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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

#41

Post by api »

nonethewiser wrote: post #33
api wrote: post #21

Earlier quoted context omitted.

They're not dangerous unless you get too close. A black hole is not a cosmic vacuum cleaner. If the Moon were suddenly transformed into a tiny black hole with the same mass, it would continue to orbit the Earth at the same distance. Ocean tides due to its gravity would continue normally. There would not be much effect except that it would no longer be visible with the naked eye and would no longer reflect the sun's l…

That is very interesting and made me realize I did think of black holes as “sucking” things in. Which I see is not the right way to think about it.

It’s an object with theoretical maximum density. That’s one way to think about it.

Another visualization: if you had an Earth mass black hole with a solid shell surrounding it at the same radius as the Earth’s surface is from its core, gravity atop that shell would be 1g. The actual black hole would be about the size of a marble.

If you got close to it you would of course be subject to insane gravity and be “spaghettified” etc. All the mass would be in that marble. But at a distance it would be the same.

Compared to that object the Earth is mostly empty space. Ordinary matter is not that dense.

Black holes are totally fascinating. They are in some ways the most extreme objects that can possibly exist. If we could study one we could learn a lot.

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

#42

Post by kiba »

api wrote: post #7
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…

I really hope this is true, because it would mean there is a black hole close enough it could be examined and studied. This might allow us to test physics ideas that can’t be tested any other way, and maybe even to “finish” physics. It could also allow gravity and Oberth effect acceleration of small probes to meaningful fractions of the speed of light for interstellar flyby missions. Imagine the Oberth effect boost f…

We could use the black hole to power our civilization due to how efficient it is for generating power.

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

#43

Post by oxidant »

ck2 wrote: post #25
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.

There's an episode on "Space & Beyond" where they show all the planets in scale to the realworld on an actual football field. Then to show Planet 9 distance they have to get in a car and drive a few miles. That worked for me.

I think Bill Nye has something similar, too.

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

#44

Post by irrational »

gus_massa wrote: post #18
metalman wrote: post #3

we already have a 9'th planet, but due to the greatest pedantic campain of all time, pluto got demoted. Though given the current situation, ha!, that could change.....perhaps the naming commity will get noticed, and be offered a chance to do a deal, and Make Pluto A Planet Again,(MPAPA)

If you add Pluto, you must add also Eris and a few more, like 5 or more, and perhaps also Ceres. Here is a nice graphic that excludes Ceres https://en.m.wikipedia.org/wiki/Dwarf_planet#Population_of_d...

I would add those to the list of official planets, yes. Don’t remove Pluto, add the rest.

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

#45

Post by api »

kiba wrote: post #42
api wrote: post #7

Earlier quoted context omitted.

I really hope this is true, because it would mean there is a black hole close enough it could be examined and studied. This might allow us to test physics ideas that can’t be tested any other way, and maybe even to “finish” physics. It could also allow gravity and Oberth effect acceleration of small probes to meaningful fractions of the speed of light for interstellar flyby missions. Imagine the Oberth effect boost f…

We could use the black hole to power our civilization due to how efficient it is for generating power.

Not at that distance but black hole starship drives are theoretically possible. Far, far beyond our capabilities but possible within known physics. This is like Kardashev type II civilization stuff.

Domesticating fusion would be much easier. That is within sight.

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

#46

Post by philipov »

api wrote: post #41
nonethewiser wrote: post #33

Earlier quoted context omitted.

That is very interesting and made me realize I did think of black holes as “sucking” things in. Which I see is not the right way to think about it.

It’s an object with theoretical maximum density. That’s one way to think about it. Another visualization: if you had an Earth mass black hole with a solid shell surrounding it at the same radius as the Earth’s surface is from its core, gravity atop that shell would be 1g. The actual black hole would be about the size of a marble. If you got close to it you would of course be subject to insane gravity and be “spaghett…

That's Newton's Shell Theorem for you.

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

#47

Post by jsbisviewtiful »

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.

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

#48

Post by swayvil »

tliltocatl wrote: post #35
nonethewiser wrote: post #32

Earlier quoted context omitted.

Forgive my ignorance but how is that different than the rest of the planets?

The rest of the planets are theorized to have condensed from the protoplanetary disk that formed the same molecular cloud the Sun did. I. e. they have formed at approximately same time as the sun and from same material, sans gravitational separation.

Ah, so a captured body would be quite different and alien. Really old too. Like, first generation of stars.

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

#49

Post by tough »

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?

gravitational capture

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

#50

Post by marcosdumay »

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?

AFAIK, it could be in a 2 bodies slingshot, multi-body interaction with some other stuff on the Oort cloud, or tidal interaction (what could happen way more easily with a nebula).
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