I thought I heard once that our universe could be a holographic projection on a 2D plane surrounding around a black hole.
Don’t ask me for any details further than that, because I do not remember.
Comment on sweet dreams
lost_tortie@lemmy.world 5 months ago
Or that the observable universe could be inside of a black hole. Don’t watch too many black hole videos before bed.
Planet 9 is not a primordial black hole and it can’t hurt you. 🙀
kakes@sh.itjust.works 5 months ago
quilan@lemmy.world 5 months ago
There was an episode of PBS Space Time on the holographic principle in general recently, and I believe they’ve also discussed the black hole thing as well.
HawlSera@lemm.ee 5 months ago
Projected by what?
kakes@sh.itjust.works 5 months ago
I don’t remember.
rikudou@lemmings.world 5 months ago
If it’s a block hole, it doesn’t really matter. A black hole is not more dangerous than a planet with the same mass, it has the same gravity. The only difference is that it’s much tinier. If planet 9 is a black hole, it’s so small that Sun has stronger gravity (and bigger mass), meaning it’s bound to rotate around the Sun the same way every other large body in the Solar system is.
Planet 9 maybe is or isn’t a primordial black hole and it won’t hurt you.
MotoAsh@lemmy.world 5 months ago
IIRC, isn’t it closer to a white hole, what with expansion? If you were far enough away, you cannot reach ‘there’ vs being guaranteed to reach ‘there’ like a black hole. Though really, it’s neither. Just curved spacetime.
The fact we think of white holes and black holes as separate entities just goes to show our great lack of understanding of spacetime.
EtherWhack@lemmy.world 5 months ago
My understanding is its similar in difference to a protostar and a nova
Slotos@feddit.nl 5 months ago
I mean, Schwarzschild radius shows that for a medium of constant density (and on a large scale, Universe is fairly uniform) there is an upper limit of a radius of a ball comprised of said medium above which it will form an event horizon.
en.wikipedia.org/wiki/Schwarzschild_radius#Calcul…
Which means that an infinite universe of non-zero density is either a bloody paradox (spend a minute deciding where exactly event horizons should form), or our understanding of gravity and spacetime breaks on ginormous scales just as it does on micro ones.
Transporter_Room_3@startrek.website 5 months ago
From my understanding of primordial black holes, if one were so close as to be in our solar system, it is very small.
Since it’s so small, it would have fizzled out through hawking radiation output a long time ago.
So yes, planet 9 is NOT a black hole that can hurt you.
Now, a pocket of warped spacetime that will one day spawn a Chaos Demon? Maybe.
HawlSera@lemm.ee 5 months ago
It still fucks with me that we went from 9 planets to 8, pour one out for Pluto
Transporter_Room_3@startrek.website 5 months ago
Well at one time people “knew” that space was filled with Aether, and people knew that the universe was no more than 2 million years old.
But once you understand things more, some of the things you know turn out to be wrong.
In this case it’s more like “we called this thing a planet before we knew just how tiny it really is but it’s still cool so we now have categories for things just like it”
Which I think is neat.
You can be sad it’s not a planet, we can also be happy that it pulled one over on all of humanity for such a long time.
ilinamorato@lemmy.world 5 months ago
There are SO MANY Men In Black references in this thread and NOBODY is pointing them out and it is driving me CRAZY
Semjaza@lemmynsfw.com 5 months ago
Pour one out for Ceres, for being downmoted so long ago people forget it was a planet.
Pour one out for Makemake and Hamuhea, for being discovered so recently they never got to be planets.
Swedneck@discuss.tchncs.de 5 months ago
the only thing that changed is what we call it, pluto has existed since before humans and will continue to exist after humans most likely, and it does not give even the tiniest shit about what we call it.
“planet” is an arbitrary category that mostly just exists because we like to put things into categories, much like the concept of a continent.
It’s just really difficult to say that pluto is a planet if we want to have any sort of vague definition for what a planet is, because pluto is more similar to a ton of objects in the solar system than it is to the other bodies we very confidently refer to as planets.
If nothing else you have to also call ceres a planet if you include pluto, and how many people give a shit about ceres?
0ops@lemm.ee 5 months ago
That’s messed up