Kuiper Belt,
08:32and beyond.
08:34As we've already mentioned,
08:36they've been acting super weird lately,
08:38tilting and aligning in suspicious ways.
08:40If this planet doesn't
08:42actually exist,
08:44we have yet to explain
08:46what is the reason for this strange behavior.
08:48In any case,
08:50the search for Planet 9
08:52is one of the most exciting and intriguing quests
08:54in modern astronomy.
08:56It's like a cosmic scavenger hunt,
08:58and everyone's invited to join in on the fun.
09:00So, grab your telescopes
09:02and let's go planet hunting.
09:04Who knows, maybe we'll find it
09:06sooner than we think.
09:08That's it for today.
09:10So hey, if you pacified your curiosity,
09:12then give the video a like
09:14and share it with your friends.
09:16Or if you want more, just click on these videos
09:18and stay on the Bright Side!
