astronomy

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fallowseed, w Euclid reveals an Einstein ring around a nearby galaxy

‘nearby’ … speaking of relativity.

FundMECFSResearch, w Asteroid Ryugu samples suggest presence of salty water in outer solar system

Instead of an editorialised version — here is the original paper. www.nature.com/articles/s41550-024-02418-1

DemBoSain, w Asteroid Ryugu samples suggest presence of salty water in outer solar system
@DemBoSain@midwest.social avatar

Based on what we know about the universe, isn’t this pretty obvious? I’d rather see estimates for how much water?

FundMECFSResearch,

The big discovery was salty water, not water.

Zachariah, w Asteroid Ryugu samples suggest presence of salty water in outer solar system
@Zachariah@lemmy.world avatar

tears?

bahbah23,

Damn it, my head went straight to pee and yours is so much better, I got to get off the internet

southsamurai, w Moon Not as ‘Geologically Dead’ as Previously Thought, Study Reveals
@southsamurai@sh.itjust.works avatar

Okay, that’s bloody cool.

very_well_lost, (edited ) w Cosmic disturbance: The mystery of Titan's shifting orbit

The study suggests that some event within the last 350 million years altered its trajectory, preventing it from settling into a circular orbit.

That’s within the current best estimates for the age of Saturn’s ring system… maybe the same catastrophic event that formed the rings is also responsible for the anomaly in Titan’s orbit?

technohacker, w Eliminating singularities: Physicists describe the creation of black holes through pure gravity
@technohacker@programming.dev avatar

Gonna hijack this post to ask a somewhat related but possibly stupid question, would it be possible that instead of a singularity there happened to be a region of space with non-negligible size (ie, not a point sized region) that acted like a well instead? Things could “fall” into that well and not be able to escape, but it’s not like everything in the well is at a single point.

e0qdk,
@e0qdk@reddthat.com avatar

I may be misunderstanding your question, but black holes are regions of space that have non-negligible size; the boundary between what can escape and what can’t is called the event horizon. The singularity is what happens at the center.

technohacker,
@technohacker@programming.dev avatar

Ah right I worded that wrong, sorry!

I guess what I mean to say is, would a non-negligible sized “singularity” (I know I’m messing with that term quite a bit, I’ll stray from the mathematical definition) be consistent with our current theories?

BaroqueInMind,

No one can get information from beyond the event horizon, so no one can truly know besides predict with math.

Tarquinn2049, (edited )

Basically, what makes sense logically isn’t backed up by what data and math we have. Logically, we would assume as enough stuff is pulled together that the density hits a point where gravity is stronger than the bonds that hold matter together, that those bonds would break and the individual elements, initially atoms, but as gravity gets stronger and stronger the bonds between the components of atoms and so on and so forth also break down.

At some point, there is a limit to how much matter can break back down into further and further smaller components. What specifically happens when that limit is reached? That is a huge part of what could be throwing the math off. We don’t really know, but we have some guesses. Could be at the end, one of the components is weightless, and unaffected by the gravity, we do see some energy radiating out of some black holes in a straight line or “jet”. Hard to say for sure. Logic doesn’t always get us there when we don’t have enough data and need to make a leap. It might eventually, as we can slowly tie more and more stuff together with more data. Could be whatever energy starts that jet either immediately or already on the way out, mixes/mixed with other components and particles to become what we end up detecting it as. But if we could see it earlier, it maybe would be completely different before that.

gnutrino,

Depends what you mean by “our current theories”. In classical General Relatively the answer is pretty conclusively no but many people think that a quantum theory of gravity should be able to remove the singularities. In fact, this article is about an attempt to do just that with a fairly natural extension to GR (albeit one that is only mathematically tractable in 5 or more dimensions) and seems to have succeeded for the static spherically symmetric case at least.

lemming,

Nobody really thinks singularities exist. It’s only what comes out from our math. That’s also how we know our math is wrong, we’re just not sure yet how to do it better.

Sunsofold, w Two Grand Canyon-size valleys on the far side of the moon formed within 10 minutes, scientists say

Oh wow. I only have one crack in my backside.

duskfall, w Astronomers Say They Have Spotted the Universe’s First Stars

People who wanna see mee hihiii : adfoc.us/870511108889439 +18 hihi .

duskfall, w A radio transient with unusually slow periodic emission

People who wanna see mee hihiii : adfoc.us/870511108889439 +18 hihi .

duskfall, w How to Clean the Primary Mirror of a Dobsonian Telescope.

People who wanna see mee hihiii : adfoc.us/870511108889439 +18 hihi .

BlippyTheWonderSlug, w Two Grand Canyon-size valleys on the far side of the moon formed within 10 minutes, scientists say
@BlippyTheWonderSlug@ieji.de avatar

@fossilesque
It was Marvin, with a Deutonium Q-38 Space Modulator, from ACME. (obstructing his view of Venus)

shoulderoforion, w Two Grand Canyon-size valleys on the far side of the moon formed within 10 minutes, scientists say
@shoulderoforion@fedia.io avatar

that's what they want you to believe, they still haven't shown us the monolith

adam_y, w Two Grand Canyon-size valleys on the far side of the moon formed within 10 minutes, scientists say
@adam_y@lemmy.world avatar

“About 3.8 billion years ago” in case the title has you freaked.

seathru,
@seathru@lemmy.sdf.org avatar

Yeah, that was definitely some clickbait.

I would hazard to say that most major features of the moon created in the last couple billion years have done so in under 10 minutes.

maegul, w Euclid discovers a stunning Einstein ring
@maegul@lemmy.ml avatar

I’m confused about what exactly the ring is in the image or the main image at least. There seems to be an enhanced image in the article that highlights the ring more clearly as an outer edge, which makes sense (I suppose).

But I don’t understand what I’m to make of the top image. It’s the diffuse light part of the ring?

Balthazar,

You need to zoom in to the center of the bright elliptical. It would have been easier to see without zooming if they’d subtracted off the elliptical.

maegul,
@maegul@lemmy.ml avatar

Ah yes! Thanks! The enhanced image does day “close up” after all! A bit lazy of me!

Very cool though! A zoomed inset in the main image would have helped I think.

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