For those replying to this article with "imagine living there", please note that if life is a verdant, resilient and common as many of us hope it is, the universe might contain quite a number of insane places to live:
- Near the center of a galaxy, where stars are so closely packed together that the night sky is filled with bright lights, perhaps illuminating their world to what we experience around twilight, or even brighter.
- Far removed from the center of a galaxy, or even on a rogue star that has escaped its galaxy early on. Very few stars visible in the sky.
- Inside a 'thick' nebula, obscuring all other entities in the sky except for their own star and planets. Imagine an interstellar object like Oumuamua passing through and the complete perplexity of a civilization observing it and wondering where it could have come from.
- A double planet system.
- A system where the planet's orbit is highly elliptic, or where the precession of a tidally locked planet causes day/night cycles.
> Inside a 'thick' nebula, obscuring all other entities in the sky except for their own star and planets. Imagine an interstellar object like Oumuamua passing through and the complete perplexity of a civilization observing it and wondering where it could have come from.
This is almost the exact premise of Life, the Universe and Everything, the third book in the Hitchhiker's Guide to the Galaxy series.
Thickness (or rather its optical depth) of this nebula would be wavelength dependent - in IR you could see through all the distant stars, while in all other wavelength, including X-rays, that nebula would glow.
> Near the center of a galaxy, where stars are so closely packed together that the night sky is filled with bright lights, perhaps illuminating their world to what we experience around twilight, or even brighter.
My understanding is this is unfavorable for life due to any planets being constantly sanitized by too many nearby stars going supernova
> Far removed from the center of a galaxy, or even on a rogue star that has escaped its galaxy early on. Very few stars visible in the sky.
My understanding is this is also unlikely since a total lack of nearby stars would deprive a star system of the heavier elements needed to make molecules out of anything more interesting than helium and hydrogen.
It’s possible that a happy medium between too many or few is needed for life (or at least highly favored along a bell curve along which our conditions are more likely to be near the top)
There's plenty of chemosynthetic life on earth that doesn't need a sun - even if earth style life needed the sun to evolve, if the earth became a rogue planet those organisms might be fine. And life might not have needed the sun to evolve.
Yeah, that doesn't work when you're not receiving any heat whatsoever. There needs to be an energy input. For Earth, that's the sun. Where is the energy coming from otherwise?
> Inside a 'thick' nebula, obscuring all other entities in the sky except for their own star and planets.
Similarly to the alien planet in Eric Flint's "Mother of Demons"; there was a permanent thick cloud cover, and the the slowly moving sky illumination due to the unseen sun was called "the mother of pearl" by the locals.
I also like the idea of living in a dense globular cluster. Interstellar probes and, later, manned missions would be feasible quite early into civilization's technological development - since you're just a few light-weeks (or less) from another star, not a few light-years like us.
I thought the consensus was that stars in globular clusters are exceedingly unlikely to host planets, since they'd be ejected by the frequent interactions with other stars.
> Therefore, it is still possible that planets exist around main sequence stars in globular clusters, although at small numbers because of the low metallicity, and at orbital periods of >~10 days.
What would it be like for civilization to have evolved on a world with a moon (or other large natural satellite) in geosynchronous orbit. There’s just this … thing, in the sky, hovering over one spot. How sacred would that spot be to those people
Good one. The novel Courtship Rite by Donald Kingsbury had such a moon (the Scowlmoon) as part of the worldbuilding.
For another, imagine having a moon so big it can completely cover the sun... and just the right size and distance to only block the photosphere, leaving the corona visible without instruments. What a show that'd be, what wild myths the life there might make up.
- Active galaxy with a jet stretching perpendicularly to the galaxy plane for distances much bigger than the galaxy's size, shinning in all the wavelengths.
- Planet around a double star one of which is a black hole or a neutron star.
Planet around a double star one of which is a black hole or a neutron star
I'm not sure that would be very habitable. Unless they're far apart, the neutron star/black hole would be accreting matter from its companion and the accretion disk would be emitting large amounts of x-rays. In some cases, they can occasionally increase in luminosity by a factor of 10, emitting powerful bursts of x-rays.
I believe anywhere near a neutron star is going to be extremely inhospitable. A very compact massive object, spinning really fast, and with a strong magnetic field, will produce intense synchrotron radiation, right?
Wikipedia says the magnetic field of a neutron star is between 10^8 and 10^15 times the Earth's. The amount of energy in a magnetic field that strong is mind-boggling. Anything anywhere near a neutron star will be bathed in intense broadband radiation, and whipped about by a rapidly-rotating magnetic field. Not a nice place to set up camp.
I'd imagine something like the Anarres/Urras double planet system described by Ursula K Le Guin in The Dispossessed (one of my favourite novels) - https://en.wikipedia.org/wiki/The_Dispossessed
> Inside a 'thick' nebula, obscuring all other entities in the sky except for their own star and planets. Imagine an interstellar object like Oumuamua passing through and the complete perplexity of a civilization observing it and wondering where it could have come from.
You'd be able to peer through the nebula with higher frequency bands than visible light, no?
If a civilisation is able to notice an interstellar object like ’Oumuamua, they are probably advanced enough to observe what's outside their nebula.
But without a long history of looking up at the stars with our own eyes, how would we ever have thought to point radio telescopes up there?
There might be interesting phenomena going on right now that we don't know about just because they're too far awar from what our natural senses can detect.
A multi-star system where at least one star is almost always in the sky. They'd never see other stars, and their estimate for how many stars exist would be wildly off. And if there ever were a moment where all suns set together, they'd be overwhelmed. (There's a scifi story like this, I think it might have been from asimov, but I'm not sure)
That equation is just a back of the envelope guess, not a proven law. We have a sample size of 1 so we can make no generalizations about the trillions of star systems in the universe.
I get incredibly frustrated with popular science articles that use only artist’s impressions and avoid the real images.
To me, the real images are much more exciting. You don’t need fake clarity and fake colour when you’re seeing a (candidate) high speed black hole sucking the life out of some fricking ginormous balls of flaming nuclear fusion.
This article is even worse, that it shows an illustration without a caption identifying it as an illustration, which is very misleading. (Later they show it again with the caption saying it's an illustration.)
NASA used that image, but the first words under it were "this is an artist's impression of..." which is the right way to label things if you don't want people mistaking an illustration for real data.
The figures in the primary literature are great for scientists and reasonably educated adults, but they're trying to capture the imaginations of children and those not so scientifically literate.
It's understandable. If you show the actual figures to a layman, many of them would respond in disbelief or disappointment. You have to build a bridge, and that begins with illustration. It's a communication and education tool.
I disagree. By only showing the artist’s impression they give a false sense of what our scientific capabilities are. The images are amazing but they’re also rather poor in the mind of a child who only ever sees artist’s impressions and 4K HDR Marvel movies of things hurtling through space.
This means that the aren’t being exposed to reality and how we can use such noisy low resolution images to make important discoveries. They are lead to believe that there is no advancement that they can potentially follow a career to achieve. The work is done and they shouldn’t aspire to make science better.
The JWST has been an excellent example of what can be achieved by showing the damn images.
Then use both. Many science 'educators' do a terrible job of dumbing things down so much that kids who want to pursue their interest farther get filtered when they hit the scholarly literature unless they are lucky enough to have imaginative teachers.
> Then use both. Many science 'educators' do a terrible job of dumbing things down so much that kids who want to pursue their interest farther get filtered when they hit the scholarly literature unless they are lucky enough to have imaginative teachers.
Exactly… I never understood the point of making science more accessible to the masses, if the compromise was making the actual science inaccessible to the inquiring mind. There’s no reason there can’t be a simple abstract followed by the actual science and associated images / maths.
Agreed, especially for the headline image of “captured an image of” articles. Artists’ impressions are fine but don’t sell them click bait style as genuine.
Not sure what the deal is with this hubblesite.org…
Edit: Ah ok, interesting… It’s entirely legit. The “about us” page says the website is produced by the Space Telescope Science Institute (https://www.stsci.edu).
Yeah, STScI is very legitimate (I work there as an astronomer) and it has an excellent Office of Public Outreach team.
The graphic does specify that it is an illustration, but I agree that it could explicitly mention that it's an artist's rendition of the (authors' physical interpretation) of the astronomical observations.
Incredibly cool. That is an absolutely massive structure, twice the length our Milky Way is across. Those images are like no astronomy images I've ever seen.
If you lived on a planet going around one of those stars it sure would be hard to make sense of the universe.
"Oh I have it! In addition to all the incomprehensible things in the universe, we happen to live in a star system that is extremely, extremely rare and exeptional, unlike the rest of the universe!"
Asimov's Nightfall tells the story of the beings living on a planet surrounded by 6 suns. The sky is always bright with at least a sun over head. They've only known the universe consisted of bright sky and the 6 suns for centuries. On a rare eclipse event where all the suns are hidden, they are suddenly in darkness and looking into billions of stars at the night sky.
There actually is a sextuple star system in the night sky.
Castor looks like a single star but actually consists of three binary stars: two of them in a binary system that is itself in a binary system with the other binary star.
I don't know if there could be a stable position for a planet that would never experience nights, but there is at least some reason behind the idea.
Isaac Asimov is a science fiction author (a good one, too), but the work he created was not a real description of our universe -- it was fiction, and playing with ideas.
You can imagine the pivotal moment here, where someone (according to Wikipedia, it was Immanuel Kant, which is a neat fact all by itself) said "hey, that band of faint stars could be a gravitationally rotating disk seen from the inside, and what if those other oblong smudges we see are entire other disks really really far away?"
For residents of our hypothetical planet, that moment, which seems very important to me, would be hard to have!
I don't think that's true either. I think it was just the first such to get translated to English. I think it's popular because the premise is interesting. The Dark Forest is just part of the vocabulary now, and that's not an accident, it's genuinely worth thinking about and, if not technically new, at least newly popularized.
On a "technicality" front, I'm sure you could find something if you dug through the archives, but really there was no hard modern scifi in China that was heavily published and got any traction until TBP. The party even discouraged fantasy media. I lived there and hung out with nerds, and they were ecstatic when the book came out.
Did you read the wiki link? There's very little, and much of it is more kafka-esque political commentary rather than hard scifi.
I don't know, I lived in China for 9 years, and scifi and fantasy media were highly discouraged by the party (as mentioned in the wiki link), and no one I knew had anything to recommend that was originally written in Chinese. When Three Body Problem came out, people went nuts. Every nerd and engineer in the country read it.
Thank you. It’s amazing that +1bn people with theoretical access to the world’s resources didn’t spontaneously create 10000 sci-fi books. Similar isolation the other way around. Societies are still so isolated (language, culture, political leanings) despite so much integration.
Did you read all three? The first one isn't great but as a trilogy I found it quite good. There are several places where the story building contradicts itself but if you are willing to look past those then it's solid science fiction. It's not on the level of Arthur C. Clarke or Asimov but they were obviosly big influences.
No. I was ready to give up on the first one about a third of the way through but people told me "it gets good later"; it didn't. So when I hear people saying that about the trilogy it's a bit of a "fool me once, shame on you" situation.
I had the exact opposite thought - the first book was interesting and thought-provoking, while the other two just piled on more and more scifi concepts that (imo) have been better explored by other authors.
It was tedious, but so was Herodotus. Tedious does not mean uninteresting ...TBP was very interesting; especially the takedown of group-think revolutionary marxists. For example, and purposely vague to avoid spoilage, the young female guard's behavior echoes much of what we're seeing in today's colleges.
I've had good success with the audiobook + ebook combo in general. I'll listen to an audiobook while cooking, showering, etc and read it physically on a tablet or my phone when I want.
I started reading the first book before I started using this method, and abandoned the series a couple times but saw it coming up so often in sci-fi recommendations I kept wanting to get through it
I found the first half of book one elicited no interest in reading in my down time, but was just barely interesting enough to not quit listening.
By the second half of book one and the entire rest of the series (plus the author approved fan fiction fourth book) I completely gave up on the audiobook because the story was so good that I wanted to read it as quickly as possible. I actually switched to reading on my phone in the shower over listening.
It starts off slow but gets good and stays extremely good. One of my favorite series.
It's a three book series. It has a prequel, which adds little to the trilogy. It's highly awarded. It's interesting in that it was originally written in Chinese and it's uncommon for a translated book to make this big of an impact in sci-fi circles.
You see it a lot in space conversations because it covers planetary gravity in an interesting way.
From the perspective of someone who has read 100's of SF books: not really. But if you haven't or if you want to have a taste of what looking at SF through a Chinese lens would look like then it's probably worth it.
I really liked the first book, towards the second and third it got a little bit slow and repetitive. Not anywhere on par with e.g. Hyperion Cantos, but otherwise very good read.
It's written with a different focus than traditional western sci-fi. Pacing is different, characters are unexpected in certain ways, etc. I can see how people don't like the style, I personally enjoyed the 'something different'.
Yep. Some good sci-fi. Each one is a bit different, but terrific. Funny enough I was thinking earlier this week that I should re-read them since it’s been a number of years.
I read maybe half of the first book, and it was so bad I had to put it down. Maybe the translation is dry, or maybe the thin, stereotypical characters wore on me.
If you like such ideas I have a couple good books for you. Not exactly related to this phenomenon but about space...logistics? With regard ET threats especially.
[1] The Three-Body Problem (trilogy)
[2] A Fire Upon the Deep
If you don't want to read the books at least check out the idea of the "Zones of Thought" that is the interesting concept in the second book.
Makes me think of Krikkit in HHGTTG (from whence the view of the rest of the universe was cut off by a dust cloud. When its inhabitants finally did get to see it their immediate reaction was "It'll have to go")
For a VERY different take on this concept, do yourself a huge favour and read “Nightfall” by Isaac Asimov. Just thinking about it sends shivers up my spine.
I don't think so - in every direction we look things appear largely to be the same. It seems entirely reasonable that extends to life. The only limiting factor is we cannot see other planets to find out.
Is that a reasonable assumption to make? I don't think we have any evidence of other places we look being "largely the same" with respect to life conduciveness. It took billions of years for our own planet to achieve multicellular life, which is a significant fraction of our best estimate of the lifetime of the entire universe up to this point.
But the universe is big and there are billions of billions of other planets which could very well have similar conditions, that also exist for billions of years
The question isn't about what's easier to believe, it's about what the evidence supports. The probability for life (or multicellular life or intelligent life or technological life) to evolve on any given planet is strictly between 0 and 1. You can believe what you want, but the facts don't support any stronger statement than that.
Every star system and planet is rare -- unique, even -- if we're specific enough about the details. The hard part is knowing what details are important when we only have a sample size of 1.
That is basically what the anthropic principle says:
the range of possible observations that we could make about the universe is limited by the fact that observations could only happen in a universe capable of developing intelligent life in the first place
Before any of that is possible, a "Cambrian Explosion" is required.
It may be that prokaryotic life is common, but the mitochondria and plastids of eukaryotes took a very long time to emerge (absent for more than half of the total habitable life of the earth).
Emergence of eukaryotes specifically entailed aerobic respiration of the mitochondria, which was a massive increase of chemical energy (when glucose and oxygen are present).
Chloroplasts enabled direct harvest of photons from our parent star.
We are actually older than the plants.
These are going to leave a signature in the gas of an exoplanet, if they happen.
> but the mitochondria and plastids of eukaryotes took a very long time to emerge.
Not an expert, but mitochondria didn't "emerge." Mitochondria co-evolved as bacteria, merged and became organelles through complex protein-import machinery and insertion into inner membranes of protein carriers for extracting energy for the host cell.
You are talking about different semantics. You're talking about a merge in the context of a mechanical process, and they are talking about emergence in the context of speciation. There's no reason to expect the verb to be the same if the subject is different.
There are not "different semantics." There is semantics. It's a mass noun and singular. If you're attempting to hand wave by calling my comment a semantic argument, and therefore insignificant, then you are simply incorrect. Semantics are of vital importance to language and communication. Without semantics, no one would have any idea what anyone else was saying. And my use of "merge" was a pun. Woosh!
I think it is a matter of semantics because it seemed like you have a different understanding of the meaning of the word emerge then the person you are responding to. Within the context of the original post, the word emerge has nothing to do with the physical location of mitochondria and the eukaryotic cell. Instead, the meaning of emergence was to come into existence from non-existence. That is to say, your objection relies on a different semantic understanding of the word used. It is unclear to me if you don't understand this meaning or if you understand it but disagree with others using it.
Similarly, I would argue that a "mitochondria" not living in a parent so is not a mitochondria at all. Again, this is a matter of semantics. It relies on the meaning of the word mitochondria and how it is defined.
Bay way of comparison, is a person who buys a house homeless or a homeowner? Are humans prototocells because our evolutionary history can be traced back to them?
> Similarly, I would argue that a "mitochondria" not living in a parent so is not a mitochondria at all.
I'm not sure why you're continuing to try to make it clear to me that you're not wrong when we simply disagree, but your statement here employs nominal fallacy, or naming fallacy. Mitochondria is that same bacteria that it used to be prior to entering into a symbiotic relationship within the cell. It's a relatively new scientific revelation that mitochondrion organelles lived as bacteria discrete from its current function inside a cell. We may call this that and that this, to keep track of function, but it doesn't mean that a spade isn't a shovel.
1) A thing can have a different name depending on where it is - for example, "power converter mounting bolt" and "control panel cover fastening bolt" might both be M8 bolts, and interchangeable. This isn't any sort of fallacy.
2) In any case, mitochondria have evolved, and are now distinct species from their ancestors that cannot survive outside the cell.
3) Fittingly, a spade is pointed, while a shovel is square tipped.
What about mitochondria? I did not address your mention of eukaryotes, only mitochondria, which existed as bacteria long before eukaryotes. You're intentionally ignoring the error in your OP and my pun: mitochondria did not emerge with eukaryotes, they "merged." Your lack of addressing mitochondria in your response makes it a straw man.
It would be a somewhat safer place for life than within a galaxy proper - far less chance of a close approach by another star kicking your planet out of its solar system, less chance of taking a sterilising hit by a close by gamma ray burst.
Those living on such a planet might even reasonably conclude that advanced life on a planet within a galaxy, like our own, was very unlikely.
Since they're pulled together from the intergalactic medium, I'm pretty sure those stars and everything around them are pure hydrogen/helium. You'd need a few generations of star formation/nucleosynthesis before you could have rocky planets and carbon-based life.
Imagine intelligent life arising on a planet around one of those stars. I wonder how long it would take their astronomers to figure out where they were.
This would be an interesting premise for a science fiction story. You could imagine a species realizing that the only way to survive long term is to keep hopping to new star systems every billion or so years. And when they get ready to hop to another system for the first time, they realize almost all the viable star systems are already colonized by past species who came to the same conclusion
Greg Egan’s Incandescence is along these lines except replace star in the trail of a black hole with asymmetric asteroid around a black hole accretion disk.
I read that, but have either forgotten, or missed the entire black hole thing. I think, for any given Egan novel, I miss about half of the ideas while trying to wrap my head around the other half, but he's still one of my favourite authors.
Would there be a similarity of stars? We see lots of stars because we are in the middle of a galaxy, but they are outside of a galaxy. They could see the galaxy they came from in parts of their sky, but would it really be like actually being in the galaxy? I'd imagine not. It might only be visible from one hemisphere of the planet, depending on how the ecliptic was aligned. The other hemisphere might only see black, with maybe one or more moons and other planets.
I wonder if this is an opportunity to detect intelligent life. If the black hole is affecting any intelligent life on the way, they might do something to save themselves or their planet, which might be detectable?
Please note that the black hole is causing star formation from gas, not moving star systems. From what I gathered from the article, there are very few stars actually in its path, and it is mostly just plowing through a large gas cloud.
If they could do something on a scale to stop (or even avoid) a runaway black hole they'd have to be enormously powerful. I would think even for species well beyond our capabilities the only option would be to flee.
By our current understanding the only thing one could do to a black hole is increase its mass (useless) or attempt to change its path gravitationally (requiring a massive amount of gravity -> requiring a massive, massive amount of energy)
Fleeing probably makes the most sense for any species.
"...when he was looking through Hubble Space Telescope images and noticed a suspected blemish that looked like a scratch on photographic film"
Is it possible for a layperson like myself to spend an evening casually looking through the trove of Hubble images or are they only for astronomers? I googled around but I couldn't find an archive anywhere.
It’s interesting that they used “supersonic” since phenomenon of sound emerges when there is enough molecules to collide with each other to transmit sound waves, which is not the case in the outer space.
But most probable speed of hydrogen molecules at 2.7K is surprisingly low - 150m/s. This speed can be used as “sound” speed approximation in the intergalactic space.
The use of "supersonic" was likely metaphor, but I thought it was funny coming from a scientist, as we expect them to usually speak literally with precise accuracy.
> This intergalactic skyrocket is likely the result of multiple collisions of supermassive black holes. Astronomers suspect the first two galaxies merged perhaps 50 million years ago. That brought together two supermassive black holes at their centers. They whirled around each other as a binary black hole.
> Then another galaxy came along with its own supermassive black hole... One of the black holes robbed momentum from the other two black holes and got thrown out of the host galaxy.
I'm obviously not an expert, and this comment is obviously way off the topic, but allow me to wonder: If one supermassive black hole like the our Sagittarius A* can be that dominance, isn't this makes the black hole the most important "asset" of the galaxy? By that, I mean, if you somehow destroyed the back hole (which is what Kurzgesagt was trying to convince people to do, hehe), the galaxy will fall a part, assuming the bulge alone don't have enough gravity to hold the galaxy together.
If you let me expand this a little: So if there are advanced alien civilizations in our galaxy, maybe they want to take control of that black hole? Since that location is the only location unique in the entire galaxy.
If I can expand this a little further: As we human currently observed it, Sagittarius A* is currently quite stable (???) with no sign of disappearing. Can this suggest that in our galaxy there is not a single civilization advanced enough to (or want to) modify Sagittarius A* in a significant way, or maybe black hole just cannot be influenced easily even for a higher tier civilization (maybe wormhole is too hard too)?
I know I missed many details. It's just a shower thought first came out after I docked at a space station few light years away from Sagittarius A* in the game Elite Dangerous. Throwing the idea out there.
BTW: If someone is going to write a novel based on this, you need to pay for the idea up front :)
Not an expert either but Sagittarius A* has a mass of 10^6 solar masses, the Milky Way itself has a mass of approximately 10^12 solar masses. So I doubt that Sagittarius A* is even relevant in terms of the Milky Ways gravitational potential.
That said, the existence of Sagittarius A* does (most likely, this is an area of debate) have an impact on the Milky Way due to the strong, high-frequency radiation from its accretion disk, which affects the gas surrounding the central region of the galaxy.
Still, this is probably not an incentive for anyone to destroy the black hole (if that were technologically possible).
In addition, keep in mind that any galactic-scale effects take on the order of millions of years to take place. (With supernovas or other super high energy events being an exception)
So my intuition is your novel would need to ignore a few physical facts, but its fiction after all :D
"Can this suggest that in our galaxy there is not a single civilization advanced enough to (or want to) modify Sagittarius A* in a significant way, or maybe black hole just cannot be influenced easily even for a higher tier civilization"
It is also possible, that they don't want to modify the black hole, because it is working as intended?
Why would we change the sun, even if we could?
But apart from that, yes, a civilisation would need to bery very, very advanced to significantly alter a black hole, like the one at the center of our galaxy.
The amount of science that the HST has produced and continues to produce is staggering; however I often comment that I find it a bit sad that most people don't know that we didn't just build 1 of them... we built more than a dozen of them, at a cost that dwarfs the program cost for the HST [0] But only the one with the instruments and mission direction that gives us scientific insight. It feels like such a shame.
What I don’t understand is where the material for the stars is coming from? Is there that much dust in deep space? Or did it collect it from the galaxy?
The primary stuff you need to form stars is hydrogen and helium which is absolutely everywhere in the universe. In order for stars to form, however, you need a lot of it. This usually happens if you have a strong gravitational force, which pulls in more and more gas (very very slowly). If the gas cools sufficiently, at some point the gravitational force will overcome the thermal pressure of the gas, causing it to collapse and form stars.
This is the basic mechanism of star formation everywhere and it probably isn't much different in this particular system. The strongest gravitational forces are caused by dark matter haloes which are usually larger than the galaxy itself and much heavier. On smaller scales, the main gravitational force is caused by the collapsing gas itself. Both probably still exist in this system and provide the required gravity for stars to form.
A note: While dust has an impact on star formation (it might help the gas to cool, for example) it is not a required ingredient for stars to form. In fact, the first stars formed at a time when there was no dust in the universe.
I don't know what the black hole is moving through. That is, I don't know how much "metallic" stuff there is in the cloud. The article says the stars are blue, so presumably large and hot. The article also says the triggering event probably happened about 50 million years ago - so after the death of the dinosaurs on Earth.
The article doesn't say how far away this thing is. If it's very distant, and the Universe we're looking at is young, presumably the gas is mainly hydrogen and helium. Maybe, given another billion years or so, the newly-formed stars will coalesce into a new galaxy?
I had the same question! From what I can gather, the black hole is plowing through gas, when the gas gets too close to the black hole, it gets sucked in and forms a disk around the black hole. As the gas disk spirals in towards the black hole, it gets heated up and shocked, causing it to fragment and form clumps. These clumps eventually collapse under their own gravity, forming stars. How cool is that!
Huh. That's a very interesting find. It's been a while since I took Astronomy and Physics but I thought you get black hole after massive stars fuse all lighter elements up until [Fe]? It must have pulled enough lighter elements in its path of travel to leave enough for star formation in its streaks.
Does that mean halfway across the known universe, or is it just a figure of speech for "a really long way away"? (Or is my assumption that the universe is infinite wrong?)
Since it's been located, it most likely refers to the "observable universe" - the sphere surrounding us (Earth) within which enough time has passed since the big bang that the EMR from the edge has reached Earth. Beyond that we have no idea what's there because that information hasn't travelled long and far enough to each us yet. It's kind of like a physics fog of war.
If you fired a high velocity rifle at the moon and nothing slowed the bullet down (no gravity, air resistance etc), it would hit the moon in about three and a half days.
- Near the center of a galaxy, where stars are so closely packed together that the night sky is filled with bright lights, perhaps illuminating their world to what we experience around twilight, or even brighter.
- Far removed from the center of a galaxy, or even on a rogue star that has escaped its galaxy early on. Very few stars visible in the sky.
- Inside a 'thick' nebula, obscuring all other entities in the sky except for their own star and planets. Imagine an interstellar object like Oumuamua passing through and the complete perplexity of a civilization observing it and wondering where it could have come from.
- A double planet system.
- A system where the planet's orbit is highly elliptic, or where the precession of a tidally locked planet causes day/night cycles.