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Light from an ionized state of helium in a distant galaxy
- didntreadarticl 4y agoIf we take the eventual heat death of the universe to be at about 10^100 years, the era we are in with stars and so on only lasts about 10^14 years. Which means light and stars and galaxies are actually just a tiny tiny blip at the start of the lifespan of the universe. Nearly all of the life of the universe will be dark with no stars, just black holes and dark distintegrating rocks and isolated particles. https://en.wikipedia.org/wiki/Future_of_an_expanding_universe#The_Stelliferous_Era https://en.wikipedia.org/wiki/Future_of_an_expanding_univers... Sweet dreams
- bjornlouser 4y ago"Nearly all of the life of the universe will be dark with no star" Maybe it will turn out that many of the double star systems were created by intelligent life
- ben_w 4y agoHow are you thinking about stars in a way that double stars will help?
- SamBam 4y agoIsaac Asimov's The Last Question is an excellent short story that explores whether future civilizations will ever be able to reverse entropy. [1] Also, Ten Chiang's Exhalation is another short story about trying to stave off the entropy-death of the universe. [2] 1. https://astronomy.org/moravian/C00-Last%20Question.pdf https://astronomy.org/moravian/C00-Last%20Question.pdf (pdf) 2. https://www.lightspeedmagazine.com/fiction/exhalation/ https://www.lightspeedmagazine.com/fiction/exhalation/
- GalenErso 4y agoI refuse to believe that the Universe isn't cyclical, because I believe the Universe has existed forever, otherwise there is no answer to the origin of everything other than something from nothing or God.
- PUSH_AX 4y agoWhy is one of those answers better than the other?
- haswell 4y agoBelieving one has a tendency to cause people to fundamentally alter how they live their lives, optimize for an afterlife at the expense of the life they actually have, and then fight wars over the belief that the afterlife is the only one that matters. As a default state of not knowing, one causes far more material harm in our current reality than the other.
- edgyquant 4y agoThis seems like your biased interpretation actually. Most people believe in God and most people don’t start wars.
- bandie91 4y agoaltough I agree with this datapoint. however the parent post's concern was not about majority, but that monotheism causes violence at all, and it causes more damage to material goods than lack of monotheism. i once disagree that monotheism, which values non-material things more than material ones, neccessarily leads to destruction of the material. orthodox Christianity for example values material and non-material, soul and body equally. secondly i disagree that this argument is valid. since if you are in the viewpoint of "all that matters is the non-material" then wasting material does not harm the world. and simirarly, supposedly saving souls at the expense of the body is incomprehensible to the materialist. so the term "harm" understood in 2 disjunct ways per the 2 frameworks. circling back to orthodoxy: it unites the "saving souls" and "saving forests" (understand well, it's not about trees, but the whole material creation clamped together in a catchphrase) attitudes in the mystery of Incarnation.
- Aperocky 4y agoThis is YOLO on the universe level.
- ye-olde-sysrq 4y ago"How can the net amount of entropy of the universe be massively decreased?"
- andai 4y agoFor the uninitiated: https://users.ece.cmu.edu/~gamvrosi/thelastq.html https://users.ece.cmu.edu/~gamvrosi/thelastq.html
- dontwearitout 4y agoThank you for sharing this!
- MichaelZuo 4y agoWhat does 'net amount of entropy' mean?
- ye-olde-sysrq 4y agoYou can already decrease entropy locally, but net for the entire universe, entropy (as far as we can tell...) always increases monotonically. And any action you take to decrease local entropy still actually increases it in total. So "The Last Question" is also basically asking - "how can we avoid the heat death of the universe?". And phrased yet again differently: "Once all the stars burn out and all the uranium is fissioned and the coal burned and the universe is just a homogenous 5 degree kelvin soup of [I'm sure some physicist could tell me whatever fundamental particle it'll be that composes this soup] - what then? Is that just it?"
- twawaaay 4y agoOnce all stars die you will be able to live very long off of the heat of dead stars as they slowly cool off to background temperature. And once those stars are completely cold, you can start converting their mass into energy by dropping them into black holes, piece by piece. And once you dropped all matter you could into black holes you could live off merging black holes. And once you merged black holes you could live off of the black hole radiation until all black holes evaporate. But this would be if the Universe wasn't expanding at a growing rate. If the Universe is truly expanding at an ever accelerating pace there will come a Big Rip which will cause every fundamental particle to get further from all other particles at speeds faster than light. And then matter as we know it will cease to exist.
- bena 4y agoThis sort of thing always fascinates me. This is all true and it absolutely does not matter. The thought of the universe sitting essentially idle for 10^86 years seems like it should feel wasteful. But why? Wasting what? Does our consciousness imbue the universe with any special quality? It's all so weird. Even some of our most fantastical science fiction only projects out a few millennia. Star Trek gets to the 31st century (or 3000s). Foundation is at least 12,000 years in the future. Dune takes place from about 23,000 to about 28,000. Warhammer 40k gets its name from the fact it takes place in the 40,000s. The Time Machine reaches to the 800,000s for the majority of its action. Red Dwarf is set the furthest at 3,000,000-ish. All of which fall way short of even 1 billion years. The Andromeda and Milky Way galaxies aren't scheduled to meet up for another 5 billion. We aren't even a blip.
- lanna 4y ago> The thought of the universe sitting essentially idle for 10^86 years 10^100 years minus 10^14 years is not 10^86 years. It is roughly 10^100 years.
- badcppdev 4y agoSmall correction to your maths but not your sentiment. 10^100 years - 10^14 years = approx. 10^100 years In the same way that: 10^6 - 10^3 = 1,000,000 - 1000 = 999,000 which is more or less approx. 10^6 Edit: Although this is one of those relatively uncommon situations where it doesn't really matter if you're off by 100 trillion years.
- bena 4y agoTrue enough. I honestly did not care enough to do anything but the most cursory attempt at math due to the scale involved. 10^14 years and 10^100 are effectively equal compared to even our entire species current lifespan.
- Taywee 4y agoYeah, it can be boiled down to "there will be stars for longer than you can fathom, then there won't be stars for longer than you can fathom". It's hard to really feel much about different timespans that are all "forever" relative to the entirety of human existence.
- thisismyswamp 4y agoThis is meaningless, nothing about those numbers matters neither does it say anything conclusive about the nature of reality. It's just our best guess right now, and we are very early.
- Aperocky 4y agoI find this interesting about human nature, that is in the want to believe in something eternal. Even if current theory about Universe is proven correct, it will most likely have no effect whatsoever on current human lifetimes. But doesn't preclude us from wanting to believe that the universe is eternal and constant, that there will be flashes of life and activity 10^50 years down the line.
- thisismyswamp 4y agoI find the reverse interesting - this anti-conventional desire to reduce scary questions to meaningless quantities in order to intellectually one up everyone else.
- didntreadarticl 4y agoTrue, there are other options https://en.wikipedia.org/wiki/Big_Crunch https://en.wikipedia.org/wiki/Big_Crunch https://en.wikipedia.org/wiki/Big_Rip https://en.wikipedia.org/wiki/Big_Rip https://en.wikipedia.org/wiki/False_vacuum_decay https://en.wikipedia.org/wiki/False_vacuum_decay etc
- __MatrixMan__ 4y agoIf this haunts your dreams, consider "The Life of the Cosmos" By Lee Smolin, as antidote. In that book he proposes that each of those black holes has a child universe associated with it, some of which have sets of physical constants that allow for grandchildren. It's a fun read.
- xwdv 4y agoFirst generation stars are so massive, couldn’t there be vast numbers of planets in habitable zones orbiting one? Seems good for a sci-fi setting with feasible interplanetary travel and trade amongst many different worlds.
- astroH 4y agoUnfortunately not. These stars have no elements heavier than hydrogen and helium so you wouldn't be able to create a rocky planet that's habitable. Furthermore their lifetimes are only 3 Myr which is much to short to form a rocky planet and also the explosion from SN if it happens or direct collapse of the star to a black hole would immediately destroy any life.
- xwdv 4y agoAh fuck, there goes that idea then I guess.
- zopa 4y agoSet it in Universe N+1 of a multiverse and mix in a tiny dusting of metals and such from Universe N. Or maybe it’s a synthetic population III star, made for unknown purposes by a now-vanished civilization. You’re allowed to make up whatever you need to get the story going.
- h2odragon 4y agointerstellar travel is so pasky, irritating and slow. A civilized culture might well cultivate such systems so that they could have a huge number of worlds in easy range of each other. Allow them those abilities and you might as well be importing already inhabited worlds from wherever you like, which saves time.
- xwdv 4y agoYea, but science fiction seems cooler when a story uses some plausible setting. In any case, another alternative is just to have a large planet with habitable moons in its orbit. Perhaps the planet itself is dead and too hostile for life, and the residents of the moons travel around it to get to civilizations on other moons.
- astroH 4y agoAs an expert in this space, I can confidently tell you that nothing about this observation is conclusive about the presence of the "First Stars" or what we call "Pop. III" Stars. By definition, the first stars are nearly completely devoid of elements heavier than hydrogen and helium. The spectra shows absolutely booming emission from Oxygen III ions at 5007A so there are heavy elements in the system and at best there is a mix of Pop III stars and more normal stars. The lifetimes of the stars are very short, ~3 Myr, so the chances of seeing them are very low which is likely the limiting factor (along with their brightness) and thus there is a strong Bayesian prior against seeing them with a narrow field of view. The mass of the system at 10^7.35 solar masses is much greater than what we expect from theoretical models that form Pop. III stars and you must ask how it's possible to not have any metals pollute the gas. The main piece of evidence for Pop III stars is HeII emission at 1640A which is a prediction of Pop. III stars, but you can also get this in many other ways, for example X-ray binaries. We see this plenty in the local Universe and we fully expect this to happen elsewhere. So to me this is headline chasing with little conclusive evidence.
- dang 4y agoThanks! I've replaced the overstated title with what seems to be a better phrase from the first paragraph. If there's a better (more accurate and neutral) title, we can change it again.
- astroH 4y agoI think this is perfect! If only we can convince the author of the article...
- omnicognate 4y agoOr the author of the headline at least. The article itself is detailed and gives most of the caveats you did.
- not2b 4y agoYes, authors of articles rarely get to choose the headline, at most, they can suggest one. The editors choose the headline and often their motivation is to maximize clicks. Ars Technica in particular sometimes uses A/B testing, randomly giving readers one of two headlines to see which one generates more clickthroughs (they've been transparent about that, there was an article describing it).
- ericmay 4y agoI know this is probably a silly question but what is the significance of locating earlier and earlier star formations versus other objects? Is it because that's what we can readily identify and improve accuracy of identifying?
- chaps 4y agoWithout those stars, we wouldn't have most of the elements we have today. But these stars no longer exist, so we have to look really far back. It's an important question!
- FreeHugs 4y agoAstronomers Say They Have Spotted the Universe’s First Stars Isn't the size of the universe potentially infinite? If that is the case, we can see only an infinite small fraction of the stars in the universe. Under that assumption, I find it hard to have a concept of what spotting the universe's first stars could mean. The oldest stars among those that we can see?
- chaps 4y agoWhat does size of the universe have to do with this? ;) The question is about the relationship between the age of the universe (well, after the big bang) and stars that came into existence afterwards. We have a pretty good idea how old the universe is, and with the universe expanding, light from the early days of the universe still makes it to earth from billions of light-years away.
- svachalek 4y agoYou could postulate that we arised from A Big Bang rather than The Big Bang, and somewhere outside the visible universe some alien species watched it happen. At least as I understand things, nothing we know about the visible universe puts any constraints, age or otherwise, on the rest of it. But for similar reasons, unless some fundamental understanding of time and space changes, nothing outside the visible universe really matters.
- ben_w 4y ago> The oldest stars among those that we can see? Yes. If I've understood the lectures correctly, time isn't really well-ordered, and on scales like this the deviation makes a substantial difference. However, what we are looking at in cases like this is stars far enough away that the light took most of the age of the universe to reach us, so it's not unreasonable to call those stars (members of the set of) "the Universe’s First Stars".
- deleted 4y ago[deleted]
- perihelions 4y agoAm I blind or does the paper not mention helium-2 at all? https://arxiv.org/abs/2212.04476 https://arxiv.org/abs/2212.04476 It talks extensively about "He II", the astrophysics notation for singly-ionized helium (a helium atom with one electron removed; He+). That isn't notation for a helium isotope. I can't see anything in the paper mentioning isotopes, nuclear reactions, or anything in that direction. (?)
- pfdietz 4y ago2He is not being observed, as it is not a bound nucleus. And this is a good thing! If 2He were bound, the pp fusion reaction would be much faster, our Sun would long since have burned out, and we would not be here.
- jonnywithoutanh 4y agoYes sorry, author here. This was my mistake and has been changed.