10 ms·
LIGO detects most massive black hole merger to date
- ChrisArchitect 1y ago[dupe] https://news.ycombinator.com/item?id=44555220 https://news.ycombinator.com/item?id=44555220
- cloudrkt 1y agoI wonder how the singularities would merge with each other.
- Enginerrrd 1y agoWe can't REALLY answer questions about what's inside the event horizon, but some real work has been done on what BH mergers look like, though even that as I understand, is extremely difficult model. https://m.youtube.com/watch?v=5AkT4bPk-00 https://m.youtube.com/watch?v=5AkT4bPk-00
- TechDebtDevin 1y agoWhat are the waves of gradient colors, gravity?
- 20k 1y agoI'd guess its the weyl scalar w4, which is generally used to extract gravitational waves
- 20k 1y agoThese kinds of simulations inherently cannot model the singularity accurately whatsoever. At the singularity, the numerical technique used becomes knowingly invalid In fact, the entire interior of the event horizon is actually physically invalid in these simulations. The formalisms used trap the errors inside the event horizon, as the errors turn out to be strictly causal. And because of that, theoretically they can't escape Of course that analysis breaks down in the face of discretisation, so errors tend to leak out a bit under low resolutions, so you have to handle things pretty careful. Either way, you shouldn't draw any conclusions about the interior Source: I've done a lot of these simulations
- perdomon 1y agoWhat happens when black holes collide? Does one black hole “consume” the other? Do they become a larger black hole? Does it get more dense or just larger?
- chasil 1y agoWhat happens inside cannot be known. As I understand it, black holes are defined by three quantities: mass, spin, and charge. I'm assuming that these quantities will be additive post-merger. Edit: "The black holes appear to be spinning very rapidly—near the limit allowed by Einstein's theory of general relativity." Perhaps the additive spin becomes asymptotic. Alternately, the gravitational waves might have departed with the energy of the excess spin.
- jameskilton 1y agoMy basic understanding is that they combine, basically you just add the masses together. That increased mass then means more gravity, so the event horizon is pushed further out.
- __MatrixMan__ 1y agoThey become a more massive one. The volume of a black hole (assuming you're measuring at the event horizon) is determined only by its mass, so the final density is the same as you'd get for any other black hole of that mass regardless of how it came to be. I don't know how to address the "consume" question. If you were pulling on a piece of fabric and two tears in it grew until they met each other to become one tear... would you say that the larger one consumed the smaller?
- a012 1y agoI think the GP meant “merge”
- dataflow 1y ago> The volume of a black hole (assuming you're measuring at the event horizon) is determined only by its mass, so the final density is the same as you'd get for any other black hole of that mass regardless of how it came to be. Wait, really? So if you had a super massive disk that was just 1 electron away from having enough mass to become a black hole... and then an electron popped into existence due to quantum randomness... then it would become a sphere instantly? Wouldn't that violate the speed of light or something?
- MattPalmer1086 1y agoI wonder what would happen if one black hole shot through another one at high relativistic velocity, instead of spiralling towards one another.
- fsmv 1y agoThey would merge and produce a black hole with the sum of their momentums Because nothing can ever leave the event horizon black holes are essentially perfectly sticky.
- mkw5053 1y agoSo, if two black holes, each with mass M, were moving at nearly the speed of light and collided head-on (resulting in a final velocity of zero), what would happen to all that momentum? Would the resulting black hole have a mass greater than 2M? If so, how and why would this occur?
- mkw5053 1y agoI think I'm going to answer my own question by saying both momentum and energy are conserved. The momentum of the entire system was zero before and after the collision. Energy must also be conserved, and since the final object is at rest, all the kinetic energy gets converted into rest mass energy, minus what is radiated away as gravitational waves.
- photon_lines 1y agoCorrect. If you're curious about the 'essence' of what black holes are I actually just did a write-up on them which you can find here: https://photonlines.substack.com/p/an-intuitive-guide-to-black-holes https://photonlines.substack.com/p/an-intuitive-guide-to-bla...
- lkuty 1y agoThanks. Little typo "Let’s inflate Earth once again to its regular size and see what impact placing a 10 kg weight on it has." Should be 1kg.
- jimnotgym 1y ago[flagged]
- deleted 1y ago[deleted]
- mnemonk 1y agoMan, that is some seriously interesting phenomena: "The black holes appear to be spinning very rapidly—near the limit allowed by Einstein's theory of general relativity," explains Charlie Hoy of the University of Portsmouth and a member of the LVK. "That makes the signal difficult to model and interpret. It's an excellent case study for pushing forward the development of our theoretical tools."
- veunes 1y agoIt's like nature handed us a stress test for general relativity
- amelius 1y agoDoes the spinning of a spherical object cause any gravitational waves?
- NL807 1y agoThe rotating mass drags space time around it, called frame dragging, which is different from gravitational waves. Gravitational waves consists of oscillations, which is caused by change of mass, wobbling of spinning objects, or several masses orbiting around a barycentre.
- WrongOnInternet 1y ago> the 225-solar-mass black hole was created by the coalescence of black holes each approximately 100 and 140 times the mass of the Sun. Does this mean that 15 solar masses were converted into energy? Because that's a LOT of energy.
- andrepd 1y agoYes! And still, gravity is so weak that that immense amount of energy translates to just a relative contraction of less than 10^-20, or about a hair's width in the distance from the Earth to the Moon.
- cgdl 1y agoDo we know how far this event was from earth? Wouldn't that distance be the determiner of what the relative contraction observed on earth would be?
- sgustard 1y agoestimated distance of 2.2 Gpc per https://en.wikipedia.org/wiki/GW231123 https://en.wikipedia.org/wiki/GW231123
- irjustin 1y agoThat's how fast the millennium falcon goes
- BurningFrog 1y agoThat's 7.2 billion light years. More than halfway to the most distant galaxy the Webb telescope has found. So this event happened 7.2 billion years ago. There is no mention of in which direction. Maybe the triangulation wasn't working at the time. You need three LIGOs for that.
- UltraSane 1y agoAt 10 times the Schwarzschild radius Space literally stretches and contracts by 10-100%
- BurningFrog 1y agoI've always thought the event horizon for a black hole has to be spherical. But my physics intuition tells me that as two of them merge, the resulting BH should have a "peanut" shape, at least initially. And maybe it can keep having an irregular shape, depending on the mass distribution inside it?
- itishappy 1y agoIt's only spherical in a Schwarzschild (non-rotating) black hole. A rotating black hole is called a Kerr black hole, and stuff gets weird, such as there being an oblate event horizon, a weird outer horizon called an ergosphere where spacetime gets dragged along such that it's impossible to stand still and you can accelerate objects using the black hole, a weirder inner horizon called the Cauchy horizon where time travel is possible, and a singularity in the shape of a ring. Your intuition is correct that during a merger it would be weirder still. https://en.wikipedia.org/wiki/Kerr_metric https://en.wikipedia.org/wiki/Kerr_metric https://arxiv.org/pdf/0706.0622 https://arxiv.org/pdf/0706.0622 https://en.wikipedia.org/wiki/Ergosphere https://en.wikipedia.org/wiki/Ergosphere https://en.wikipedia.org/wiki/Cauchy_horizon https://en.wikipedia.org/wiki/Cauchy_horizon Edit: Updated the bit about about horizons as I research a bit more. It's complicated, and I'm still not positive I have it exactly right, but I think it's now as good as I can get it.
- AnimalMuppet 1y agoCould you (or anyone) tell what the radius of the ring singularity is, in terms of mass and angular momentum? I haven't been able to find that.
- itishappy 1y agoThe math seems to suggest R=a, or simply the spin in terms of length. It's certainly an oversimplification, as the answer will depend on the choice of metric. Here's the best resources I've been able to find on the question. Roy Kerr himself responded to the Quora question: > There is no Newtonian singularity at the Center of the earth and there is no singularity inside a rotating black hole. The ring singularity is imaginary. It only exists in my solution because it contains no actual matter. When a star collapses into a black hole it keeps shrinking until the centrifugal force stabilizes it. The event shell forms between the star and the outside. In 57 years no one has actually proved that a singularity forms inside, and that includes Penrose. instead, he proved that there is a light ray of finite affine length. This follows from the “hairy ball theorem”. The stack overflow answer seems to describe the problem in terms I can better understand: > It seems unlikely to me that you're going to be able to formulate a notion of diameter that makes sense here. Putting aside all questions of the metric's misbehavior at the ring singularity, there is the question of what spacelike path you want to integrate along. For the notion of a diameter to make sense, there would have to be some preferred path. Outside the horizon of a Schwarzschild black hole, we have a preferred stationary observer at any given point, and therefore there is a preferred radial direction that is orthogonal to that observer's world-line. But this doesn't work here. https://physics.stackexchange.com/questions/471419/metric-diameter-of-a-ring-singularity https://physics.stackexchange.com/questions/471419/metric-di... https://www.quora.com/What-is-the-typical-diameter-roughly-of-the-ring-singularity-at-the-center-of-a-rotating-supermassive-black-hole https://www.quora.com/What-is-the-typical-diameter-roughly-o...
- kens 1y agoA month ago, the proposed NSF budget would shut down one of the two LIGO observatories in the US, wrecking its ability to triangulate the location of events such as this black hole merger. A shutdown would also severely damage the noise margins and detection rate. Does anyone know if the shutdown is still planned? (I couldn't find any recent info.) https://www.science.org/content/article/trump-s-proposed-cut-giant-physics-experiment-could-snuff-out-new-form-astronomy https://www.science.org/content/article/trump-s-proposed-cut...
- ac794 1y agoI believe the proposed budget is being marked up tomorrow (July 15th, 12:00). Currently the NSF budget is set to be ~$7 billion, a 23% cut compared to FY2025. I'm not sure how this affects LIGO exactly. https://appropriations.house.gov/sites/evo-subsites/republicans-appropriations.house.gov/files/evo-media-document/fy26-commerce%2C-justice%2C-science%2C-and-related-agencies-bill-summary-subcommittee.pdf https://appropriations.house.gov/sites/evo-subsites/republic...
- amarcheschi 1y agoI had read something less recent than what you posted, but in that is said about 40% of ligo funding would be cut https://www.science.org/content/article/trump-s-proposed-cut-giant-physics-experiment-could-snuff-out-new-form-astronomy https://www.science.org/content/article/trump-s-proposed-cut... Then again, your file has less drastic reductions on nsf budget so who knows what would be the impact on ligo
- bee_rider 1y agoI wonder why Bezos doesn’t just pick up the tab, he likes space, right?
- jedberg 1y ago> I believe the proposed budget is being marked up tomorrow (July 15th, 12:00) Interesting that they break this news today. Props to them for playing the game.
- iataiatax10 1y ago[flagged]
- biggusdickus69 1y ago[flagged]
- HocusLocus 1y agoChirps or it didn't happen
- HenryBemis 1y agoWhen I read 'news' like that, I 'compare' myself to the thing. And then I think how this 'thing' can swallow me, everyone around me, everything as far as the eye can see (thank you light pollution, we can only see the moon and perhaps 5-6 more 'things' out there (ffs!)) and then we will be 'no more'. But then I use the voice of Djimon Hounsou and the quote from the Gladiator "but not just yet".
- croemer 1y agoBoring press release without any real details. I wish the paper would trend not an empty press release announcing the announcement.
- veunes 1y agoKind of amazing that LIGO/Virgo/KAGRA can even detect and decode something that extreme
- ck2 1y agoeven the "sound" is spooky https://www.youtube.com/embed/QyDcTbR-kEA https://www.youtube.com/embed/QyDcTbR-kEA
- jcims 1y agoIn case it's not clear, that 'chirp' is exactly what we would hear if the merger was powerful enough to actually be detectable by our ears. It's the vibration induced in the final moments and the frequency is the speed at which the blackholes are orbiting each other before they merge. Things the size of multiples of our Sun dancing around each other a thousand times per second. It's insane to me.
- ck2 1y agoso I hate to have to ask this but must is the space version of LIGO, known as LISA (and will be far more sensitive) now doomed? because of the "savings" by DOGE? https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Antenna https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Ant...
- pantalaimon 1y agoThis is a project by ESA, it's not affected by DOGE https://www.esa.int/Science_Exploration/Space_Science/LISA/Construction_of_ESA_s_ambitious_LISA_mission_begins https://www.esa.int/Science_Exploration/Space_Science/LISA/C...
- ck2 1y agoLISA is (was?) listed as a joint NASA-ESA project Both LISA and LIGO II were deleted from the last Congressional budget https://lisa.nasa.gov/ https://lisa.nasa.gov/ https://bigthink.com/starts-with-a-bang/ligo-heaviest-black-hole/ https://bigthink.com/starts-with-a-bang/ligo-heaviest-black-...
- m3kw9 1y agoEverything in the universe is massive because we are just so small. Everywhere but within the confines of our solar system, calling something massive is a meaningless endeavour, it’s so big nobody has any idea how to appreciate it, and then there is always going to be something bigger which makes that black hole look tiny
- phtrivier 1y agoI'm in dire need of good news, so help me see it in an optimistic lens: can you imagine a path (even very indirect) where this kind of discovery ends up having a practical use that makes real life better here on Earth ? (I'm not in the age-old debate about "is research useful ?" - I agree the answer is yes ; I just have a failure of imagination that prevents me from answer the question "how is this research going to be useful in the long run ?")
- beng-nl 1y agoJust an amateur interested person here, but I think there is something very positive about these developments. There are probably more, that experts can chime in on, but one I know about is that gravitational waves can give us a signal of what happened when the universe came into existence. The cosmic microwave background radiation (CMB) is a similar thing with photons - it is a signal from the earliest photons to be emitted after the Big Bang / inflation. But the universe was opaque to photons for the first 300000 or so years. Even so cosmological theories have been confirmed and falsified based on this data. But gravitational waves are signals that originated right from the start, and are not blocked by anything unlike photons, and so likely give us much clearer information on the state of the universe when it was created. This might make new insights in fundamental physics possible (quantum mechanics, relativity). This overlaps with the fascinating topic of multi-messenger astronomy: observing an event using photons, neutrinos, and now: gravitational waves, leading to triple-messenger astronomy, leading to (hand waves) more insights than.. otherwise. How this might make real life better ln earth: that is a gamble, but progress in fundamental physics has frequently made life better on earth. I wish you All the best in feeling better about the world.
- NooneAtAll3 1y ago>practical< usefulness of this type of research isn't results per se - but methods of getting to them LIGO needs extremely precise lasers, stationary platforms, extreme positioning precision, tons of supporting software - even if things "exist", the _need_ for results provide advances and improvements astronomy itself already gave us cmos sensors (aka digital cameras) - but using your phone camera doesn't really make you think "this is caused by distance measurement to the stars"
- favflam 1y agoWhat is the budget outlook for LIGO? Was the budget cut in the BBB passage last week?