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What if Planet 9 is a Primordial Black Hole?

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Re: What if Planet 9 is a Primordial Black Hole?

#52

Earlier quoted context omitted.

On the flip side, you wouldn't be any less dead if you fell into Jupiter and that's a lot easier to get to

Falling into Jupiter is an eye-opening experience tho, esp. if you fall into the "big eye" (pun intended). Just the sheer massive size of a turbulent, harsh planet that covers all the horizon... The world becomes flat much faster near such a planet.

We're already on a planet that covers the horizon; some say there's more beyond the horizon. Would Jupiter look subjectively bigger, if you couldn't also see the Earth for comparison?

Re: What if Planet 9 is a Primordial Black Hole?

#53
post #51

Since it's a black hole, it's gravitational effect would be at least as much as the Sun. Is there evidence to support this tug of war?

Black holes do not have more gravity per mass than any other object.

Put the other way, if the sun would suddenly change into a black hole without losing a lot of mass, the earth would still follow the exact same orbit.

Re: What if Planet 9 is a Primordial Black Hole?

#55
The interesting bit about this to me, if this is happening in our immediate neighborhood, is if it’s an indication that it’s actually a commonplace phenomenon and further - an explanation of our missing matter to bind galaxies.

A primordial black hole is not visible but it would interact gravitationally, potentially with multiple of them clustering up in groups. Dark matter work this way seemingly including clustering. Some galaxies seem to be made up by a ton of the stuff, others by barely anything. Could that be due to random chance; i.e. primordial black holes distributed unevenly since the cosmic inflation era, much like the non-uniform distribution of matter at large?

Re: What if Planet 9 is a Primordial Black Hole?

#56
post #4

Earlier quoted context omitted.

Cool, and absolutely terrifying.

Cool, and absolutely terrifying. Sibling comments are questioning this. But ... what if the black hole's orbit around the sun isn't something approximately circular? What if the orbit resembles a long-period comet? Highly elliptical? What if it puts in an appearance near the sun every 100,000 years? How would we know? What in the historical record could we study?

They have a pretty good idea of what the orbit would look like to explain the eccentric orbits of TNOs. It's not circular, but it's not that eccentric: https://en.wikipedia.org/wiki/Planet_Nine#/media/File:Planet...

Re: What if Planet 9 is a Primordial Black Hole?

#57
post #51

Since it's a black hole, it's gravitational effect would be at least as much as the Sun. Is there evidence to support this tug of war?

> While an M⊕ object is too light to be an astrophysical black hole formed by stellar collapse, PBHs arise from over densities in the early universe [15, 16] and as a result can be substantially lighter than M .

Normally black holes do have at least the mass of ~1.4 times our sun because they are formed by stellar collapse. That is why here they are considering Primordial Black Holes which a) formed differently and b) radiated some of their mass away

Re: What if Planet 9 is a Primordial Black Hole?

#59
post #14

One should not miss Figure 1 of the arXiv preprint, which is, alas, absent from the final PRL. https://arxiv.org/pdf/1909.11090.pdf It is among the rarest journal-article figures in physics. If I'd been asked to referee the paper, I'd have campaigned hard to keep it in.

My guess is that they wanted it removed since it is more useful communicating outside the field and that printing out that figure would take a lot of ink. Even if the journal doesn’t do much actual printing, I know many researchers that prefer to print out articles before reading them.

Re: What if Planet 9 is a Primordial Black Hole?

#60
post #42

Earlier quoted context omitted.

On the flip side, you wouldn't be any less dead if you fell into Jupiter and that's a lot easier to get to

Crossing into the event horizon of a black hole has a very profound poetry to it in that you will never be able to communicate back your findings. I find the romance of the destruction of knowledge very intriguing - falling into a black hole is similar to shooting a mathematician in the head in that regard. Great way to go, all things considered.

Not sure if you meant it that way but information actually can't be created or destroyed in quantum mechanics. This is known as the no-hiding theorem [1] which has been experimentally proven and which leads to the black hole information paradox. [2]

1. https://en.wikipedia.org/wiki/No-hiding_theorem

2. ttps://en.wikipedia.org/wiki/Black_hole_information_paradox

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