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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?

#101

Post by Recurecur »

lmilcin wrote: post #98
pas wrote: post #93

Earlier quoted context omitted.

What does that do? I mean you can walk in 1G just fine, so probably we could go there, take a walk/sit there in 1.6G, and leave, right? That means that if we put a 100km wide structure around it, we can service it easily(?) even without robots.

I can't imagine we will be building things like that manually. By the time a swarm of robots will process blueprints and take raw materials and construct the structure semi-autonomously or even completely autonomously. The structure would most certainly not admit human presence. It only has to redirect radiation to where it is useful (maybe send a starship on a laser beam, for example).

Maybe ships will need laser power . It remains to be seen if near-C travel is at all feasible, due to radiation/erosion from impacting interstellar material. If not, a ship can easily carry its own fuel, it will just be a generation/hibernation ship.

Or, perhaps our extropian descendants won't care about travel time. ;-)

OR, maybe the black hole could power a hyperspace portal or something equally exotic...

Regardless, having a compact object nearby to play with would be fun!

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

#102

Post by jbotz »

This paper has been on Arxiv since nearly a year ago; surprisingly it apparently didn't make HN at the time, even though it did get a bit of publicity then, including the MIT technology review[0]. Despite the sense of humor evident in the included to-scale "picture" of a black hole, the paper is quite serious... it may be speculative, but it's science. Also, the authors are not the first to speculate that the OGLE microlensing events could be best explained by a population of primordal black holes[1]. However, Planet 9 could still just easily just be an ordinary planet.. the final point of the paper is that we should look for both, the two requiring different search strategies.

Anyway, no matter how plausible or implausible, this post made my day. A mini black hole, close enough that we could send a probe there? How cool is that?!

[0] https://www.technologyreview.com/2019/09/30/410/is-planet-9-...

[1] https://arxiv.org/abs/1901.07120

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

#103

Post by T-A »

jbotz wrote: post #102

This paper has been on Arxiv since nearly a year ago; surprisingly it apparently didn't make HN at the time, even though it did get a bit of publicity then, including the MIT technology review[0]. Despite the sense of humor evident in the included to-scale "picture" of a black hole, the paper is quite serious... it may be speculative, but it's science. Also, the authors are not the first to speculate that the OGLE mi…

> This paper has been on Arxiv since nearly a year ago; surprisingly it apparently didn't make HN at the time

https://news.ycombinator.com/item?id=21078068

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

#104

Post by Recurecur »

Recurecur wrote: post #100
pas wrote: post #93

Earlier quoted context omitted.

What does that do? I mean you can walk in 1G just fine, so probably we could go there, take a walk/sit there in 1.6G, and leave, right? That means that if we put a 100km wide structure around it, we can service it easily(?) even without robots.

It's not that, it's the difference in the gravity field between two points. On Earth, the gravity field is very close to uniform. Near a small black hole, the field changes rapidly and is very strong. It's a "pull" effect, meaning that if you were oriented with your feet towards the object as described by the GP, and 2m tall, your feet would experience 1.6 G more "gravity" than your head. It's a tidal force, literall…

BTW, regarding "standing" in this gravity field...

If there were a structure to stand on, rather than you being in orbit, the force of gravity would be about 160 billion times the force of gravity on Earth (~1,594,000,000,000 m/s^2).

That's for a 10,000,000 Earth mass black hole at 50 km.

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

#105

Post by Recurecur »

Recurecur wrote: post #100
pas wrote: post #93

Earlier quoted context omitted.

What does that do? I mean you can walk in 1G just fine, so probably we could go there, take a walk/sit there in 1.6G, and leave, right? That means that if we put a 100km wide structure around it, we can service it easily(?) even without robots.

It's not that, it's the difference in the gravity field between two points. On Earth, the gravity field is very close to uniform. Near a small black hole, the field changes rapidly and is very strong. It's a "pull" effect, meaning that if you were oriented with your feet towards the object as described by the GP, and 2m tall, your feet would experience 1.6 G more "gravity" than your head. It's a tidal force, literall…

So, I just calculated the orbital speed at 50 km. It came out to 282,378 km/s. The speed of light is 299,792.5 km/s, so we're way into relativistic territory.

Good luck having enough energy to build a structure around it! ha

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

#106

Post by lovemenot »

Recurecur wrote: post #104
Recurecur wrote: post #100

Earlier quoted context omitted.

It's not that, it's the difference in the gravity field between two points. On Earth, the gravity field is very close to uniform. Near a small black hole, the field changes rapidly and is very strong. It's a "pull" effect, meaning that if you were oriented with your feet towards the object as described by the GP, and 2m tall, your feet would experience 1.6 G more "gravity" than your head. It's a tidal force, literall…

BTW, regarding "standing" in this gravity field... If there were a structure to stand on, rather than you being in orbit, the force of gravity would be about 160 billion times the force of gravity on Earth (~1,594,000,000,000 m/s^2). That's for a 10,000,000 Earth mass black hole at 50 km.

If Planet 9 were indeed a black hole its significance would surely be that prevalence of lower mass black holes is orders of magnitude more common than currently known.

This particular one may not be practical for energy generation, but it would be obviously worth looking for others of more useable mass.

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

#107

Post by shifto »

me_me_me wrote: post #99
canjobear wrote: post #40

Earlier quoted context omitted.

PBS SpaceTime

Half of their stuff goes over my head. And I have to watch videos multiple times, but very interesting channel indeed.

This channel makes me feel dumb. It all goes over my head but he is explaining it like he is teaching a group of 10 year olds.

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

#108

Post by rishav_sharan »

We know that most heavy elements in the solar system come from a supernova explosion. I have always thought that the 9th "planet" was the remnant of this explosion and that this dead was the ancient binary companion of sun.

But yeah. Just fanciful thoughts here and no evidence, or even, good arguments to back it up. :)

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

#109

Post by dogma1138 »

Recurecur wrote: post #101
lmilcin wrote: post #98

Earlier quoted context omitted.

I can't imagine we will be building things like that manually. By the time a swarm of robots will process blueprints and take raw materials and construct the structure semi-autonomously or even completely autonomously. The structure would most certainly not admit human presence. It only has to redirect radiation to where it is useful (maybe send a starship on a laser beam, for example).

Maybe ships will need laser power . It remains to be seen if near-C travel is at all feasible, due to radiation/erosion from impacting interstellar material. If not, a ship can easily carry its own fuel, it will just be a generation/hibernation ship. Or, perhaps our extropian descendants won't care about travel time. ;-) OR, maybe the black hole could power a hyperspace portal or something equally exotic... Regardles…

One thing will have to change if we ever can travel at relativistic speeds or have function cryogenics (or anything similar) will be markets and investments, just think of putting even a relatively small amount into a yielding investment even an index fund and going to “sleep” for 200 years not only would you get immediately to benefit from 200 years of advancement but you’ll also get to benefit form 200 years of what effectively is compound interest.

I really wonder what will the societal implications of such a path being possible are going to be.

There are plenty of people that will be willing to push a pause button right now to be able to wake up in a world where you could buy a ticket to mars, add to that the quite likely possibility of becoming a millionaire if not a billionaire if you put enough money into any inflation beating investment and you get quite the incentives package.

Sure you might never wake up because the world is going to end in a nuclear holocaust or your icebox will experience a kernel panic 17 years into your suspended animation but overall this quite likely be a much lower possibility than dying prematurely today.

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

#110

Post by cercatrova »

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.

> The associated DM halo however extends to the stripping radius ∼8AU, this would imply a DM halo which extends roughly the distance from Earth to Saturn (both in real life and relative to the image).

Well, how can the article authors know we're reading this on Earth and not some other planet?

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