Imminent merger of a supermassive black hole binary
arxiv.org
arxiv.org
Between 100 days and 3 years we will record what will be the single largest energy release we have ever recorded.
To give an idea of our records so far: our detection of black hole mergers around the 100-150 solar masses scale are just behind a couple gamma ray bursts as the single largest energy release ever.
How big are the black hole mergers around 150 solar masses and the two largest gamma ray bursts?
The energy release converted the mass of between 1-6 solar masses into energy.
With black hole mergers this energy release/conversion is in the form of gravitational waves that we then detect!
So imagine the sun, times 6, every atom, converted into that energy. That’s what we have already recorded.
This predicted one is not even in the same ballpark. Those 1-6 sun matter into energy conversions are ants compared to what’s coming.
These supermassive black holes are thousands to tens of thousands of times the mass of our sun. (Not sure if the ones in this paper are in the billion solar masses class. Yes they do exist)
This event will convert the mass of perhaps a hundred or a thousand suns worth of matter into energy in an instant. (Not sure if the paper gives any accurate predictions I’m lazy!)
FWIW, these gravitational waves are too low in frequency for LIGO to catch. The paper says it would be within detection range of LISA (the ESA's space-based laser interferometer), but unfortunately they haven't launched that yet.
However, there's a related effect that could be measurable some 5-10 years afterwards:
>"They should, however, leave an imprint on spacetime itself, a sort of relaxation of distance and time dubbed gravitational wave memory, which could be detected over many years by monitoring the metronomic pulses of spinning stellar remnants known as pulsars. “It’s a very tricky signal to measure,” Ransom says, “but that would be definitive, a total smoking gun” of merging supermassive black holes."
https://www.science.org/content/article/crash-titans-imminen...
I wonder if this predicted supermassive black hole merger is rare for us - once in a lifetime, or we find out after LISA is operational that they happened frequently.
Am I right in thinking that the search area something like LISA and LIGO "see" is essentially the entire observable universe?
Could we could catch a merger from the first billion or so years of the universe?
This video has answers to your questions.
Edit: Looks like a great channel overall.
Will this be true throughout the collision? The ones we've recorded have a sort of 'chirp' right before the merge.
This has to be a really rare occurrence. Hopefully, it won’t be behind the sun when it coalesces, though that won’t hide the gravitational effects, of course.
You say insane, these guys say, "no, perfectly sane and expected. We have a model predicting it."
But I know what you actually meant! ;-)
The universe is close to 14 Billion years old. 1:10,000 is like nothing to the universe. There are several orders of magnitude stars in the universe that you could have 1:10,000 events occur daily. You as a member of the very johnny come lately human species (in terms of the universe's age) might feel like 1:10,000 seems high.
I mean, I support scratching this particular lottery ticket, because unlike lottery whose reward (money) is fungible, if it pays off we will get information we won't get any other way. But we shouldn't expect to win, that's all I am saying.
if the odds of this kind of merger are 1:10,000 years, we only get 1 "play" every year.
Time and space are intertwined. So if the light hasn't arrived yet, has reality really arrived yet?
You could say "it's already happened" as a first approximation but this isn't really true because the statement implicitly assumes there is some kind of universal "now" that can be used as a reference point for timing things.
No such universal "now" exists. That's why the question "What's happening right now on Mars?" makes no physical sense. "Now" is a function of both when and where you're standing.
The question "What's happening right now on the other side of my living room?" also doesn't make any physical sense. But the difference between reality and our perception of it is less easily detectable in that case.
The only wrinkle in the scenario of a distant galaxy is cosmic expansion inducing a different reference frame by causing motion relative to Earth. However, if the redshift isn't more than a few percent then the time dilation won't be either, so we can be pretty sure it will be in the past by any definition that isn't moving a fair fraction of c relative to us.
Don't confuse light travel time with relative simultaneity. Relativity does weird things to time but that's not one of them.
I agree that a reference frame that has about the same velocity as the stuff you care about is in some sense privileged. But the fact that we haven't seen the merger happen yet means that it's outside our light cone, which means there exists a reference frame where the merger hasn't happened yet.
that is to say, t_{this_coversation} < t_{merger}, in that frame.
As for timing of distant events, GP didn't make any reference to other reference frames at arbitrary velocity, only different positions. In our reference frame, which they were implicitly talking about, the merger (assuming the prediction is correct) was in the past, unambiguously.
So let's say you're a GPS satellite. GR says your clock ticks too fast because you're farther from the center of the earth's gravity well than the wristwatches of people on the surface.
But SR says your clock ticks slower than a wristwatch on the surface because you're whizzing through space at ~15,000 km/hour.
Which is right? Both. And they do not exactly cancel each other out (in general). So both GR and SR have to be taken into account to make GPS satellites produce accurate locations and times.
If clock A runs at 1x speed and clock B runs at 2x speed.
Now will refer to time t for clock A and t / 2 for clock B.
What's the problem? We can still have a now defined as I mentioned above. t1=t2=0 at the start. Now when t1=x for place A will refer to when t2=2*t1 at place B.
https://en.wikipedia.org/wiki/Relativity_of_simultaneity
Also, from https://en.wikipedia.org/wiki/Spacetime
"the distances and even temporal ordering of pairs of events change when measured in different inertial frames of reference (this is the relativity of simultaneity); and the linear additivity of velocities no longer holds true."
I'm not saying to use different frames of reference. I am saying to use a single universal frame of reference.
The lander wasn't in paused motion so that everything times out with us on Earth. Same concept with deep space objects. What we see is the information as it was when it left. To see what happened just now, we'll have to wait another few million years.
I shouldn’t read too much about relativity before my morning coffee.
The more you know.
The most striking demonstration of this effect is what happens around the photon sphere (3/2 the radius of the event horizon of a non-rotating black hole. The orbital velocity at this radius is the speed of light. Consider the two body problem, of a single mass interacting gravitationally with the black hole. If this mass crosses the photon sphere from the outside, it will inevitably spiral into the event horizon. If the mass crosses the photon sphere from the inside, it will either escape to infinity proceed to cross it again from the outside (and subsequently spiral into the event horizon).
The more general phenomena is orbital decay that happens in any 2 body problem under general relativity. From a conservation of energy standpoint, the massive amounts of energy contained within gravitational waves come from the release of gravitational potential energy as the two orbiting objects fall towards each other.
The more questions you have ;-)
https://www.science.org/content/article/crash-titans-imminen...
It's funny to see the competitive nature between groups.
The one thing I took from this article though was that the instrument we have built specifcally to detect gravitational waves won't even be effective for this level of event as it is "tuned" for different type of events.
Gravity wave detectors are sensitive to ranges of frequencies, just as electromagnetic wave detectors are. For instance, LIGO is sensitive to gravity waves in the range of 7kHz down to 30Hz. The gravity waves from this merger would be at far lower frequencies/longer wavelengths.
Read “Einstein’s Shadow”by Seth Fletcher.
It’s a current book about the attempt to image a black hole.
I wonder what means an event like this for good part of the galaxy where it happens.
its scary to even imagine a disaster of this scale
"I've lived next to this volcano/merging black holes for my entire life, as my family before me. Nothing has ever happened." Until it does.
https://astro.ucla.edu/~wright/CosmoCalc.html says this galaxy is ~1.1 Gly, so "not exactly close" whatever that means on a cosmic scale. Intriguingly, this event took place when life on Earth barely existed at all...
Edit: at 1,5x10¹¹ solar masses, the galaxy is not at all small (and neither are the BH involved!!!) it's in the same ballpark of the Milky Way.
1.2 bn light years sounds like safe distance ..is it?
The opposite of HFT is ULFT: stock trading on a gigayear timescale outliving the typical planetary civilization. Its biggest enemy is inflation -- meaning cosmological inflation, that nasty phenomenon tearing the universe apart and doing a number on intergalactic shipping indices. To quote an extremely recent earthling philosopher: intergalactic trade grows strong when elderly hominids plant {untranslatable #32} in whose {untranslatable #993} they know they shall never {untranslatable #440}.