phys.org

Zaktor, do astronomy w Saturn's largest moon most likely uninhabitable

It feels like the title should be “uninhabited”. Life on earth doesn’t survive because we continue to be bombarded with nutrient carrying asteroids, it just needed them to kick it off. That few nutrients are likely to make it from the surface to the ocean means the genesis is unlikely to occur, but it doesn’t seem to make a decision about whether an unlikely genesis could survive, even if only in a small pocket of the ocean.

Balthazar, do astronomy w An astronomer's lament: Satellite megaconstellations are ruining space exploration

Starlink is causing problems, but it seems to me that this image was made in bad faith to oversell the case. The caption says it’s a combination of 29 separate exposures, but if those exposures were combined properly, you wouldn’t see the satellites (median combination does wonders, and there are more sophisticated techniques which do even better). Some streaks start at one chip edge and extend to another chip edge, without continuity across the focal plane. So it’s not at all clear just how this image was created. And why on earth is it not flat-fielded? Maybe this is just really sloppy image processing, but even amateurs can do far better than this, leaving the final combination with no satellites at all.

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

zerozaku, do astronomy w Earth bids farewell to its temporary 'mini moon' that is possibly a chunk of our actual moon

What?! Nobody told me that we got a new moon.

acockworkorange,

We literally did, you just weren’t paying attention. That should teach you!

Murdoc, do astronomy w Huge star explosion to appear in sky in once-in-a-lifetime event

I wonder if there’s a way to get an alert or something so I don’t miss it. I tried searching for one but so far no luck.

Tiltinyall, do astronomy w Huge star explosion to appear in sky in once-in-a-lifetime event

The last reoccurrence was after 80 years in 1946, I wonder why they are expecting it 2 years early?

Annoyed_Crabby,

They did said “80 years or so” and “around 80 years”, maybe they did their calculation and predicted that this year is likely the time that it happen. They did give a huge margin of when it will happen though.

0v0,

According to Wikipedia:

In March or April 2023, it dimmed to magnitude 12.3. A similar dimming occurred in the year before the 1946 outburst, indicating that it will likely erupt between April and September 2024.

Pronell, (edited ) do astronomy w A NASA mission that collided with an asteroid didn't just leave a dent. It reshaped the space rock

Neat. Makes sense. An asteroid isn’t usually one chunk of rock but several chunks conglomerated.

You think you might break it up but you rearrange it instead.

At least that’s how my dumb ass read it.

JoMomma, do astronomy w An astronomer's lament: Satellite megaconstellations are ruining space exploration

You can just say Starlink, it’s the only one

apfelwoiSchoppen,
@apfelwoiSchoppen@lemmy.world avatar

Amazon is planning and implementing the same.

Zachariah, do astronomy 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

technohacker, do astronomy 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.

BaroqueInMind, do astronomy w Astronomers discover an ultra-massive grand-design spiral galaxy

Putting on my sci-fi hat; a distant galaxy that is likely a billion years older than ours, very likely has had enough time to develop life somewhere in the trillions of stars that formed within it, by the time the photons of that galaxy finally reached us and hit that very specific telescope sensor at that very specific moment the JWT engineers were observing.

foofiepie, do astronomy w Astronomers discover biggest ever seen black hole jets, which blast hot plasma well beyond their own host galaxy

Ok. Permission to ask a mad question. Apologies in advance.

If black holes ‘suck’ everything in… could there be the equivalent of the ‘other side’ of one, that’s mysteriously ejecting a tonne of plasma?

Not saying that’s what this is, just prompted the thought.

imakeninjascry,

Mathematically, it’s possible, but scientists are still skeptical about whether or not they are real. They’re called white holes and you can actually create a model of one in your kitchen sink. If you let the water just hit the bottom and spread out evenly in all directions, you can kind of visualize the way it’s supposed to work. Action Lab on YouTube actually has a pretty good video about it which I suggest watching if you’re interested. youtu.be/p3P4iKb24Ng?si=b3_RHuj0J3F_7DC1

chuckleslord,

Tangent, but you don’t need to include the question mark or anything after in most urls. Definitely not YouTube links. It’s just YouTube telling itself who shared the info (you) and they use that to track shit. But the link works just as well without it, and you’re not voluntary spying on yourself.

imakeninjascry,

Neat! I didn’t know that. I just copied and pasted. Thanks for the info.

kamenlady, do astronomy w Earth to have new mini-moon for two months
@kamenlady@lemmy.world avatar

Completely out of context, but your username always reminds me of one of my faves nigelthreetimes

Mbourgon, do astronomy w Huge star explosion to appear in sky in once-in-a-lifetime event

I love that “recurrent nova” is a phrase.

XeroxCool,

Novas can recur. Supernovas cannot

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