LIGO detects most massive black hole merger to date
caltech.edu
caltech.edu
Does this mean that 15 solar masses were converted into energy? Because that's a LOT of energy.
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.
One solar mass is about 2 x 10^30 kg, so round numbers this event released the same as 10^31 Tsar Bombas, which is … a lot of energy? That number is too big to be a good intuition pump.
Let’s try again: over the course of its entire lifetime of about 10 billion years, the sun will release about 0.034% of its mass as energy (2). So one solar mass of energy is about 3000 solar-lifetime-outputs.
So this event has released about as much energy as 45,000 suns over their entire lifetime. I’m not sure how much of the energy was released in the final few seconds of merger, but probably most of it? So… that’s a lot of energy.
And it’s even more astonishing — the supernova at 1 AU would be the same as a billion hydrogen bombs at your eyeball.
Hydrogen bomb yields range from roughly 0.1 MT to 100 MT (the full design yield of the Tsar Bomba), or four orders of magnitude. They can be considered equivalent for the purposes of this comparison. The principle warhead of the US ICBM force, the W87 warhead, has yield of ~0.3 to 0.475 MT.
Even at a distance of several tens of metres from your eye, destructive effects would remain significant.
But in general it's better to have a steady and stable source of power, rather than one enormous burst of energy that you have to spend on something instantly.
[1] https://mastodon.social/@badastro/114852139083587160
[2] https://badastronomy.beehiiv.com/p/the-biggest-black-hole-me...
Just... how? I get what happens with fusion but the numbers are so mind boggling. And it makes what seems like a terrifying ball of fire appear as a space heater in comparison. It's nuts. The GW thing you mention is near incomprehensible to me.
That is, your body is converting mass to energy (the only way the conversion is possible) through chemical processes (ATP-mediated molecular breakdown in the Krebs cycle) at roughly the same rate that the Sun is converting mass to energy through fusion of hydrogen to helium (modulo some pathway hand-waving).
You'll need far more input chemical fuel (carbohydrates and fats, mostly) than the Sun needs of input hydrogen fuel. But the net energy release rate is roughly equivalent.
The biggest difference between you and the Sun is that it (presumably) weighs somewhat more than you do. So that per-unit-mass conversion is multiplied by a much greater mass.
Let me try:
To match this power with sequentially detonated bombs, one would need to set off about 10^13 Tsar Bombas (or one hydrogen bomb scaled up to 5% the mass of the Moon) every second since the Big Bang to match it. With that amount of energy, you could essentially destroy earth every second since the Big Bang.
I'm not sure what happens in black hole merger.. is it an annihilation like event or is just fusion...
If I were to guess before, I think I would have estimated humanity was in the lower 10%. I suppose I was mostly thinking in terms of the Kelvin scale.
It's fascinating to consider how staggering the scale goes in either direction, now. Absolutely bizarre.
(Just planning my next trip.)
I don't think much else would escape the black hole environment.
Tells me a bit darker thing in between the lines - the chance some advanced civilization (or us in far future if we actually survive) traveling FTL by bending space massively is next to zero, we would see (or detect soon) the evidence... unless they do it on planck-level of precision and self-contain all ripples. Nah, it really seems c is the ultimate barrier so far... depressing.
It’s enough “oomph” that we can detect it more than half way across the universe.
"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."
https://www.science.org/content/article/trump-s-proposed-cut...
https://appropriations.house.gov/sites/evo-subsites/republic...
Then again, your file has less drastic reductions on nsf budget so who knows what would be the impact on ligo
Interesting that they break this news today. Props to them for playing the game.
There were also moments dedicated to interviewing a science communicator and the director of the virgo center, and he was, let's say, quite angry at the thought of ligo losing funding. Rightfully so
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?
https://en.wikipedia.org/wiki/Kerr_metric
https://arxiv.org/pdf/0706.0622
https://en.wikipedia.org/wiki/Ergosphere
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.
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-di...
https://www.quora.com/What-is-the-typical-diameter-roughly-o...
It’s wild how much happens in those milliseconds though. Numerical relativity papers like the one you shared from arxiv.org show the horizon “sloshing” before it stabilizes.
If singularities are real...same thing but more boring answer maybe? (the distribution just being: in the center).
Because the whole concept of "shape" assumes properties of space that might not apply inside an event horizon?
You only get an asymmetric black hole during the milliseconds of a merger. And that asymmetry is entirely due to the mass distribution inside the black hole. The black hole only becomes spherical again once the singularities have merged. Or in the more common case of rotating black holes, they only become properly oblate again once their ringularities have merged. Either way it happens quite quickly.
Yeah, that's what I meant. It's hard for me to reconcile the concepts of "the direction of time turns sharply" with "space is just space".
I think that concept might fit with the infinite time dilation preventing a merger from ever actually occurring? I'd be curious how that might differ for matter that's already inside when the critical mass is reached. (I'd also be curious to know all the creative and wacky ways in which I got the above completely wrong given that's just about inevitable.)
What does curvature mean? It means that the direction of time’s arrow is different in different places. To an observer outside of a large gravitational field, events inside the field appear to move more slowly than they would have outside of it. Black holes merely take this to an extreme. To an observer far from a black hole, a clock entering the black hole appears to slow down and finally _stop_ as it crosses the event horizon¹. But simultaneously an observer traveling with the clock observes something different. They see everything outside the black hole slow down and stop instead, while they continue to coast smoothly along. They notice nothing strange at the horizon itself; it is simply empty space with weird visuals in the distance.
This almost seems like a paradox, since the two observers each believe that the other’s clock has stopped. The reason why it’s not a paradox is that the space around the black hole is strongly curved, so strongly that the axis of time swaps place with one direction of space. At the horizon the axis of time flips over and points down into the black hole. The distant observer sees time stop because time is now edge–on, as it were. The observer falling into the black hole notices nothing weird near themselves, because both time and space still exist. Only the images of distant objects show any evidence of curvature. But the falling observer is doomed, for their own time axis now points at the singularity. Their timeline now ends abruptly, while the timeline of the distant observer extends potentially a vigintillion years.
For some edutainment on the subject, I recommend The Science Asylum. He’s done a bunch of videos on gravity and relativity, but here are two in particular:
* Explaining Gravity Using Relativistic Time Dilation <https://www.youtube.com/watch?v=F5PfjsPdBzg&list=PLOVL_fPox2K83_36YgnGisn4rxNvgq1iR&index=7>
* Why Can't You Escape a Black Hole? <https://www.youtube.com/watch?v=yPQUtuTraxs&list=PLOVL_fPox2K-zpTeryROTkmzzsMssSMWp&index=6>
The point where our notions of geometry would break down would be near the singularity, not near the horizon, and we don't even know if a volume enclosed by a horizon (i.e. anything you might call a black hole) necessarily has a singularity inside, it's just that our simple mathematical models all assume one.
It is even the case that once two black holes have overlapping event horizons (so they "touch" in a way) they can't stop touching. So two black holes can zip past one another at a small distance, but if they high-five they can't stop merging.
I think so?
Edit: "The Kerr metric also predicts the existence of an inner and outer event horizon, with the shape of these horizons being oblate rather than perfectly spherical due to the rotation."
From there, I haven't personally done or seen the calculations of the shape of the horizon for Kerr or merging black holes, but my intuition is that it would be indeed peanut shaped for a merger (there are likely some saddle points). The coordinate shape certainly is but you can choose coordinates so that a Schwarzschild black hole is a coordinate peanut so coordinates aren't very meaningful.
In almost all situations it does matter as the collapsing star will behave as it is a black hole. But for the merge of black holes it is significant as it allows to release energy as there is no event horizon.
Because nothing can ever leave the event horizon black holes are essentially perfectly sticky.
No, outgoing gravitational waves could carry out energy and momentum. This is not a closed system. Nobel prize 1993
So, using those relativistic definitions for energy and momentum, I think you're exactly right, at least up to the part about "since the final object is at rest". However:
- As I understand it, invariant mass, aka "rest mass" (which is equivalent to "rest energy", aka "rest mass energy"), is invariant, and it's the same before and after the collision, so the kinetic energy doesn't get "converted into rest mass energy". Rather, if the final object is at rest, then all of its kinetic energy has been radiated away; kinetic energy (E_K) is is total energy (E) minus rest energy (E_0 = mc^2, where m is invariant mass)
- I have no idea whether gravitational waves are the only way for the kinetic energy to be radiated away. I imagine other forms of energy could also be emitted.
- In order to know that the final object is at rest/has no kinetic energy (in an inertial frame), I worry that we might need to have specified more in the original question. In particular, I don't know how to handle spin. (I know that black holes have some concept of "spin", but I don't know if this is like rotational spin, or more like quantum mechanical spin, or something else, and I don't know how it figures into the black holes' total energy.) If we change the original question to say that the black holes are not spinning, then I think we can ignore this (since the collision is head-on).
[1]: https://en.wikipedia.org/wiki/Mass_in_special_relativity#Rel...
To reiterate, I'm not a physicist. I may be off base here, but that's my understanding.
Veritasium recently claimed otherwise https://www.youtube.com/watch?v=lcjdwSY2AzM
If Hawking radiation turns out to be non existent, yes.
Also, we don't know if it's possible to 'crack' open a black hole. If anything, another black hole might be the perfect instrument for doing this.
Black Hole brand adhesive: when you absolutely, positively need something stuck down for eternity.
Would they still fully merge, or might you get a mass exchange between them? Or even a smaller black hole spun off?
But this is because of a distinction between the Apparent Horizon [1] (which is coordinate-dependent) and the true global event horizon. So they appear to briefly merge but no true global event horizon forms to encompass both. I think!
[1] https://physics.stackexchange.com/questions/38721/what-is-th...
So black holes cannot approach each other faster than the speed of light. And if their trajectories intersect perfectly, they won’t be able to escape each other’s gravity.
A black hole can’t pass “through” another black hole like two bullets hitting each other. More like two incredibly strong magnets hitting each other in midair.
When we imagine flying "at nearly the speed of light" towards something thats traveling the same speed towards you, we tend to imagine a collision at high speeds.
But for blackholes that turn space into time and time into space, they can see the other blackhole slowing to a complete stop as its about to touch. Or it can look differently, it all depends on the position and speed of an observer.
We cant even agree on the basics like: "It doesnt matter how it looks, but they must collide", since if we look at something falling into a blackhole (which I pressume could be another blackhole just as well), we see it slow towards 0 at the edge and fade away in redshift instead of seeing it actually fall trough.
Its just all very weird and unintuitive stuff.
(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 ?")
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.
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"
Maybe it should!
There's so many technologies that we use today that derive from astronomy, space exploration and similar. We don't do a good job making that point to folks.
We still need fusion reactors, flying cars, telepathy and a cure for cancer yesteryear.
Instead we had 140 characters, PFAS in everything (which make the cure for cancer even more overdue) ; cars that got very much not flying but very bigger (and made the world hotter, and the fusion even more overdue) ; smartphone that makes spreading lies faster than even telepathy could ever do, etc...
But, now, sure, our flying drones are guided with "A", so the authoritarian régimes only have to point in a vague direction to get innocent people bombed.
No wonder "Yay, science" is getting a hard rep.
Thank the FSM you Americans decided to stop doing science altogether. Maybe the world needs to see that "bad research" is worse than "no research at all".
Last time we did that in Europe, it only lasted for 1000 years, and got us cool looking castles and dramatic paintings. So, art, I guess ?
You should think of some research in similar ways. This is us saying, look how rich and powerful we are, we can devote a significant part of our society's productivity on discovering the very essence of this universe with no practical benefit to us. Detecting blackhole mergers is an intellectual monument.
We don't know.
However, black holes are close to the limit of our scientific knowledge. We don't know what happens on the other side of an event horizon (and we may never know, at least not experimentally). Learning more about them means learning more about the universe, and every once in a while we make a breakthrough that leapfrogs our technology. There's nothing else that we can do with so much potential.
Most of the time though, the progress is quite 'boring', at least if you are not in a related field.
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.
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?
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?
Your disk will emit a lot of gravitational on electromagnetic radiation, and after a while it will be a nice sphere. (Unless it's rotating and it will be a nice somewhat-elipsoidal ball.)
---
> and then an electron popped into existence due to quantum randomness
I feel there is a huge can of worms of technical problems in this sentence that nobody know how to solve for now. Just in case replace the quantum randomness with a moron with a broken CRT used as an electron cannon.
Time doesn't exist for black holes, so "after a while" is not something you can say about them.
I'm not sure if we can measure the shape of black holes, but I'm sure everyone think they are spheres with a slight deformation due to rotation.
Event horizons are non-physical. Better to think of it as "then a spherical event horizon would become apparent." When the mass within a given black-hole-shaped volume (spherical for non-rotating mass) is "one electron short" of being a black hole, then one can define a surface in the shape of the (future) black hole where the escape velocity is /just/ below the speed of light. In practice, all light emitted within that volume will already be captured by the mass, unless it's perfectly perpendicular to the (future) event horizon. When that extra electron is added, it becomes true that the escape velocity at that same surface is now the speed of light -- the definition of event horizon. But nothing needs to "form" to make this true.
> a sphere instantly
The concept of instantly doesn't work with time dilation like this. What you see will be different depending on if you are also falling in, or if you are far away.
Perhaps if it were exceptionally wide the whole disc wouldn't collapse. Maybe only the parts near it's center. In that case you'd end up with a large ring around a neutron star. Add a bit more mass and maybe it's now a ring around a black hole. The gravity of the ring might distort the event horizon in some way, I'm not sure quite how, but probably its possible to get a non-spherical hole in situations where the objects distorting the shape are still in the universe.
But as for the matter lost into the hole, it's gone. If the hole were to retain some shape based on what's "inside" of it, that would be the kind of information leak that the laws of physics do not permit.
The event horizon is the imaginary line across the river which once passed, even if you paddle as quickly as you can, you won't be able to get away from the waterfall. Once you pass that line, you're bound to reach the waterfall eventually.
Now, thanks to Maxwell and Einstein, we know there's a maximum speed that anyone can paddle, the speed of light, and so we define the event horizon to be relative to this speed.
You can calculate the event horizon for just about anything. The main difference between a black hole and everything else, is that for a black hole the event horizon is larger than the object itself.
For example, the event horizon of a neutron star with a mass of 1.4 solar masses and a radius of 10km is about 4.1 km, well inside the neutron star. Thus you don't get the "black hole effect", since once you pass the surface of the neutron star the matter above you pulls you away from the center.
The river analogy is actually not far off what they try to use as an analog for testing black hole predictions, effectively a large water tank with a drain hole. Sixty Symbols did a video on this way back[1], and this thesis[2] goes into the details. Some are going beyond water using liquid helium to simulate quantum black holes this way[3].
[1]: https://www.youtube.com/watch?v=kOnoYQchHFw
My guess is that in some popular depictions black holes are like holes, and things fall in the holes, and even a small black hole can possible fall inside a bigger hole.
A better image is too drops of water on a glass, add some black ink for bonus realism. They merge into a bigger drop. Except, obviously black holes are not filled with water. And the "average density" of the new black hole is smaller then the "average density" of both original black holes, unlike the density of water drops on a glass. So don't take this image too literaly.
(There are some problems to define the "density" of a black hole, but let's ignore all of them.)
Mass and energy.
But that leaves us with black holes forming inside a black hole, which I have absolutely no idea what to do with.
Can't we generalize to say that we observe that black holes have a similar density (which is to say, proportion of mass to volume) any sample of the observable universe sufficiently large as to be roughly uniform?
In other words, doesn't this observation scale both down (to parts of the universe) and up (beyond the cosmological horizon, presuming that the rough uniformity in density persists), at least for any universe measured in euclidian terms?
It's very possible that I'm wrong here, and I'd love to be corrected.
...I also think we have to acknowledge that "similarly" is doing a fair bit of work here, as we're not accounting for rate of expansion - is that correct?
I confess I just ... take it for granted in this kind of context that "mass" or "energy" or "mass+energy" all mean the same thing. Someone who wants to refer just to the total amount of matter will say something like "the total mass of the matter in the universe".
It's commonplace for physicists to write just "mass" when talking about this sort of thing. E.g.,
P T Landsberg, "Mass scales and the cosmological coincidences", Annalen der Physik, https://onlinelibrary.wiley.com/doi/10.1002/andp.19844960203:
"Theories involving the parameters h, c, G, H (in a usual notation) are considered. A huge ratio of 10^120 of the mass of the universe (m_u) to the smallest determinable mass m_0 in the period since the big bang occurs in such theories."
(Not cherry-picked; I went to the Wikipedia article on "Black hole cosmology", noted that it just says "mass" rather than "mass-energy" or whatever, and followed the link in the attached footnote. Also, so far as I know, not crankery; Landsberg was an eminent physicist.)
Which part of them is barely not touching?
Or in other words, black holes mergers conserve their total radius, not volume as one would get with normal matter.
They actually convert up to 42% of their mass into energy, mostly radiation
From our point of view nothing can actually fall into a black hole, instead it time dilates into nothing. "It is true that objects that encounter the event horizon of a black hole would appear “frozen” in time"[1]
So we would never actually see the black holes merge. In fact I'm not clear how a black hole can even form in the first place, since it would take an infinite amount of time to do so (again, from our POV).
(And yes, I know that from the POV of the falling object, they just fall in like normal. But that doesn't help us, because we'll never see it.)
[1] https://public.nrao.edu/ask/does-an-observer-see-objects-fro...
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
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_Ant...
https://www.esa.int/Science_Exploration/Space_Science/LISA/C...
Both LISA and LIGO II were deleted from the last Congressional budget
https://bigthink.com/starts-with-a-bang/ligo-heaviest-black-...
Was the budget cut in the BBB passage last week?
But then I use the voice of Djimon Hounsou and the quote from the Gladiator "but not just yet".