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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?

#31

Post by ThatCaio »

onlyrealcuzzo wrote: post #23
Konohamaru wrote: post #7

Earlier quoted context omitted.

This is not scary. Yes the event horizon will expand the more matter falls into its gravity well, but otherwise a black hole acts like a normal planet orbiting the Sun.

Is there a theoretical limit on the minimum mass of a black hole? It's counter-intuitive to me that something could get dense enough to form a black hole and not have more mass than the Sun, or at least enough mass to steal Pluto.

Yes, Tolman–Oppenheimer–Volkoff limit would estimate a star around 1.5-2.5 sun masses could result in a stellar black hole.

We don't know much about stars collapsing, and the mass wasted in the process to have a more accurate number at this point.

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

#32

Post by hadlock »

onlyrealcuzzo wrote: post #23
Konohamaru wrote: post #7

Earlier quoted context omitted.

This is not scary. Yes the event horizon will expand the more matter falls into its gravity well, but otherwise a black hole acts like a normal planet orbiting the Sun.

Is there a theoretical limit on the minimum mass of a black hole? It's counter-intuitive to me that something could get dense enough to form a black hole and not have more mass than the Sun, or at least enough mass to steal Pluto.

Ted Kazinski was concerned that high energy particle physics would create a blackhole large enough to become self sustaining. If I remember correctly, high energy physics creates tiny black holes during particle collisions, but they "evaporate" faster than they can absorb mass.

So to answer your question with my limited understanding, yes, there's a lower limit to stable black holes. Beyond the critical mass, they simply evaporate in a matter of seconds.

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

#33

Post by NamTaf »

ISL wrote: 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.

I love it. I found it actually useful to get a physical scale understanding of the size of one.

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

#34

Post by kzrdude »

deepspace wrote: post #8
127 wrote: post #4

Earlier quoted context omitted.

Cool, and absolutely terrifying.

Agree with cool, but not with terrifying. According to the paper, the mass would be ~5-15 M⊕ at a distance of 300-1000AU, so not a threatening object in any way.

I assume M-plus means Mass of earth?

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

#35

Post by NamTaf »

kzrdude wrote: post #34
deepspace wrote: post #8

Earlier quoted context omitted.

Agree with cool, but not with terrifying. According to the paper, the mass would be ~5-15 M⊕ at a distance of 300-1000AU, so not a threatening object in any way.

I assume M-plus means Mass of earth?

Yes. Similarly, M with a dot in the circle is the sun.

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

#36

Post by behnamoh »

wlesieutre wrote: post #5
127 wrote: post #4

Earlier quoted context omitted.

Cool, and absolutely terrifying.

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.

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

#39

Post by PhantomGremlin »

127 wrote: post #4
wrnr wrote: post #3

A person should be allowed to dream sometimes, how freaking cool would this be. A block hole right in our neighbourhood, even closer than Alpha Centauri. Just imagine what kind of things can be learned from studying it.

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?

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

#40

Post by canjobear »

themodelplumber wrote: post #17
ISL wrote: 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.

Fascinating. And kind of funny. I wonder, are there any YouTubers who walk through the math in papers like this? Asking because it seems really interesting and sometimes it's fun to learn bits here and there from applied math rather than always working up from the fundamentals.

PBS SpaceTime
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