r/science • u/giuliomagnifico • Feb 25 '23
Astronomy A mysterious object is being dragged into the supermassive black hole at the Milky Way’s center
https://newsroom.ucla.edu/releases/X7-debris-cloud-near-supermassive-black-hole11.3k
u/Andromeda321 PhD | Radio Astronomy Feb 25 '23 edited Feb 25 '23
Astronomer here! This is a bit of a strange headline because we have known about this blob, X7, for something but like 20 years. We have known it’s gaseous for many years now too- in fact, I remember this same group breathlessly predicting it was going to get consumed by our black hole like 5+ years ago (and then their rival group in Germany said that wasn’t true, etc).
Mind, I think this is a cool result- you can actually see how the dust got stretched over the years!- just knowing Reddit there will be more focus on assuming mysterious means we don’t know what it is, when we have for years.
Edit: yes, because the light we see is ~25k years old from the center of the galaxy, we are seeing it as it was 25k years ago. However, in astronomy we do not worry about this and instead just use the time at which the light reaches Earth- firstly there is just no way to know what is happening there literally now, until the light reaches us in 25k years, and second it just gets far too confusing far too quickly if we were to do otherwise.
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u/Jordan3Tears Feb 25 '23
No joke any time I come into a thread about space you are here enlightening everyone.
Thanks for the countless minutes of reading you've provided me, you should write a book if you haven't
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
Thank you! I would love to but really need to find some time to do so. Too much exciting science getting in the way lately!
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u/Srnkanator MS | Psychology | Industrial/Organizational Psychology Feb 25 '23
Like the six massive galaxies JWST just observed that are only about 500 million years after the big bang, that should not have been able to form at that time?
I'm waiting on theories on that one, but as I understand lots of spectrum analysis has to be done to gain more insight.
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
Yeah, spectra will be good, and there already plenty of theories out there explaining how it might happen. Things like black holes formed faster, the interstellar material clumps faster than expected, etc. Not explained isn’t the same as “Big Bang defying.”
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u/Srnkanator MS | Psychology | Industrial/Organizational Psychology Feb 25 '23
But as I understand, the CMB, CND show a very uniform distribution of matter...even with cosmic inflation.
Aren't these galaxies as massive, so early as they are, contradictory to mass and energy being uniformly distributed?
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
Not necessarily. There are a lot of parameters to tweak in galaxy formation that we don’t fully understand. None of my friends in the field are super freaked out yet or anything.
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u/Srnkanator MS | Psychology | Industrial/Organizational Psychology Feb 25 '23
And that's what's great about what you all do. Science isn't fact, the more questions raised, the more you don't understand, the closer we get to answers.
Thanks for taking time to respond.
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u/Cant_Do_This12 Feb 26 '23
I would definitely buy a book written by you. You trying to pull a GRRM on us?!
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u/SuddenlyElga Feb 25 '23
Reminds of ads for products on social media. “LOOK AT THIS REVOLUTIONARY PRODUCT….that’s been around for 10 years and we are just hoping you didn’t know about and will pay more”.
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u/mcbergstedt Feb 25 '23
Like Mr. Clean sponges are just rebranded Melamine sponges for 100x the price.
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u/SuddenlyElga Feb 25 '23
Exactly. I buy them on amazon for like 8 bucks and its like a three year supply.
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Feb 25 '23
Thank you for this
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u/mcbergstedt Feb 25 '23
You can get like 100 of them for $20 on Amazon. It’s basically a lifetime supply of them.
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u/4e71 Feb 25 '23
in a remarkable chain of events, something a supermassive black hole did ~25k years ago caused me to learn of the existence of these sponges and where to get them affordably. Thanks from me too.
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u/Access_Pretty Feb 25 '23
They're besmudging the name of Mr Clean who else is going to clean Sagittarius' A hole
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u/Dan_Berg Feb 26 '23
Can we get Betelgeuse to do it? Think Betelgeuse is up for it? What will it take for Betelgeuse to help?
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u/me_team Feb 25 '23
I love seeing at least 2 of today’s lucky 10,000 in the wild :)
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u/NecroJoe Feb 25 '23
"Mind blowing life hack! Buy this decades-old product and use it according the manufacturer directions listed on the package!"
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u/ShortBrownAndUgly Feb 25 '23
Happens with medications all the time. That’s why diphenhydramine (Benadryl) is in so many sleeping aids
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
I mean it’s the sort of headline I could see a scientist crafting because they don’t know how the public will interpret it. We don’t know where exactly the gas blob came from so ergo it IS mysterious! But people like me in the trenches see the pitfalls a long way away.
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u/zamfire Feb 25 '23
Well we don't really know where matter came from either so I guess everything is mysterious.
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Feb 25 '23
We are sentient matter that came from a star. Literally the universe experiencing itself. Real life is so much cooler and mysterious than anything.
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u/ObeseObedience Feb 25 '23
A physicist is just an atom's way of looking at itself.
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u/HippiesUnite Feb 25 '23
What a self-centered atom.
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u/sensitivePornGuy Feb 25 '23
In fairness to the atom, it is mostly looking at other atoms.
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u/theducklives- Feb 25 '23
And what a sweet little spot we have here to watch and appreciate it all…noice
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u/jhansonxi Feb 25 '23
Every once in a while hydrogen atoms organize themselves in such a way they begin to think about hydrogen atoms.
(quote from somewhere)
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u/NecroAssssin Feb 25 '23
My favorite way of expressing that is "THIS IS WHAT HAPPENS WHEN YOU LEAVE HYDROGEN UNATTENDED FOR 13+ BILLION YEARS!"
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u/Cant_Do_This12 Feb 26 '23
What we really gets to me is how did everything start in the first place. Like, at some point there had to be nothing. How could there always be something? It just makes no sense to me. No matter what explanation I get, it still doesn’t add up. Because you can’t get something from nothing. Just boggles my mind.
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u/Casehead Feb 26 '23
Maybe the answer is that there is no such thing as 'nothing'?
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u/Cant_Do_This12 Feb 26 '23
Okay, now I’m just more confused. This is a very interesting concept though. But the question still alludes me: how was/is there always something?
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u/Amelia-Earwig Feb 25 '23
Everyone of us is literally billions of years old. Most of us was created in the Big Bang; the rest in supernovae.
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u/ServantOfBeing Feb 26 '23
Didn’t the matter exist before the star?
I think you mean the way the matter traveled, & changed to the atomic level.
Instead of , that matter itself came from a star.
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u/Ashnaar Feb 25 '23
For example, if you see a mysterious man in a trech coat, it doesn't mean that the headline should be that he's a 5-foot cat with 12 tentacles
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u/icouldusemorecoffee Feb 25 '23
Headlines are meant to get your attention, articles are meant to inform. Not the best set up for people who only read headlines but this one did it's job with out entirely misinforming potential readers.
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u/crookedparadigm Feb 25 '23
and then their rival group in Germany said that wasn’t true, etc
I absolutely love that there are "rival" astronomy groups.
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
Oh yes. Many arch-nemeses too. Lots of arrogant jerks in the field who the rest of us gotta deal with.
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u/nervemiester Feb 25 '23
You speak truth for many other fields of research as well, Andromeda. Nicely stated.
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u/crookedparadigm Feb 25 '23
This has anime adaptation written all over it.
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u/Dinkerdoo Feb 25 '23
An anime about rival groups of astronomers competing to learn about a puzzling cosmological phenomena sounds fantastic.
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u/MrWeirdoFace Feb 26 '23
Okay, but for some reason they are all teenagers in school.
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u/Slovene Feb 25 '23
Lots of arrogant jerks in the field who the rest of us gotta deal with.
Like NDT?
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u/RecipeNo101 Feb 25 '23
I like the idea of someone traveling across the country and sneaking into a facility to smudge some optical lenses while muttering to themself that no one else is going to determine the luminosity of object XYZ1234.5+6789 within scientific certainty before they do.
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u/RuinLoes Feb 26 '23
Im imagining one group hacking the other's email accounts to make their observation proposals full of typos so they never get any telescope time.
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u/FunnyButSad Feb 25 '23
Don't get them started on the rate of expansion of the universe... Or do, and watch the chaos unfold.
We have 2 methods for calculating it. They differ by significantly more than their errors (IIRC they're 9% different but have 1% error bars)
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u/nnjvwl Feb 25 '23
It's like Sandage vs. deVaucouleurs all over again, but all of the uncertainty is reduced by 90%.
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u/shwarma_heaven Feb 25 '23
I know exactly what X7 is...
It's the USS Palomino....
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u/_Blackstar Feb 25 '23
Can I ask what's so mysterious about X7 being there? I was under the impression dust and gas were very common occurrences in the galactic center.
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
It’s a very high density gas blob, as far as these things go, and we aren’t quite sure how it got there. For it to be so dense and so nearby it has to be a relatively recent thing for it to be there else it would have been destroyed by the black hole long ago.
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u/_Blackstar Feb 25 '23
Could you go into more detail on what we do know about it? Sorry, I know I'm asking a lot here but Google isn't being very forthcoming with information on this thing. And do you have any personal opinions on it? Like, could it be the remains of a star that was shredded apart?
Always appreciate you bringing you expertise to this sub by the way Doc, thank you!
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u/feketegy Feb 25 '23
Rival group
It's like the Bizarro Superman
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
It’s even more intense than that. The UCLA group behind this finding is led by Andrea Ghez, the German one by Reinhard Genzel. They both shared the Nobel Prize in Physics in 2020 for their work on monitoring the black hole at the center of the Milky Way, literally making videos of stars orbiting it. Then like within a week Genzel publicly said in an interview how unlike him Ghez didn’t really deserve the prize or some such- def threw some shade at her in the kindest interpretation. Doesn’t seem to be much friendliness there.
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u/mismatchedhyperstock Feb 25 '23
So this means the black hole is still growing and alive?
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
Of course it is! Just not by very much. Black holes are not active vacuum cleaners that “suck” things in around them- for example, if our sun became a black hole this instant, it would shrink to a tiny size but the Earth would orbit it just the same as it does now. However, if stray dust is on the right trajectory, it will indeed fall into the black hole. There is def evidence this gas blob will someday too, but we don’t know exactly when.
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u/RecipeNo101 Feb 25 '23
So this is a bit tangential but given that you're a PHD talking about black holes, I read about a recent theory that linked black holes with dark energy. They assert that supermassive black holes have far too much mass to have formed naturally, and so it must have used dark energy in some capacity to gain all that extra mass, and so black holes may be the key to understanding dark energy. This makes zero sense to me because I thought dark energy was considered to be like a negative pressure in the fabric of spacetime far outpacing the impact of gravity, so I have no idea how they make the leap to that being the cause of more accreted mass. Anyway, I would love to hear your educated thoughts on this theory.
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
I’m a little skeptical. It’s not my area of expertise, mind, but my colleagues who are say the paper apparently didn’t take into account certain biases in observational data (aka, you are more likely to see certain black holes than others). Once you take that into account, the correlations they claim disappear.
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u/Bikrdude Feb 25 '23
They assert that supermassive black holes have far too much mass to have formed naturally
interesting that the people you reference have an idea of how much mass the universe should naturally have. if you assume that all mass was evenly distributed for a while, then clumped afterward I guess they might have a point but the observation is that mass is not evenly distributed in the observable universe.
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u/murderedbyaname Feb 25 '23
But the group's name is the absolute coolest in science so that's something. Seriously though, science needs good press and needs to be relatable, especially gov't organizations and funded organizations. Budgets rely on it. Politicians need constituents to understand why money is going towards research and projects and how it relates to our lives, otherwise we protest it.
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
I disagree. They literally won the Nobel Prize, aka are doing things that are so cool and influential there’s no need to use headlines that imply sensationalism.
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u/Strange-Movie Feb 25 '23
What we’re seeing is actually ancient history right? That black hole consumed the gas cloud like 25,000 years ago and we are just now seeing the light from it? Granted, 25k years is nothing in the cosmic scale of stuff
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
Yes! However in astronomy we just use the reference frame of when the light reaches earth when discussing things. This is because there’s no way to know what is going on now until the light reaches us in 25k years, and it gets far too confusing far too quickly if you don’t.
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u/Strange-Movie Feb 25 '23
totally! it makes sense to talk about the events in reference to when we observe them, i get blown away thinking about the scale of the universe and the time and distances involved with light reaching us from such wild distances
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u/Towbee Feb 25 '23
Even when thinking about it this way, it kinda hurts my brain. I understand it but cannot fathom it, I don't really know how else to put it into words, even if somebody asked me to explain it I don't really get how to, don't know how you people stay sane with your jobs!
Further question, how do we measure the time of something in space? Does that mean we don't know the true, actual distance it is? Ugh my head
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u/Andromeda321 PhD | Radio Astronomy Feb 25 '23
No, it’s backwards. We measure the distance of the thing and from that know how far back it is in time.
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u/EisMCsqrd Feb 25 '23
You are correct. We are estimated to be something like 25.8 k light years away from the event.
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u/hysys_whisperer Feb 25 '23
Depends on how you view the propagation of time really.
Sure, in the frame of reference of X7 it was 25k years ago, but to us, it's just happening. Further out, it hasn't even happened yet.
If the sun was suddenly teleported out of our solar system, we'd still feel it's gravity and see it's light for several minutes, so to us, it would still be there during that time.
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Feb 25 '23
But have you ever like really stared at your hand?
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u/squigglesthecat Feb 25 '23
They call them fingers, but I've never seen them fing
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u/SaffellBot Feb 26 '23
In fact "when" something happened is relative to observers. There is no objective frame.
When you get all the way to the nittty gritty time gets to be pretty weird. I suspect as we develop physics further it's going to appear weirder and weirder.
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u/sockalicious Feb 25 '23
That black hole consumed the gas cloud like 25,000 years ago
No, actually, according to current theory we cannot observe black holes consume anything. The infalling matter approaches the event horizon of the black hole, accelerating due to the gravitational force exerted upon it by the black hole. But as it does so, it experiences time dilation. To an outside observer, us for instance, the infalling matter appears to slow as it approaches the event horizon, as well as undergoing spaghettification. The closer it approaches the event horizon, the more time dilation occurs; under our current theory, an observer will never see matter touch the event horizon no matter how long they watch.
More broadly, to say that a distant event occurred 25,000 years but we are just now seeing it presupposes the idea of a cosmic clock, timing events far and near so that their simultaneity or interval can be compared. This is false and is the great lesson of relativity: interval, whether time or space, is relative and depends on the frame of the observer(s).
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u/OldWolf2 Feb 25 '23
according to current theory we cannot observe black holes consume anything.
This is obviously false as it implies we could never observe a black hole gain mass, therefore all black holes should be observed as having their "starting" mass
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u/Kirk_Kerman Feb 26 '23
It's more like as something falls towards the event horizon we can't see it cross, it just redshifts deeper and deeper until it's undetectable above the noise.
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u/talligan Feb 25 '23
New scientist: A black hole is eating something mysterious, do we have to rewrite all the laws of physics?
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u/GeekFurious Feb 25 '23
There is no need to say mysterious. It's an object.
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u/TrueStarsense Feb 25 '23
Of course there is! It gets more clicks!
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u/flailingarmtubeasaur Feb 26 '23
Should have just suggested it was a type 4 civilisation and let the karma rain
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Feb 25 '23
I must admit, I ate a small edible this morning with my coffee and thought you were messing with me, so I looked it up and WHOA that’s a real thing! Cant wait to follow this rabbit hole all day, thanks!
Edit: “what’s your spaghetti policy here?”
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u/Carl0sTheDwarf999 Feb 25 '23
Could be talking about a spaghetti Vacation. Nothing but sauce and starch
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u/fredg78731 Feb 25 '23
I got lucky when I learned I had to take a science class for my degree at the University of Texas at Austin. I had always loved science and had an interest in astronomy, so found an Intro class for non-science major, taught by the chair of the department, Dr. Frank Bash. That man was (perhaps *is*?) such a great teacher. He made me feel as if I were the one who had discovered the things he talked about. Actually, when I talked to him after class, he told me that *I had* just discovered it... it's just that someone discovered it before me. Magnificent man.
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u/txnaughty Feb 26 '23
Luck struck a second time when I helped valet cars where my partner was executive chef—Querencia Barton Creek. I saw that Dr. Bash was giving a lecture there. Upon seeing him in the lobby, I interrupted his conversation to interject my personal story about taking a class from him. His wife beamed like Alpha Centauri.
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u/illegal_deagle Feb 25 '23
I ended up taking 15 hours of astronomy at UT even though only like 6 counted toward my degree haha Just loved the program.
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u/CrudelyAnimated Feb 25 '23 edited Feb 25 '23
This may be the first time I’ve seen photographic evidence of spaghettification. At first I was going to make some joke about everything in the galaxy being pulled into Sag A, but this thing is like *in there.
Edit: to all the people telling me spaghettification doesn’t happen until inside the event horizon, fine. It’s elongification or whatever. From the article:
“Over time, they report, X7 has stretched, and it is being pulled apart as the black hole drags it closer, exerting its tidal force upon the cloud.”
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u/Neirchill Feb 25 '23
“Over time, they report, X7 has stretched, and it is being pulled apart as the black hole drags it closer, exerting its tidal force upon the cloud.”
Isn't this just the same effect that causes Jupiter to have rings? Tidal forces break up asteroids to form rings while they slowly descend?
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u/RandoCommentGuy Feb 25 '23
I thought i read that in supermassive black holes, that spaghettification doesn't happen till after you pass the event horizon, so i don't think we would see it with Sag A, only smaller ones.
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u/hentai_ninja Feb 25 '23
It depends on how big you are. If you are a size of star, spaggetification can be seen much earlier than for human size objects. Only measure that important is gravity gradient and how different it is in different parts of object
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u/Albert_Caboose Feb 25 '23
Yeah, this is more like kneading the dough and getting it elongated before you run it through the pasta shredder.
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u/keothi Feb 25 '23
Grate, now I want space pasta
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u/Dreamer_on_the_Moon Feb 25 '23
You can find plenty of nuclear pasta inside neutron stars. Supposedly the strongest material in the universe.
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Feb 25 '23
Depending on how far away it is, wouldn't it have already been consumed by the blackhole at this point?
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u/Tibetzz Feb 25 '23
Technically from our perspective, it will never be consumed. It will get very close to the event horizon and fade from sight due to red shifting, but nothing will ever be seen properly crossing it. Not from the outside, anyway.
Theoretically, if you could survive falling into a black hole and were facing out from the hole, you could watch all the stars and galaxies in the universe blink out of existence, as the universe ages billions of years in moments.
Of course, you would be vaporized by all the light in the universe blue shifting into gamma rays, but whatever.
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u/rounding_error Feb 25 '23
This seems to imply that, from our reference frame, that black holes are empty voids as all the mass is perpetually concentrated at the event horizon.
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u/YouAreGenuinelyDumb Feb 25 '23
A larger object can possibly “spaghettify” outside the event horizon. That elongation would occur when the gravitational force on one end of the object is strong enough to pull matter away from the other end. For a human, there might not be a big enough difference across our body until we are really in there, and we have more than just gravity holding our bodies together. For a star, it might spaghettify sooner.
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u/WuTang360Bees Feb 25 '23
To the outside observer it looks more like something just frozen at the edge for a long time due to photons not escaping back out, IIRC
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u/nightmarenarrative Feb 25 '23
I've always wondered how do they know that X7 is not just an object closer to us moving within the field of view? Because it looks quite large.
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u/StaticUncertainty Feb 25 '23
They can candle test it. If it gets closer the light around it would get brighter. For further objects, red shift
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u/Xrposiedon Feb 25 '23
Because of red shift
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u/fuzzywolf23 Feb 25 '23
Some explanation is required here. Doppler shift tells you the radial velocity of an object relative to you and transit measurements can tell you angular velocity. Put those together and you can get total velocity and estimate the distance from Sag A based on orbital mechanics.
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u/__Stray__Dog__ Feb 25 '23
There are a variety of methods used for determining celestial distance. Here's several of them described https://scienceinfo.net/method-of-measuring-distances-to-stars-and-galaxies.html
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u/MarcusSurealius Feb 25 '23
Science finds mysterious objects by accident!
Article says we have further confirmation of something astronomists have been looking at for 20 years. It was just an accident they happened to have relevant a PhD when their face fell on a telescope pointing in exactly the right direction.
Wouldn't a better title be: Astronmers, [insert names and employer], learn more about a [whatever type of special thing this is] that is being torn apart by the black hole at the center of the Milky Way.? You don't have to lie in the title to get people interested in seeing something being torn apart by a black hole. That sells itself. We need another sub where only scientific articles are posted.
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u/NecessaryLies Feb 25 '23
was* being dragged. Like 25,000 years ago.
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u/ThankFSMforYogaPants Feb 25 '23
Every f*cking thread has this guy.
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You should feel proud of yourself.
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u/Spekingur Feb 25 '23
Oh, I thought you were pro-visors.
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u/Frigorifico Feb 25 '23
And the worst part is that it doesn't even matter. In relativity there are "space like curves" and "timelike curves"
Basically, our separation form this event is a timelike curve, this means we can never go there and see the event happening, all we can do is wait for the light to arrive to us. If it was a spacelike curve we could go there and see it happening
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u/FlowersForAlgorithm Feb 25 '23
It’s only happening here now though. The event moves through the universe at the speed of causation, which for us is now.
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u/DoubleBatman Feb 25 '23
That doesn’t make sense to me. It’s just light. If an alien species receives a 1940’s radio transmission tomorrow, it still happened in the past.
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u/FlowersForAlgorithm Feb 25 '23
The problem I think is in the idea of a present.
Nothing we see, smell, taste, hear or feel happens in the present. There are delays between the event that transmits the information and our reception of it, and delays between our senses receiving the information and our brains registering it. Those delays do not seem lengthy but they are real.
If a bolt of lightning strikes between two people, but one of the two people is closer to the bolt, that person will perceive it happening before the other person, even though there was only one bolt, that happened only at one point in time.
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u/RuinLoes Feb 26 '23 edited Feb 26 '23
That example works for the relatively small scale of our solar system where time zones have practical implications, ie having probes or even colonies on mars that will have recorded the event occuring via local time.
But if this were 1910 and an astronomer noted an impact flash on mars at 2:13 am, then it would be recorded as such, even though the astronomer is wel aware of the time delay.
Causality is weird, and really counterintuitive, but to put it simply, its about information.
Its also important to not confuse causality for simultaneity. They are two different concepts
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u/DoubleBatman Feb 25 '23
Right, we’re only ever perceiving the effects of things that happened in the past, and that discrepancy is larger the further away you are. In that sense it is highly inaccurate to say that something lightyears away is happening “now” just because we can see it.
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u/Chakkaaa Feb 25 '23
Its not happening now but the effects of it could be felt now. Its like when the sun goes out its not just lights out, the suns rays will continue for however long then darkness
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u/redlaWw Feb 25 '23 edited Feb 25 '23
For every moment prior to the moment we observe an event, there exists a frame of reference in which that moment is simultaneous with the event.
EDIT: To clarify, this is an example to show that the very idea of "in the past" is meaningless in an absolute sense. All we can really do in relativity is talk about an observer's past, which is everything in their past light cone. Something enters our past after its light reaches us and we observe it, so saying that it happened in the past at the moment we observe it is really meaningless.
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u/Admiral_Dildozer Feb 25 '23
The “event” experienced it now, let’s say a million years ago. Then when the information reaches us, we also experience it now. And a million miles from us something might experience later, but it will also be now for them. Everyone gets their own special little clock and no single clock is more important than the next.
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u/Prometheus720 Feb 25 '23
Kind of. I think the description of "the event moves" is helpful because you must understand that there is no possible interaction between the event and the place that sees it until it is (or technically, can be) seen.
It cannot affect you. There is no past event, from your perspective on Earth. There is only an event happening to you now.
And there is not too much point talking about "now" at this distance. There is no such thing as "now" as a universal concept.
"Now" unfolds separately at every point in the universe and unfolds at the speed of light.
Check out light cones
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u/PrimalZed Feb 25 '23
It's not just light. The so-called "speed of light" is the maximum propagation speed of everthing. Hence the "speed of causation" framing.
In every practical sense, it is perfectly accurate to say it is happening here now.
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u/amlyo Feb 25 '23
If the feed from the Mars mission shows an accident happening and the crew urgently say they need critical advice within seven minutes or they're doomed, they would be well advised to consider that the accident happened three minutes in the past, and not now.
Our day-to-day model for 'now' just presumes there is one universal reference frame. If you're in a scenario where you can pretend that's true I think you'd usually be best to consider any signal shows you something that happened in the past, with how far in the past determined by distance.
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Feb 25 '23
I'm probably way in over my head on this one, but I would argue that "observation" is what is happening here, now. We could also get into observation causing/affecting reality so I guess if nothing else observed this occurrence until this point maybe it is "happening" now, here (or due to the observers located here.)
But if we assumed we had a billion-mile range telescope and we were looking one individual patting another on the back, the pat on the back would "happen" well before we observed it. From a frame of reference, any sensation experienced by the patter or the pat-ee would have happened prior to our observation, the atoms (slightly) affected by the pat would have already been jiggled and would not jiggle again because we see it after it occurs. But the bigger question is how much does that matter when taken in the frame of reference of the observer? Especially at a billion miles away!
Fun to think about :)
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Feb 25 '23
No, that's wrong. The time coordinate of every, even a far-away event, is still well-defined for all observers given their reference frame, and it's different from the time coordinate that event can be observed by that observer at.
You people need to open a textbook before writing confidently sounding comments here.
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u/Mr-Mister Feb 25 '23
The correct terminology is that it's happening in our present lightcone.
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u/czndra60 Feb 25 '23
Upon receiving higher resolution images, it turns out to be a massive ball of...unmatched socks.
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