phys.org

TauZero, do astronomy w Black holes could come in 'perfect pairs' in an ever expanding universe

Oh! They don’t mean that black holes must come in perfect pairs! The headline makes it sound like it’s about wormholes across vast distances. No! What they’ve found is a stable “orbit” solution for the two-body problem. Normally when you place two bodies anywhere in an empty universe, they will gravitate towards each other until they collide. But in a universe with dark energy, there is some perfect distance between them, where the accelerating expansion perfectly counterbalances the accelerating attraction. They’ve used general relativity math to actually calculate such an arrangement.

The “stable” orbit in this case is the same kind of stable as a pencil balanced on its sharp tip - if it tilts even slightly one way it will fall out of control. Although they tantalize the idea that they might be able to make it truly stable against small perturbations once they finish their spinning black hole solution.

I would like to have known some specific numbers examples! Like if you have as much dark energy as our universe, and two 10-solar-masses stellar black holes, how far apart would that be? Is it like 1Ly or 1MLy? How far for two 10-million-solar masses supermassive black holes? The formulas they created should give the exact answer but I am not skilled enough to substitute the correct numbers for the letters.

elucubra, do astronomy w ESA's tiny pinhole thruster is ready for production

Nobody expects the Spanish propulsion

Gork, do astronomy w New study shows Small Magellanic Cloud is actually two smaller galaxies

Hmm. So now we should have Small Magellanic Cloud and Small Magellanic Cloud^2

outer_spec,
@outer_spec@lemmy.blahaj.zone avatar

Smaller Magellanic Cloud, and Smallest Magellanic Cloud

kalkulat, (edited ) do astronomy w Titan's 'magic islands' are likely to be honeycombed hydrocarbon icebergs, finds study
@kalkulat@lemmy.world avatar

I haven’t seen the evidence of ‘water oceans’ out there that are about more than a few water ‘geysers’ spewing from below the frozen surfaces like our breaths on winter mornings.

Whenever I hear the words ‘water’ or ‘life’ in a message from NASA I think, ‘Hmmm… who stands to gain from this PR?’ (At least telescopes return great pix and -other, visible- evidence.)

stelelor, do astronomy w Titan's 'magic islands' are likely to be honeycombed hydrocarbon icebergs, finds study

Great article, but that “summary” diagram from the original author is garbage lol

Jeredin, do astronomy w Lightest black hole or heaviest neutron star? MeerKAT uncovers a mysterious object in Milky Way

I’ve been studying the range of neutron stars for some time and I feel confident it won’t be too long until much of our evidence and observations will show that black holes, quasars, super massive black holes and the range of other black holes are very likely, more extreme neutron stars - if not quark-like stars or stellar quantum-like objects. For fun, I’ve been also been focusing on colloids, extreme condensates and their quantum/relativistic phases/states; very revealing interactions and emergent properties. Now if we could just better observe zero-point energy…

5714,

What is zero-point energy?

Jeredin,
Brunbrun6766, do astronomy w Discovery of second ultra-large structure in distant space further challenges our understanding of the universe
@Brunbrun6766@lemmy.world avatar

Doubt, something unknown? Sure. Structure? Doubt.

FishLake,

“Structure” in this case means “big glob of galaxies slightly closer together than other globs”

halcyoncmdr,
@halcyoncmdr@lemmy.world avatar

In astronomical terms structure doesn’t mean a building of any kind.

universe.nasa.gov/…/large-scale-structures/

plinky, do astronomy w Discovery of second ultra-large structure in distant space further challenges our understanding of the universe
@plinky@hexbear.net avatar

oh damn, maybe they’ll fuck up inflation again 🥳

derphurr, do astronomy w Discovery of second ultra-large structure in distant space further challenges our understanding of the universe

It’s not a “new” discovery or even the “second”. I suggest they read the 2015 paper they are almost copying from.

2015 dx.doi.org/10.1093/mnras/stv1421

Evidence suggests that this feature is the projection of a shell on to the plane of the sky. Voids and string-like formations are common outcomes of large-scale structure. However, these structures have maximum sizes of 150 Mpc, which are an order of magnitude smaller than the observed GRB ring diameter. Evidence in support of the shell interpretation requires that temporal information of the transient GRBs be included in the analysis. This ring-shaped feature is large enough to contradict the CP. The physical mechanism responsible for causing it is unknown.

Weird reporting like this is “new” GRB ring out of Swift and Sloan SDSS data.

Sloan Great Wall, which is around 1.5 billion light-years in length

South Pole Wall, which stretches 1.4 billion light-years across.

Hercules-Corona Borealis Great Wall, which is about 10 billion light-years wide

2015 en.m.wikipedia.org/wiki/Giant_GRB_Ring

It is approximately 9.1 billion light years from Earth and about 5.6 billion light years across

New objects:

Big Ring in the Sky is 9.2 billion light-years from Earth. It has a diameter of about 1.3 billion light-years

Giant Arc in the Sky which is 3.3 billion light-years across,

gravitas_deficiency, do astronomy w Japan's precision moon lander has hit its target, but it appears to be upside-down
1984, do astronomy w Japan's precision moon lander has hit its target, but it appears to be upside-down
@1984@lemmy.today avatar

Jian Yang!!

Dubiousx99, do astronomy w Japan's precision moon lander has hit its target, but it appears to be upside-down

Looks like someone missed a negative sign in the equation to account for the reverse gravity direction. /s

Fermion,
EtherWhack, do astronomy w Japan's precision moon lander has hit its target, but it appears to be upside-down
@EtherWhack@lemmy.world avatar

Looks like they forgot the C.A.T. module

FaceDeer, do astronomy w Japan's precision moon lander has hit its target, but it appears to be upside-down
@FaceDeer@kbin.social avatar
1984, do astronomy w Japan's precision moon lander has hit its target, but it appears to be upside-down
@1984@lemmy.today avatar

That earth doesn’t look flat.

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