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Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

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Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#91

Post by philistine »

rozab wrote: post #78
perihelions wrote: post #15

This cannot be evidence of Planet 9 (the Batygin and Brown hypothesis)—it's outright incompatible with it. https://bsky.app/profile/plutokiller.com/post/3lnqm2ymbd22r If those two spots are the same object, that object is on a high-inclination orbit; but the pattern the Planet 9 hypothesis explains is only compatible with a low-inclination object.

Isn't this exactly how Pluto was discovered? Due to an innacurate estimate of the mass of Neptune (not corrected until Voyager I think), people were hunting for a large planet to explain the discrepancy. After a bunch of searching they happened to find Pluto, but it was not the Planet X they were looking for. The mass estimates for Pluto were gradually downgraded from many Earth masses to 1/500, which is the true rea…

Yeah. If Pluto had been slightly heavier, we’d probably have ended up with a definition of a planet that included its mass instead of clearing its orbit to keep Pluto a planet. But Pluto was cooked when we figured out it’s not really heavier than Ceres.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#92

Post by db48x »

juped wrote: post #9
rini17 wrote: post #5

Earlier quoted context omitted.

The same happened to Ceres first. To be fair, Make Ceres A Planet Again!

Yes, Pluto is the tenth planet. To discover Planet 9, simply open your ephemerides and look for "Neptune".

Back in the day Mercury, Venus, Earth, Ceres, Pallas, Vesta, Juno, Mars, Jupiter, Saturn, Uranus, and Neptune were the 12 planets. You could kinda consider Pluto to be the 13th planet, but in 1930 when it was discovered there were already over 1000 named asteroids. So Pluto is the 1146th planet.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#93

Post by tremon »

Qem wrote: post #84
Projectiboga wrote: post #63

Earlier quoted context omitted.

If it were earth mass it would be ~grapefruit size. This estimate puts object nine at 9 earth mass so maybe vollyball size or melon size? https://www.astronomy.com/science/is-planet-nine-a-black-hol...

If it were a blackhole it wouldn't show up in IRAS and AKARI infrared maps.

Wait, are you saying we have infrared maps showing planet 9?

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#94

Post by IAmGraydon »

tremon wrote: post #93
Qem wrote: post #84

Earlier quoted context omitted.

If it were a blackhole it wouldn't show up in IRAS and AKARI infrared maps.

Wait, are you saying we have infrared maps showing planet 9?

For god's sake man read the article before you comment.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#95

Post by mncharity »

water-data-dude wrote: post #74
1970-01-01 wrote: post #30

Earlier quoted context omitted.

Yes, also being 10x the mass of Earth that far out hints that it may be an interstellar object captured by the Sun.

I wanted to get a sense of what that MEANS relative to the rest of the gas giants. Apparently it’d be roughly the size of Uranus or Neptune. I guess I’d always put all the gas giants in the same “very, unimaginably big” bucket. I knew Jupiter was the biggest, then Saturn, but I didn’t realize just HOW big they were compared to the rest. At the risk of stating the very, very obvious, Jupiter is huge!!! Masses of gas g…

So Earth-mass orders-of-magnitude go something like: [big] 3 Juno, [balls] Ceres, Io, Moon, Mars, Earth, [gas] Uranus-Neptune, Saturn, Jupiter and super-Jupiters, [fusion] brown dwarfs, stars... .

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#96

Post by 8bitsrule »

AIPedant wrote: post #11

I think “15 times further from the Sun than Pluto” is more meaningful for most readers than “700 times further from the Sun than Earth.” If it exists, it’s way way way out there.

That IS better, but I like ~0.011Ly too ... the nearest star is about 4Ly away.

Another perspective on the size of the solar system, like the Pale Blue Dot.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#97

Post by btilly »

01HNNWZ0MV43FF wrote: post #40
libraryofbabel wrote: post #38

Earlier quoted context omitted.

The other planets formed from material in the same nebula (cloud of gas and dust) that collapsed to form the sun. The idea here is this planet would have been moving through the interstellar medium and just happened to pass close enough to the sun’s gravity well to get captured in a (very distant) orbit.

Capture would be like a reverse gravitational slingshot? This planet happened to meet the sun at an angle where it lost enough energy to fall into orbit instead of slinging back out like those comets that come around on long cycles?

It would be like a reverse gravitational slingshot, in a different way.

There is no way to capture with just 2 bodies - it would have to leave on gthe same hyperbolic orbit that it arrived on. However if it drove by and had a close enough interaction with a third body, like Jupiter, it could lose angular momentum to the planet, resulting in entering an orbit around the Sun. Further gravitational interactions with planets could then smooth that orbit out over time.

Alternately this could be the more straightforward scenario of interstellar object hits planetoid, they merge, and the new combined object is now in orbit.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#98

Post by AIPedant »

NikkiA wrote: post #70
AIPedant wrote: post #11

I think “15 times further from the Sun than Pluto” is more meaningful for most readers than “700 times further from the Sun than Earth.” If it exists, it’s way way way out there.

I dunno, '700 AU' gelled for me instantly, '15 times the distance to pluto' doesn't even make sense given pluto's orbit isn't anywhere near circular.

It makes even less sense for Earth because Earth's orbit is near-circular, whereas Planet 9's hypothesized orbit is highly eccentric, more so than Pluto.

Most people don't know off-hand that Pluto is ~40-50AU from the sun, so 700AU is hard to conceptualize.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#99

Post by bobmcnamara »

Qem wrote: post #84
Projectiboga wrote: post #63

Earlier quoted context omitted.

If it were earth mass it would be ~grapefruit size. This estimate puts object nine at 9 earth mass so maybe vollyball size or melon size? https://www.astronomy.com/science/is-planet-nine-a-black-hol...

If it were a blackhole it wouldn't show up in IRAS and AKARI infrared maps.

Would probably be a screamer on x-ray though.

Re: Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

#100

Post by mrshadowgoose »

jsbisviewtiful wrote: post #47
K0balt wrote: post #24

I hope this turns out to be wrong. I’m still holding out for a primordial back hole Planet X. That would be soooo cool and unbelievably useful.

Why useful? Considering how hard of a time astronomers are having to simply find it it’s hard to imagine it being easy to study.

A black hole in our solar system is basically "in our backyard" in relation to typical interstellar distances.

Sure, we wouldn't be able to get there for many decades, but "within a century" would be feasible.

There are so many unknowns surrounding the nature of black holes. Having one in our backyard would give us a chance to test our guesses.

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