How Do We Know There’s a Planet 9? The Signs of Another Planet in the Distant Solar System

Are you having trouble keeping track of all the planets in the Solar System? Good news! Astronomers have found evidence that there’s another huge planet far out in the Solar System. Textbooks will need to be rewritten again. You’re welcome.

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Team: Fraser Cain - @fcain
Jason Harmer - @jasoncharmer

Created by: Fraser Cain and Jason Harmer

Edited by: Chad Weber

Music: Left Spine Down - “X-Ray”

At this point, I think the astronomy textbook publishers should just give up. They’d like to tell you how many planets there are in the Solar System, they really would. But astronomers just can’t stop discovering new worlds, and messing up the numbers.

Things were simple when there were only 6 planets. The 5 visible with the unaided eye, and the Earth, of course. Then Uranus was discovered in 1781 by William Herschel, which made it 7. Then a bunch of asteroids, like Ceres, Vesta and Pallas pushed the number into the teens until astronomers realized these were probably a whole new class of objects. Back to 7.

Then Neptune in 1846 by Urbain Le Verrier and Johann Galle, which makes 8. Then Pluto in 1930 and we have our familiar 9.

But astronomy marches onward. Eris was discovered in 2005, which caused astronomers to create a whole new classification of dwarf planet, and ultimately downgrading Pluto. Back to 8.

It seriously looked like 8 was going to be the final number, and the textbook writers could return to their computers for one last update.

Astronomers, however, had other plans. In 2014, Chad Trujillo and Scott Shepard were studying the motions of large objects in the Kuiper Belt and realized that a large planet in the outer Solar System must be messing with orbits in the region.

This was confirmed and fine tuned by other astronomers, which drew the attention of Mike Brown and Konstantin Batygin. The name Mike Brown might be familiar to you. Perhaps the name, Mike “Pluto Killer” Brown? Mike and his team were the ones who originally discovered Eris, leading to the demotion of Pluto.

Brown and Batygin were looking to find flaws in the research of Trujillo and Shepard, and they painstakingly analyzed the movement of various Kuiper Belt Objects. They found that six different objects all seem to follow a very similar elliptical orbit that points back to the same region in space.

All these worlds are inclined at a plane of about 30-degrees from pretty much everything else in the Solar System. In the words of Mike Brown, the odds of these orbits all occurring like this are about 1 in 100.

Instead of a random coincidence, Brown and Batygin think there’s a massive planet way out beyond the orbit of Pluto, about 200 times further than the distance from the Sun to the Earth. This planet would be Neptune-sized, roughly 10 times more massive than Earth.

But why haven’t they actually observed it yet? Based on their calculations, this planet should be bright enough to be visible in mid-range observatories, and definitely within the capabilities of the world’s largest telescopes, like Keck, Palomar, Gemini, and Hubble, of course.

The trick is to know precisely where to look. All of these telescopes can resolve incredibly faint objects, as long as they focus in one tiny spot. But which spot. The entire sky has a lot of tiny spots to look at.

Based on the calculations, it appears that Planet 9 is hiding in the plane of the Milky Way, camouflaged by the dense stars of the galaxy. But astronomers will be scanning the skies, and hope a survey will pick it up, anytime now.

But wait a second, does this mean that we’re all going to die? Because I read on the internet and saw some YouTube videos that this is the planet that’s going to crash into the Earth, or flip our poles, or something.

Nope, we’re safe. Like I just said, the best astronomers with the most powerful telescopes in the world and space haven’t been able to turn anything up. While the conspiracy theorists have been threatening up with certain death from Planet X for decades now - supposedly, it’ll arrive any day now.

But it won’t. Assuming it does exist, Planet 9 has been orbiting the Sun for billions of years, way way out beyond the orbit of Pluto. It’s not coming towards us, it’s not throwing objects at us, and it’s definitely not going to usher in the Age of Aquarius.

[Murked]

Should be called Erebus, as other planets are named after Greek gods. Erebus is the god of darkness and shadow

[ZzmemeguyzZ]

Since it's so difficult to find, maybe once they find it they can name it Eureka!

[wnspdns]

Planet Nine should be named Makrinos, it is Greek for 'distant', which is extremely suiting.

[incognito]

We should name Planet 9 *Theseus*, after the wise hero who grew foolish and was banished from Athens, and passed out the remainder of his days in exile.

[jtiss_]

''Gravity's silhouette remains, but the planet, disappeared it has.'' ''Go to the center of gravity's pull, and find your planet you will''

[anon]

Call it 'Martha' so everyone will stop fighting each other

[sclair]

Call it Hades, because then you get the poetic thing where "Pluto" was a planet all along.

That or George

[DecibleRhymez]

Nox: Goddess of night. Since planet nine is so far from our sun, it's basically in eternal night

[agp]

Call it Festivus, I am sure it would be fun to have a big party there.

[alfiegalpinmusic]

I don't care what anyone says, Pluto will always be a planet in my heart. #plutostillaplanet

[jeffmathers]

Terminus: a God who protects borders and boundary markers. An apt name if ever there was one.

[DecibleRhymez]

Janus: God of Beginnings, Endings, Transition, Doorways and Keys

[EcstasyTiger]

Planet Nine should be named Nemesis, after the hypothesised Nemesis star that was blamed for periodic space related mass extinctions :)

[orvoshorizonfire]

Planeton, and make it a pokemon. That'll get millions of people looking for it.😁

[Eric_D_]

Planety McPlanet face


serious answers: Erebus, Hades, Thor, etc.

[ausgepicht]

This video rocks. What a fantastic job of making this easy to understand and presenting it in an interesting way as opposed to the typically dull fashion of presentation whereby people either fall asleep listening or are lost with the technical jargon. Well done. Subscribed.

[dur]

We should call it Nox. Goddess of the Night and Darkness. Starts with N like Nine

[shivainvalidos]

We should call the planet Janus, because it's the beginning of our understanding of an entire solar system as one star system of many. Endings of looking at objects that are just circling around our own navel. Transition to be better at exploring the outer heliosphere. Doorway to discover extra solar objects, and key to explore how safe it is to send something to another star system.

[dm_nimbus]

Polyphemus, because it's herding all those other objects

[Jonathan-xeec]

What if the Planet nine is not a planet, but a very small sized black hole? Which is why despite of all the implications, we are not able to find it....?