Black hole orbital mechanics
April 29, 2020 1:28 AM   Subscribe

"The OJ 287 galaxy hosts one of the largest black holes ever found - over 18 billion times the mass of our Sun. Orbiting this behemoth is another black hole with about 150 million times the Sun's mass. Twice every 12 years, the smaller black hole crashes through the enormous disk of gas surrounding its larger companion, creating a flash of light brighter than a trillion stars - brighter, even, than the entire Milky Way galaxy. The light takes 3.5 billion years to reach Earth." Researchers are able to both predict and see this flash of light (NASA Press Release) (Here’s a video)

Because of the irregular orbit, the black hole collides with the disk at different times during each 12-year orbit….
..in 2018, a group of scientists led by Lankeswar Dey, a graduate student at the Tata Institute of Fundamental Research in Mumbai, India, published a paper with an even more detailed model they claimed would be able to predict the timing of future flares to within four hours... those scientists report that their accurate prediction of a flare that occurred on July 31, 2019, confirms the model is correct.
These multi-epoch Spitzer observations provide a parametric constraint on the celebrated BH no-hair theorem since the researchers assumed the perfect symmetry of the black holes
posted by vacapinta (17 comments total) 34 users marked this as a favorite
 
The Wikipedia page for OJ287 says that the two black holes are expected to merge in about 10,000 years. Now that’s going to be a signal for a future gravitiational wave detector to pick up.
posted by pharm at 2:15 AM on April 29, 2020 [3 favorites]


Space is just showing off again, trying to impress physicists.
posted by GenjiandProust at 7:35 AM on April 29, 2020 [1 favorite]


That 4 hour margin prediction is crazy! What an impressive feat. Thanks for the post.
posted by dhruva at 7:37 AM on April 29, 2020 [2 favorites]


I often post snark at cool science, but this time I have nothing to say. This is entirely awesome.
posted by Joe in Australia at 8:43 AM on April 29, 2020 [1 favorite]


So how did they get that dope GoPro video? Sick.
posted by misterpatrick at 8:58 AM on April 29, 2020


Super cool. So asking the obvious questions for us interested but completely novice readers.

I assume this wouldn't be visible from earth by us mere-mortals if they can accurately predict the next cycle? (I know from the article that the last one was when the OJ 287 galaxy was on the other side of the Sun from us etc - but assuming it just happens to be in the right part of the sky at the right time around 2031 etc). I mean it sounds like a colossal flash but it's also 3.5 billion light years away and wasn't sure if it is in visible wavelengths etc. Looks like OJ 287 has an apparent magnitude of 15.43 which I think if I'm reading right means there is no chance even the "quadrupling of its brightness" would make it visible except with fairly large telescopes.
posted by inflatablekiwi at 10:21 AM on April 29, 2020


So this is that sacred lotus I have heard so much about? Every 3.5 billion years, just in time for our birthday? Science blinds me to all but the cracks I slip through, so easy in this little pond.
posted by Oyéah at 10:59 AM on April 29, 2020 [1 favorite]


this light, will it blind me with science?
posted by clavdivs at 12:45 PM on April 29, 2020 [2 favorites]


6 is about the dimmest magnitude visible to the naked eye. It’s a reverse logarithmic scale, so 15.43 is WAY dimmer. (For comparison, Sirius, the brightest star in the sky, has a magnitude of -1.46, the sun, -22) I just looked it up...to see this with the naked eye, you will need a telescope with at least a 10 inch diameter.
posted by sexyrobot at 1:00 PM on April 29, 2020 [2 favorites]


So this is the precession of the perihelion of the orbit of Mercury writ large, right?

And the plane of the orbit must be tilted with respect to the disk surrounding the black hole and is pretty eccentric, so as the orbit precesses, it would be cut by the disk at very different points with respect to the apo- and peri- points, and that must complicate calculating the timing of the flashes quite a bit.

Plus, the average interval will get shorter and shorter as it spirals in.

And is this the scenario, where the angular momentum of two merging black holes points in different directions, resulting in asymmetric emission of gravitational waves, the back reaction from which could eject the merged black hole at speed into extra-galactic space??
posted by jamjam at 2:27 PM on April 29, 2020


Thanks for the explanation sexyrobot - so, paraphrasing, you're saying we'll need a telescope hung like a sexytelescopehorse to see it.
posted by inflatablekiwi at 2:37 PM on April 29, 2020 [1 favorite]


Lol...and that’s just the diameter! Still...if you really want to see it we should break out the big boy. (Oh I want it so bad)
posted by sexyrobot at 4:23 PM on April 29, 2020


"The Wikipedia page for OJ287 says that the two black holes are expected to merge in about 10,000 years."

But what will be around in 3.5 billion years to watch it from here?
posted by Evilspork at 7:05 PM on April 29, 2020


I think what they are saying is that it has probably already happened about 3,499,990,000 years ago.
posted by Hairy Lobster at 10:38 PM on April 29, 2020 [1 favorite]


English is not really built for high spacetime interval relationships. I prefer to think of this as something that will happen 3,499,990,000 years ago.
posted by flabdablet at 11:16 PM on April 29, 2020 [5 favorites]


The things you can do with a spirograph!
posted by boilermonster at 11:30 PM on April 29, 2020 [2 favorites]


English is not really built for high spacetime interval relationships

Let me quote the relevant bit from the Hitchhiker's Guide to the Galaxy


The major problem is quite simply one of grammar, and the main work to consult in this matter is Dr Dan Streetmentioner's Time Traveller's Handbook of 1001 Tense Formations. It will tell you for instance how to describe something that was about to happen to you in the past before you avoided it by time-jumping forward two days in order to avoid it. The event will be described differently according to whether you are talking about it from the standpoint of your own natural time, from a time in the further future, or a time in the further past and is further complicated by the possibility of conducting conversations whilst you are actually travelling from one time to another with the intention of becoming your own father or mother.

Most readers get as far as the Future Semi-Conditionally Modified Subinverted Plagal Past Subjunctive Intentional before giving up: and in fact in later editions of the book all the pages beyond this point have been left blank to save on printing costs.
posted by DreamerFi at 6:53 AM on April 30, 2020 [4 favorites]


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