eli5: Is the possible existence of a 9th planet actually back on the table now? If so, what did we find out?

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I’ve heard about this a few times recently, at first I chalked it up to the old, but viral “Planet X or Planet 9 discovered” hoax that’s been made on multiple occasions, but there’s a variety of recent articles pointing to the possibility. I am aware that such news brings a lot of trafic (so money) to news outlets, so I was wondering if this was simple sensationalist news or something we’re actually proposing again?

I definitely remember learning about how unlikely it was for a **real** planet beyond the orbit of Neptune to exist. (Fairly) Modern calculations and observations were also pointing towards it not even being a possibility.

So what changed in the last year? What have we learnt, observed, discovered, calculated, etc.? Is this misinformation or an actual old scientific hypothesis that’s being reinvestigated again in light of recent and new data?

(Possibly used the wrong flair, but it kinda made sense.)

In: Physics

8 Answers

Anonymous 0 Comments

“Planet 9” has been proposed as a way to explain the orbital behavior of certain objects outside the orbit of Neptune. Such a planet has not been actually observed, and there are alternate explanations for the observed behavior of objects.

Anonymous 0 Comments

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Anonymous 0 Comments

A 9th planet for our solar system has been a running theory for a long time. It’s a common solution for inconsistencies in the orbits of the planets. Outside of orbital variations and some associated math there is so far no proof of it. In other words we have yet to find a planet where it’s supposed to be.

The Orbital behavior of Neptune and objects beyond Neptune are the key evidence, there is something tugging on them.

There are alternative explanations for what could be doing this, but that hasn’t stopped astronomers from doing the math to try to locate such a planet.

Candidates include a tiny red dwarf star on a very distant orbit, meaning that the Sun would actually be a binary. It’s just so dim, and the orbit so long that we haven’t detected it yet.

The more common theory is that our solar system used to have at least 1 more gas giant and it was ejected onto a distant and very elliptical orbit.

Early computer models of the solar system seem to work better when there’s at least 1 more gas giant (and possibly several rocky super earths). It’s orbit would have been disturbed when Jupiter and Saturn migrated away from the Sun to their current distance causing this gas giant to be ejected.

It’s also theorized that it passes through our solar system on a regular basis (relatively speaking) and its disruption of the Kuiper Belt is what causes regular periods asteroid/comet bombardment.

This is all educated speculation though, eventually they’ll discover what’s causing the orbital fluctuations of Neptune and beyond. If it’s a 9th planet cool! if not, also cool!

Anonymous 0 Comments

“Planet Nine” is a hypothetical planet proposed to exist by legit astronomers Mike Brown and Konstantin Batygin to explain the way the orbits of certain transneptunian objects appear to be arranged. You can see conferences and presentations of them on YouTube, they’re very good at stating their case. However, until they find it (and they’re searching for it, but it’s not an easy task at all), it’s just a hypothesis. Nothing’s changed in the last year with regards to their search.

“Planet X” was a planet proposed to exist by astronomer Percival Lowell at the beginning of the 20th century, to explain certain perturbations believed to be observed in the orbit of Neptune. The search for Planet X eventually led to the discovery of Pluto, but none of Lowell’s predictions turned out to be true (basically, Pluto isn’t nearly massive enough to perturb Neptune’s orbit). The “perturbations” in the orbit of Neptune turned out to be just innacurate observations from back in the day. When the Voyager spacecraft flew by Neptune and we got more accurate data, the “perturbations” vanished. So it’s safe to say that Planet X never existed and that the discovery of Pluto was just a lucky coincidence.

Any news in he media (and specially if it’s not a specialized and reputable source, like, say “Sky & Telescope” or “Nature”) regarding this subjects is probably just click-baity material you shouldn’t waste your time on.

Anonymous 0 Comments

A paper out recently ran a new simulation which showed the pertubations in (I think Neptunes) orbit can only be explained by the existence of a 9th planet. The paper is unverified or peer reviewed yet.

Anonymous 0 Comments

A number of objects could be seen, and they implied there would be counterbalancing objects. So the call went out to look and instead other objects were found.

Basically, telescopes find what is in the light right now. That changes over time. Eons of time. So by looking hard, not so obvious stuff was found where the first call to look was.

The big kicker is infrared telescopes, including now available jwst, should be able to see any close planetary thing. The bigger the planet, the brighter it gets in infrared. So theres a cap on how big a thing could hide through this search.

Then recently, the growing list of new small objects have implied a new pattern.

So what the modern news really amounts to is that there’s a new hot patch of sky to look at. It’s probably light conditions have changed a little. Stuff out there moves very slow. No promises on what they find, but any informed clue helps narrow the sky. They haven’t been finding planets, but they are finding stuff.

Anonymous 0 Comments

Isn’t the ninth planet Pluto?

Anonymous 0 Comments

Wouldn’t it be crazy if Zechariah Sitchin was right?