[HN Gopher] Astronomers see a black hole awaken in real time
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Astronomers see a black hole awaken in real time
Author : croes
Score : 189 points
Date : 2024-06-19 10:57 UTC (12 hours ago)
(HTM) web link (www.eso.org)
(TXT) w3m dump (www.eso.org)
| Waterluvian wrote:
| Is there a convenient listing of the timeframe of cosmic events?
|
| I have a poor sense of when we're talking hours, years, decades,
| millennia, MA, GA. Might make for a really cool static website
| project.
|
| Same with geologic events, too!
| rodolphoarruda wrote:
| The most relevant event to us here is the arrival of
| Trisolarans in about 400 years.
| djtriptych wrote:
| which event are you referring to?
| nashashmi wrote:
| to go from a supernova to a black hole, it takes a couple of
| days. For a galaxy to be rearranged by a black hole, it take a
| couple of millennia. (my information is not precise nor the
| latest, so it could have been revised recently.)
| dylan604 wrote:
| > (my information is not precise
|
| you're in good company. most cosmological "dates" are not
| precise. for example, the age of the universe is suspected to
| be about 13.7 billion years +/- 20 million years. That's a
| really big +/- in years, but just 0.2% tolerance. the size of
| milky way is estimated at 26.8 +- 1.1 kiloparsecs. again,
| that's a lot of miles/kilometers of a range. it's not like
| they can run out and "pull tape" to take that measurement.
|
| it's one of my favorite quirks of astronomy. of course even
| the tolerances/variances are going to be astronomically
| large.
| lukan wrote:
| I apologize in advance, but I still point to the relevant
| comic:
|
| https://xkcd.com/2205/
| mr_mitm wrote:
| I don't get it. Isn't precision always relative? Who cares
| how large the numbers sound in certain units?
| oh2aa wrote:
| No, precision or error can measured in absolute or
| relative terms. In either case, the unit is irrelevant,
| you could say +/- "0.000001 big bang timespan." The point
| is that in the realm of human experience, that tracking
| error is quite big.
| AnimalMuppet wrote:
| Could you define what you mean by a galaxy being "rearranged"
| by a black hole?
| nashashmi wrote:
| The theory behind spiral galaxies is that a black hole of
| considerable magnitude and time lies right in the center.
| Gravitational waves spirals out for millennia. They start
| moving towards the center but also move towards each other.
| Closest stars move towards the center and other stars begin
| following the close stars and so on. This should ordinarily
| end up like an octopus with multiple arms extending from
| the center outwards. But then the Universe must also be
| rotating like a disc. And so the galaxy spirals out with
| curved arms instead.
| AnimalMuppet wrote:
| So, yes, we think there is a massive black hole at the
| center of all (or just spiral?) galaxies. And
| gravitational waves move at the speed of light, so if
| something changes the mass of the central black hole, and
| the galaxy has a radius of 25,000 light years, it will
| take 25,000 years for that wave to propagate out to the
| rim of the galaxy, rearranging things along the way. But:
|
| 1. The massive, central black hole did not come from a
| supernova. There are no stars anything like that big.
|
| 2. Even if there were a huge central mass and it
| collapsed, that doesn't actually change the mass
| distribution as far as the rest of the galaxy is
| concerned. There is very little change to propagate. The
| existence of the huge central mass would have already
| "arranged" the galaxy.
|
| 3. Galaxies spiral with curved arms due to their own
| rotation, not due to the universe's rotation. If the
| universe were rotating like a disk (and that was causing
| the spiral of galaxies), then you would expect the spin
| of galaxies to all be aligned. And they aren't; not at
| all.
| foota wrote:
| Fun fact, supernovae take only seconds to undergo extremely
| violent processes that typically result in their explosion.
|
| E.g., "Within a few seconds of the collapse process, a
| substantial fraction of the matter in the white dwarf undergoes
| nuclear fusion, releasing enough energy (1-2x10^44 J) to unbind
| the star in a supernova."
| jvanderbot wrote:
| I've always wondered how realistic the timing was for the
| supernova explosion at the end of The Fountain. Seems they
| didn't do so bad!
| Fezzik wrote:
| Extending the tangent: The Fountain is a criminally
| underrated movie!
| lukan wrote:
| It means not the creation of a black hole (like I initially
| thought), but an activity by the hole to blast out gas and
| energy.
|
| "In late 2019 the previously unremarkable galaxy SDSS1335+0728
| suddenly started shining brighter than ever before. To understand
| why, astronomers have used data from several space and ground-
| based observatories, including the European Southern
| Observatory's Very Large Telescope (ESO's VLT), to track how the
| galaxy's brightness has varied. In a study out today, they
| conclude that they are witnessing changes never seen before in a
| galaxy -- likely the result of the sudden awakening of the
| massive black hole at its core."
|
| "Follow-up observations are still needed to rule out alternative
| explanations. Another possibility is that we are seeing an
| unusually slow tidal disruption event, or even a new phenomenon"
| logtempo wrote:
| I guess "black hole awaken" is a more attractive headline than
| "black hole fart" !
|
| It's really cool to see that we have so much instruments, we
| can actually monitor (a very small part) of the universe
| activity.
| q1w2 wrote:
| A more correct title is "Galaxy brightens and scientists
| suspect it might be due to the galaxy's black hole"
|
| There is no direct evidence the black hole is doing anything
| - it's just the only theory we have.
| prewett wrote:
| > It means not the creation of a black hole (like I initially
| thought),
|
| There was a candidate for a stellar collapse to a black hole a
| few years ago:
|
| https://www.livescience.com/disappearing-star-black-hole-no-...
|
| Unfortunately it's in a galaxy far, far away, so we couldn't
| see the star directly, we just saw a characteristic emission
| line disappear without a corresponding supernova. Given that it
| seemed like a large star, one possibility is direct core-
| collapse.
| revskill wrote:
| I should know this 4 years ago
| api wrote:
| What if we are quietly watching from a distance (in both space
| and time) as thousands of civilizations are helplessly irradiated
| to death by gamma rays?
| lukan wrote:
| Or enlightened and transformed to a higher dimension?
|
| The answer is probably the same. We would not know and continue
| our daily chores.
| robofanatic wrote:
| What we are watching right now has happened millions of years
| in the past.
| nikbackm wrote:
| It's not likely that life will survive long enough to form
| civilizations that close to a black hole. It has probably fed
| like this many times before already.
| denton-scratch wrote:
| > that close to a black hole
|
| _How_ close to a black hole? This isn 't a common-or-garden
| black hole, it's supermassive. If it's (300M years ago)
| suddenly started producing intense radiation that we can
| measure here, then I assume that anyone in the galaxy that
| can see the central region is receiving _a lot_ of radiation,
| as well as a storm of high-energy particles.
| greggsy wrote:
| It's around 300 million light years away, so this technically
| occurred a long time ago in a galaxy far far away.
|
| With that in mind, I can imagine that millions of voices
| suddenly cried out in terror and were suddenly silenced.
| dylan604 wrote:
| So what you're suggesting is that this might be a blast from
| the Death Star and we just saw Alderaan get wiped out?
| slowmovintarget wrote:
| No. The scale is galactic, not planetary.
| BubbleRings wrote:
| > ... _now_ radiating much more light at ultraviolet...
|
| I noticed that too <grin>
|
| Is this too far away to try to detect the gravitational
| waves, if it made some? I forget, do gravitational waves
| travel at C?
| danparsonson wrote:
| https://en.m.wikipedia.org/wiki/List_of_gravitational_wave_
| o...
|
| Seems well within range; and yes they travel at C - there
| have been some LIGO observations that were successfully
| correlated with more traditional (e.g. optical or radio)
| observations.
| HarHarVeryFunny wrote:
| Well, some alien species a few hundred million light years
| away, with a big telescope, could be currently watching the
| Chicxulub meteor hit earth, and all the dinosaurs subsequently
| starving to death.
| BurningFrog wrote:
| 65 million light years away, unless there is a system of
| giant mirrors out there.
|
| It is a nice thought though. That was a real rough day for
| Earth, but we turned out alright in the end.
| steve_adams_86 wrote:
| It just occurred to me that if dinosaurs never existed here
| and we found them somewhere else, they'd be such an
| incredible discovery. We're lucky to have such an awesome
| history of life on this planet.
| lukan wrote:
| "We're lucky to have such an awesome history of life on
| this planet."
|
| We are probably lucky, to have life at all.
| vlovich123 wrote:
| Humans are probably unique. Intelligent life probably not
| and life at all is likely commonplace. It would be quite
| a miracle if given the size and scale of the universe
| Earth is the only place where life arose and also managed
| to evolve multiple intelligent species also emerged
| (cephalopods, dolphins, elephants, and primates at least)
| wruza wrote:
| It depends. If simple life is common, how rare is GOE or
| a similar event? If GOE is not that rare, it feels like
| intelligent life is just a matter of time, ice ages and
| enough branches to grab on. Otoh if we are the result of
| a long domino chain, the universe life is screwed.
| withinboredom wrote:
| Reminds me of "Carl's Doomsday Scenario" where they pick
| up a pet that happens to be an "a species seeded on all
| life-supporting planets, but a nasty asteroid caused them
| to go extinct here. I believe they are called
| 'Velociraptors' here."
| BurningFrog wrote:
| Dinosaurs were only first discovered in 1824:
| https://www.cnn.com/2024/01/01/europe/megalosaurus-first-
| din...
|
| It must have been an incredible discovery at the time.
| mensetmanusman wrote:
| They were actually boiled alive due to reentry of earth rocks
| back to earth heating the atmosphere.
| mensetmanusman wrote:
| The death of one individual is a tragedy, the death of a
| billion civilizations is an HN comment.
| qwertox wrote:
| Correct link is now https://www.eso.org/public/news/eso2409/
| instead of https://www.eso.org/public/germany/news/eso2409/,
| which is leading to a login page.
| stronglikedan wrote:
| Maybe regional. I'm not getting a login page in the US, but I
| am getting the German language page. Of course, I like your
| link better, since my German is very rusty (non-existent,
| really). Thanks.
| Udo wrote:
| Even when I click on the correct link I get forwarded to the
| German page anyway. Granted, I'm in Germany, but I absolutely
| hate this behavior.
| NVHacker wrote:
| Anyone else finds the "real time" attribute hilarious in the
| context of these cosmic events ?
| tekla wrote:
| No because light-speed is the speed of causality. It is by all
| definitions, real time
| mulhoon wrote:
| You've just blown my mind.
| yesbabyyes wrote:
| Another mind-blowing perspective is from that of a single
| photon; since time slows when approaching _c_ , from its
| perspective it's eternal, and, since distance shrinks when
| approaching _c_ , from its perspective it's also
| omnipresent.
| d1sxeyes wrote:
| Well, it's not exactly eternal, it's that time is not
| passing for that photon. It's also (as far as I can tell)
| only correct to say that distances shrink as speed
| increases when you're talking about massive objects. A
| photon would not experience space contraction in any
| meaningful way.
| EncomLab wrote:
| You are conflating reference frames - it determines causality
| in your local reference frame but not in any other reference
| frame. The concept of "real time" - like all time - is
| entirely relative to the reference frame you are using.
| wruza wrote:
| Correct, there's no global timeline, so it's not clear what
| "just" 300M years ago even means. Some RFs seen it already,
| and some will never see it. But in ours it happened in Jun
| 2024. It's 300M light years away, not ago.
| mfranc42 wrote:
| But there is a global timeline. The age of the universe
| itself. It happened when the universe was roughly 300M
| years younger. Somebody might say the universe was
| created a year ago if they traveled through it extremely
| close to the speed of light. But we know how fast we
| travel by measuring redshift/blueshift of the cosmic
| microwave background and it's definitely far from any
| relativistic speed. There must be some effect of gravity,
| but that is also within a rounding error. So, I'd say we
| are much closer to the "truth" than somebody who travels
| through the universe a few percent of the speed of light
| or "lives" right next to the supermassive black hole.
| Whether something we will never see exists or happens is
| a philosophical question akin to "if a tree falls in the
| forest..."
| BearOso wrote:
| At the center of the black hole, time has relatively stopped
| with respect to us. So, yes.
| onetimeuse92304 wrote:
| It is not hilarious, it is actually the correct use of the
| term.
|
| Otherwise, you would have to contend with the fact that "real
| time" does not exist at all, as information about any event has
| to necessarily take time to travel to reach you.
|
| So no "real time" coverage of anything -- the information
| always takes time to travel the distance.
|
| What is not a correct understanding of how time works is
| claiming that it happened some thousands of years ago. No, from
| our reference frame it happened now. It is meaningless to say
| that it happened thousands of years ago because it happened
| thousands of years ago in some other, arbitrary reference
| frame.
| yoav wrote:
| You're using reference frames incorrectly.
|
| It didn't happen in real time, but they did observe in it
| real time.
|
| One is a measurement of the event and one is a measurement of
| when the photons reached us.
| baq wrote:
| we saw it happening in real time from here. does it even
| matter here that elsewhere sees it at a different time?
| anyonecancode wrote:
| This is why any faster-than-light travel must either be
| impossible or mean that that traveling backwards in time is
| possible.
|
| I point my telescope at a planet four light years away (I
| have super advanced telescope that can see these details),
| and use a worm-hole or other plot device to teleport
| instantly to that spot. Where do I arrive -- at what I
| observed, or at some point in empty space because I've just
| arrived at where that planet was four years ago?
|
| If the former, I must somehow have traveled back in time by
| four years to arrive at the spot I had observed.
|
| If the latter, I suppose we could instead say our
| destination is where we calculate the planet will be four
| years from now. Except that my travel time was
| instantaneous, so again either I've arrived too early and
| need to wait around for four years, or I jumped 4 years
| into the future (at which point that's not really FTL
| travel, just kind of stepping outside of time into some
| nether state for four years).
| bamboozled wrote:
| Yeah, it's old news.
| insane_dreamer wrote:
| "as it unfolded" would be more accurate than "real time"
|
| Technically, one can argue that "real time" is relative to the
| time frame in which we observe something, but that's not how we
| generally use "real time", but rather we use it to define an
| event that is observed at the same moment (or very close to)
| the moment in which it occurs, such as a match broadcast live
| on TV (though there is some delay).
| wruza wrote:
| We say that it happened in the past, using our wall clock
| ideas. But you can't rush there and look back to "see
| dinosaurs", so it's at least as correct to say that it happens
| in real time. This is an event, registering _now_ in _our_
| reference frame. Nothing else provided.
| nashashmi wrote:
| shower thoughts:
|
| Galaxies of stars are like people traveling through the cosmos
| together in one group.
|
| Elliptical galaxies have a direction of travel, that is why they
| are elliptical.
|
| A galaxy gets it first massive supernova, and a black hole is
| formed, and it becomes a spiral galaxy, kind of like when a
| seismic social event happens and everyone gets in line.
| spacecadet wrote:
| shower thoughts:
|
| - bubbles in water act like black holes
|
| - the universe itself may only be a bubble among many
|
| - the multiverse looks like foam
| danparsonson wrote:
| You might enjoy this if you haven't already seen it:
| https://youtu.be/71eUes30gwc - TL;DW black hole density
| decreases with increasing radius, and the average density of
| the observable Universe is potentially greater than that of an
| equivalent-sized black hole, so maybe the whole Universe is
| inside one...
| gus_massa wrote:
| No.
|
| I tried looking for more details in
| https://en.wikipedia.org/wiki/Galaxy#Types_and_morphology but
| my conclussion is that it is a complicated topic.
| ycombinatorics wrote:
| old news, happened already 300million years ago
| gigatexal wrote:
| Ahh so we saw the Simulators turn on a black hole in their
| Universe Simulator of which we are NPCs. ;-)
|
| In all actuality this is really really cool.
| ck2 wrote:
| https://crowdmade.com/cdn/shop/files/Dev_Are_Watching_Shirt_...
|
| ( https://www.youtube.com/watch?v=v-aP1J-BdvE )
|
| ( alt https://www.pbs.org/video/what-if-physics-is-not-
| describing-... )
| gigatexal wrote:
| I'm curious if the downvote was calling us all NPCs or the
| entire joke being not funny. I know we all try to be serious
| and contribute to the conversation here but come on it's
| funny, no?!
| spacecadet wrote:
| Hacker news man, least funny place on the internet.
| Incoming down votes.
| _joel wrote:
| https://www.eso.org/public/unitedkingdom/news/eso2409/?lang for
| British English users, sent me to the German page
| ajuc wrote:
| So if I understand correctly the black hole was there already,
| doing nothing, and then some matter was passing near it and
| started falling inside, releasing the surplus energy as radiation
| in the proccess?
| m463 wrote:
| I've always wondered what happens if two black holes run into
| each other? Can previously trapped matter somehow escape?
| ajuc wrote:
| The only way anything "escapes" from black holes is Hawking
| Radiation - virtual pairs of particles that appear and
| disappear constantly - can be split when they happen on event
| horizon - and that slowly drains the energy from black hole.
|
| https://en.wikipedia.org/wiki/Hawking_radiation
|
| If 2 black holes collide - they join together.
| umvi wrote:
| > If 2 black holes collide - they join together.
|
| Presumably though some of the matter "escapes" as energy
| released during the merger, in the form of gravitational
| waves.
| ArnoVW wrote:
| Yes. If memory serves this is the first event that LIGO
| detected. Two black holes of 20-30 solar masses each,
| joining and releasing 1-2 solar masses worth of gravity.
|
| Which resulted in the earth (and space) being stretched
| by less than a fraction of a proton.
|
| And we measured it...
| okanat wrote:
| Interferometers are just magical in their accuracy.
| nomel wrote:
| Merging black holes release more energy than anything
| else in the universe: https://bigthink.com/starts-with-a-
| bang/merging-supermassive...
| newobj wrote:
| What are the odds of being alive and having the technology in
| place to witness any galactic event, on the galactic timescale?
| That's just so wild to me.
| saagarjha wrote:
| Well, the galaxy being big helps ;)
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