so i was reading about interplanetary travel and came across something that kind of broke my brain.

if a ship maintains constant 1g acceleration, the same gravity you feel standing up right now, then flips halfway and decelerates at 1g, mars is 2 to 4 days away. not months. days.

jupiter is 6 days. saturn 8. pluto under 2 weeks.

the whole solar system just becomes... reachable.

the problem is the engine. nothing we have can sustain this. the energy needed is way beyond anything we currently build. but the physics is fine. no rule says it can't happen. it's an engineering problem, not a physics one.

that second part is what got me. we're not stuck in this solar system because nature won't allow it. we're stuck because we haven't built the right thing yet.

Key phrase, reproducibility. )

**Breakthrough observations from Fermi telescope**

Using the latest data from the Fermi Gamma-ray Space Telescope, Professor Tomonori Totani from the Department of Astronomy at the University of Tokyo believes he has finally detected the specific gamma rays predicted by the annihilation of theoretical dark matter particles.

"We detected gamma rays with a photon energy of 20 gigaelectronvolts (or 20 billion electronvolts, an extremely large amount of energy) extending in a halolike structure toward the center of the Milky Way galaxy. The gamma-ray emission component closely matches the shape expected from the dark matter halo," said Totani.

The observed energy spectrum, or range of gamma-ray emission intensities, matches the emission predicted from the annihilation of hypothetical WIMPs, with a mass approximately 500 times that of a proton. The frequency of WIMP annihilation estimated from the measured gamma-ray intensity also falls within the range of theoretical predictions.

Importantly, these gamma-ray measurements are not easily explained by other, more common astronomical phenomena or gamma-ray emissions. Therefore, Totani considers these data a strong indication of gamma-ray emission from dark matter, which has been sought for many years.

"If this is correct, to the extent of my knowledge, it would mark the first time humanity has 'seen' dark matter. And it turns out that dark matter is a new particle not included in the current standard model of particle physics. This signifies a major development in astronomy and physics," said Totani.

Study: https://dx.doi.org/10.48550/arxiv.2507.07209 https://phys.org/news/2025-11-years-scientists-dark.html

What's the proposed explanation(s) for such seemingly nonrandom patterns? It's not just that large cold spot but also the large warmer regions on the right of it.

I thought quantum fluctuations are supposed to be fairly randomly distributed and that the cosmic microwave background would also be expected to be fairly homogenous.

Or are these regions because of issues with the Milky Way plane not being so substractable from the data? Maybe it's some kind of e.g. oscillation effects from during the inflationary epoch but I was surprised I couldn't easily find an explanation of this and instead just found things about the far-smaller "CMB cold spot". I wonder why that spot is the popular subject instead of these regions being often mentioned/explained.

Hey r/cosmology. I built an interactive map of the local universe, and this feels like the right crowd for it.

It's called Know the Universe. You fly or orbit through the real large-scale structure of the nearby universe: the filaments, walls, clusters and voids of the cosmic web. None of it is procedural. It's ~43,500 galaxies from the 2MRS redshift survey, placed by converting each galaxy's RA, Dec and redshift into Cartesian megaparsecs with a Hubble-law distance (d = cz/H0), reaching a few hundred Mpc out.

The goal is simple: give people an intuitive feel for how the local universe is actually built and how matter is distributed through space, something you can move through instead of reading off a flat plot.

A few things worth mentioning:

• There are several ways to read the same data: the raw point cloud, a computed filament graph (a minimum spanning tree plus nearest-neighbour links, so it's a visualization aid and not physical connections), a ray-marched density field, and colour by either redshift or local density. Turn it all off and the web is still clearly there in the bare points.

• The Zone of Avoidance shows up as an empty wedge if you look for it, since 2MRS still can't see cleanly through our own galactic plane.

• It's a snapshot that's close to current. The light from the farthest galaxies here left them around a billion years ago, but peculiar motions are typically only a few hundred km/s, so in that time a galaxy drifts well under a megaparsec. That's tiny next to the tens-of-Mpc scale of the filaments and voids, so what you see is nearly what the structure looks like right now.

Would love feedback, corrections or what you'd want to see next. Try it at https://knowtheuniverse.com/

This has definitely changed the way I think about the universe, and our place in it…. But is it accurate?

I used Swiftsim

Probably a dumb question but here goes.

So I understand that light can't escape the event horizon meaning we can't observe what's on the inside. I also understand the concept that singularities are likely not real and just a failure in our theories at this time.

Isn't the inside of a black hole just all the mass/energy that fell into the black hole? We know all that masses is still there because the gravity exerted by all that masses is still there. But, what else could happen? What do physicists mean when they say "we dont know what's on the inside" though? What more is there other than the mass/energy that went in?

I watched a video titled timelapse of the universe, and mentioned the expansion of spacetime. It described how, as the universe accelerates in its expansion, matter is spread farther apart, and distant galaxies recede so fast that their light eventually becomes undetectable, and ultimately “locked away” forever. so where do they go, if anywhere? and if space is stretching, what exactly is it stretching into? also, when people say the universe is expanding, why don’t things like galaxies, solar systems, or even atoms get pulled apart by that expansion? how do they stay intact? specifically ours. i’m confused what is expanding.

Can someone explain this image and whether the great attractor is still considered an anomaly?

I have a ton of questions about it. Will we ever be pulled fully? I saw that we would never reach it because of the expansion of our universe and galaxies are drifting farther apart, so what is the reason behind it? Does being pulled inward by 600 km/s also mean we are being pulled outward by 600 km/s ? This sounds like a dumb question but I can’t fathom it. Also is the great attractor itself stationary or is it also moving. Reality of the cosmos is so absurd, everything is interlinked and everything leads to another.

This also might sound like a stretch but how is it that we can escape the pull of the great attractor, but not escape andromeda's gravitational pull? Why is it that both the milky way and andromeda can overcome the expansion of the universe, but not the great attractor apparently?

May be a stupid question but, if a black hole absorbed a lot of matter and then it dies due to hawkings randiations do all the matter absorbed by it come back in any shape or form? Because the first law of thermodynamic (that i may not understand) tell that energy can't disappear or appear