astronomy

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MachineFab812, w The Orion You Can Almost See

That link changes daily, so for now I’mma just have to link to this thread.

Still, holy shit.

BradleyUffner, w Scientists found a primordial galaxy with a bunch of gas and no stars

How is this different from a nebula?

makyo,

Seems like you could call this a galaxy-sized nebula

AmosBurton_ThatGuy, (edited )
@AmosBurton_ThatGuy@lemmy.ca avatar

From my amateur understanding of space, it seems to be a galaxy made of just primordial hydrogen and helium, back before the first stars formed and started creating heavier elements due to the fusion reactions that power stars and the eventual supernovas that further dispersed and helped to create even more heavy elements.

Another cool theory is that the first stars are thought to have been much, much more massive, possibly up to around a thousand solar masses since they were made solely of hydrogen and helium. It’s estimated that current stars couldn’t get above a few hundred solar masses at most due to the existence of heavier elements in modern gas clouds. I don’t understand enough to explain why the existence of heavier elements limits star size so I’ll leave that to someone smarter than me.

Someone correct me if I got anything wrong, again I only have an amateur level of understanding about space.

XeroxCool,

I think the heavier elements exponentially speed up stellar death. In part, the fusion of elements makes the core denser and denser each step of the way. Going from hydrogen to helium is twice as dense, but helium is still a good fuel so it isn’t an issue. As fusion continues through carbon and oxygen, it shrinks but still burns. Iron is the tipping point though because it doesn’t work as a fuel at all - it triggers a core collapse, the surface falls into the void, and everything heavier than iron is instantaneously fused and thrown into the universe.

So I would guess the lesser abundance of heavier elements early on delayed that process compared to today’s standards. Sort of like making a snowman in fresh powder and having to melt/wet the snow to make it pack vs having a little rain and higher temps after the powder to wet it

AmosBurton_ThatGuy,
@AmosBurton_ThatGuy@lemmy.ca avatar

Thanks for the explanation! :)

rbhfd,

The amount of heavy elements present in a star when it formed will be neglible to the amount that will be created over time through fusion.

You can actually detect this through spectroscopy because the initial amount of metals will be present in the outer layer of the star. Heavy elements made through fusion will be mostly in the core.

The reason stars formed from primordial gas, i.e. only consisting of hydrogen and helium, is that such a gas will fragment less as it cools and collapses. Less fragmentation means heavier stars.

I only have a high level knowledge of the process though.

verity_kindle, w Astrobotic's Peregrine lander suffers propulsion issue, making moon landing unlikely
@verity_kindle@lemmy.world avatar

That’s frustrating. Anyways, SpaceX! Turnaround record of 3 hours! Something fails, learn from it and launch another one. The ULA invests so much money and time, it makes every mechanical or propulsion failure seem catastrophic.

Valmond,

It might be cheaper but it’s not like its free you know.

jadero, w Total solar eclipse 2024: Live updates

I’m more interested in the magical appearance of four states in “southeast” Canada than yet another solar eclipse.

Did someone forget to vet the AI’s output?

hperrin, w The Phases of Venus

Fun fact: Venus and Mercury wouldn’t have phases if the earth were flat and the sun were small and close.

(At least, they wouldn’t have a “new” phase.)

asg101, w After all of This Time Searching for Aliens, is it The Zoo Hypothesis or Nothing?

My theory is that if any ETI exists, our species is under quarantine until we have either grown up or burned ourselves out. They will have seen violent, self-destructive beings in the past and know it is dangerous to let them spread and destroy peaceful society. If they can travel between the stars, they would have to be able to communicate to keep cohesion, this communication could very well include the warning “Avoid this system, there are killer apes on that planet”.

Spacehooks,

Or avoid the vampires, werewolves, and zombies that are constantly around based on the intercepted documentaries.

asg101,

Well the vampires are on the nightly news reports about Wall Street, and zombies are shown in attendance at every tRump rally… so yeah the ETs would certainly know they are quite prevalent here. Don’t see as many werewolves in the news, but they interview a shit ton of ghouls.

stelelor, 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

Thorned_Rose, w Neptune and Uranus seen in true colours for first time
@Thorned_Rose@kbin.social avatar

Bit of a misleading title - not for the first time, but rather seen accurately again.

DriftingDeep, w Neptune and Uranus seen in true colours for first time

InB4 “Uranus seen in true colors for first time.”

Really though, I don’t know why it never crossed my mind that the picture of Neptune was so… saturated. It’ll take a little bit to reconcile this new perspective of a “light bluish-green” Neptune. It’s just so jarring to alter a belief held since my childhood.

clearedtoland, w Neptune and Uranus seen in true colours for first time

First they take away Pluto and now they’ve come for Neptune! My childhood was a lie.

Xariphon, w A Bizarre State of Matter Exists Deep Inside Large Neutron Stars

Would it be a yes-or-no thing, or more of a continuum?

At stellar mass x there's Some quark soup but it's mostly ordinary neutronium, at 50x there's More, at 10,000x there's Pretty Much All Of It, etc?

Or is it a critical mass kind of thing where at stellar mass x there's No Soup For You and at x+3 it's a veritable soup buffet?

MartianSands,

The latter, I suspect. That’s certainly how forming a neutron star works in the first place, because if a star gets so dense that it can form neutronium then the neutronium (which is far more dense than the core was before) can easily keep making more.

It’s a similar story with black holes. Get past the threshold at which it forms, and the process runs away and swallows the whole star.

If a quark soup is more dense than neutronium, then it would be fairly all-or-nothing

Gork, 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

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

Nobody expects the Spanish propulsion

Vqhm, w Should Astronauts Be Allowed to Eat Each Other If They’re Starving?

Wouldn’t be the first time and prolly won’t be the last time.

Jamestown.

Jamestowne is home to the ruins of the first permanent English settlement in North America.

104 settlers but only 38 survived

Despite writing describing cannibalism:

“Haveinge fedd upon our horses and other beastes as longe as they Lasted, we weare gladd to make shifte with vermin as doggs Catts, Ratts and myce…as to eate Bootes shoes or any other leather,” he wrote. “And now famin beginneinge to Looke gastely and pale in every face, thatt notheinge was Spared to mainteyne Lyfe and to doe those things which seame incredible, as to digge upp deade corpes outt of graves and to eate them. And some have Licked upp the Bloode which hathe fallen from their weake fellowes.”

Direct evidence of cannibalism at Jamestown, the oldest permanent English colony in the Americas was elusive until recently finding “bones in a trash pit, all cut and chopped up, it’s clear that this body was dismembered for consumption.”

smithsonianmag.com/…/starving-settlers-in-jamesto…

LibsEatPoop, w Should Astronauts Be Allowed to Eat Each Other If They’re Starving?

This is freaking hilarious. I might buy this book just to read more of this:

“Imagine you’re stranded on the Red Planet with three crewmembers,” Seedhouse, a professor at Daytona Beach’s Embry-Riddle Aeronautical University wrote. “You have plenty of life-support consumables but only sufficient food to last one person until the rescue party arrives. What do you do?.. One day, while brewing coffee for breakfast, you realize there are three chunks of protein-packed meat living right next to you.”

… the biggest of the Mars explorers should sacrifice themselves first because they “both consume and provide the most food.” He went on to provide a “weirdly detailed look” at how to cut up one’s fellow humans if necessary.

“We don’t know where Seedhouse would fall in the buffet line because we couldn’t find his height and weight online,” the authors wrote, “and honestly we’re scared to ask.”

In “Survival and Sacrifice”… readers will also find… a photo of ten astronauts smiling in space alongside the caption: “In the wrong circumstances, a spacecraft is a platform full of hungry people surrounded by temptation. Is it wrong to waste such a neatly packaged meal?”

Great marketing.

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