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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

#131

Post by userulluipeste »

tiahura wrote: post #113

How can we spot planets in other galaxies when we can’t even be certain how many planets are in our solar system?

It has everything to do with the available means that we have, for now. For the record though, we haven't yet been able to spot planets in other galaxies, just in our own Milky Way. The spotted ones just happened to be there when we decided to look, twice. To spot an astral body properly sized to fit the definition of planet, which we yet suspect to orbit around our own star, we should be lucky enough to look exactly at it and not at something else.

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

#132

Post by AIPedant »

zamadatix wrote: post #126
AIPedant wrote: post #98

Earlier quoted context omitted.

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.

They're all horrible to conceptualize because people don't commonly deal with how far even something like the Earth to the Sun is, I don't think there is any winning answer here - at least an AU is consistently defined and maybe slightly more likely to be familiar, but it's still just about as crap to be honest. Side note: Apart from AU already being defined as average distance and not current distance, the distance…

My point was not about intuiting the distance, it's about what the solar system looks like qualitatively, as a cartoon with orbits drawn around the sun. Most people have no idea if 700AU is closer than Pluto, a little further than Pluto, or much further than Pluto. 15x the distance of Pluto is much more direct.

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

#133

Post by Dylan16807 »

Projectiboga wrote: post #63
randomtoast wrote: post #6

I find one theory regarding Planet 9 especially interesting, and that is that it could be a primordial black hole with a Schwarzschild radius on the order of just a few centimeters. So basically, just a golf ball-sized black hole. This would explain why we can see the gravitational effects on the other objects as described in many papers, and it would also explain at the same time why we have no direct observation of…

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...

Grapefruit versus volleyball? If you make a black hole 9x as heavy, it gets 9x the radius. 700x the volume.

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

#134

Post by Waterluvian »

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.

On its own it’s a bit of a useless number. You’d have to know how many AU Pluto is to understand context.

But if you got “15x further than Pluto” you have context without needing to know any other trivia-style numbers.

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

#135

Post by vpribish »

I can clearly see the object as a bright group of pixels in the IRAS image, but I don't see a damn thing at the spot they hilight in the AKARI image. Like, are they kidding or is this a crap article with the wrong image or something?

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

#136

Post by carbocation »

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.

All 3 points (two from you and one from '8bitsrule) helped me contextualize this:

* 700 times further from the Sun than the Earth

* 15 times further from the Sun than Pluto

* 0.01 lightyear, or 1/400th the distance to the nearest star

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

#137

Post by zamadatix »

AIPedant wrote: post #132
zamadatix wrote: post #126

Earlier quoted context omitted.

They're all horrible to conceptualize because people don't commonly deal with how far even something like the Earth to the Sun is, I don't think there is any winning answer here - at least an AU is consistently defined and maybe slightly more likely to be familiar, but it's still just about as crap to be honest. Side note: Apart from AU already being defined as average distance and not current distance, the distance…

My point was not about intuiting the distance, it's about what the solar system looks like qualitatively, as a cartoon with orbits drawn around the sun. Most people have no idea if 700AU is closer than Pluto, a little further than Pluto, or much further than Pluto. 15x the distance of Pluto is much more direct.

What's the benefit of communicating something is 15x the distance of Pluto if people are expected to have at least a ~15x error in how far away Pluto is supposed to be? At that point it's all nonsense, nothing is relevant anymore. Might as well say something useful for those who do have a clue about the solar system.

Hell, it's been nearly 2 decades since Pluto was itself planet 9. Just bringing the name up in a discussion about planets is going to cause more confusion.

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

#138

Post by setr »

zamadatix wrote: post #137
AIPedant wrote: post #132

Earlier quoted context omitted.

My point was not about intuiting the distance, it's about what the solar system looks like qualitatively, as a cartoon with orbits drawn around the sun. Most people have no idea if 700AU is closer than Pluto, a little further than Pluto, or much further than Pluto. 15x the distance of Pluto is much more direct.

What's the benefit of communicating something is 15x the distance of Pluto if people are expected to have at least a ~15x error in how far away Pluto is supposed to be? At that point it's all nonsense, nothing is relevant anymore. Might as well say something useful for those who do have a clue about the solar system. Hell, it's been nearly 2 decades since Pluto was itself planet 9. Just bringing the name up in a disc…

15 time further than the furthest once-planet is fairly intuitive to say really freaking far; you don’t need to know how far pluto is, just that it’s the furthest.

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

#139

Post by bobmcnamara »

XorNot wrote: post #112
bobmcnamara wrote: post #99

Earlier quoted context omitted.

Would probably be a screamer on x-ray though.

Not without an accretion disk, and why would it have one? It would've cleared it's orbit.

Hawking radiation does not require an accretion disk.

Edit: with an accretion disk, I'd assume we'd have noticed it by now. Outside of that, as a black hole gets smaller, the hawking radiation wavelength should go down. It is rather weak overall, but it would be rather close. I haven't actually done the math, and, this is not my area of expertise. Would a relatively close by small black hole's hawking radiation be brighter than further X-ray emitters? Dunno.

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

#140

Post by [deleted] »

shiandow wrote: post #53
TheOtherHobbes wrote: post #16

Earlier quoted context omitted.

I really hope it isn't true because if there's one out there, there will be others, and I'd rather not meet one in person. We don't have enough data to see whether there are unexpected instabilities in detected planetary systems. But it would be an interesting project to look for those.

Running into a rogue black hole must be far less likely than an extinction level impact with a relstively boring big rock.

[deleted]
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