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27 points DaveZale | 1 comments | | HN request time: 0.208s | source
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pavel_lishin ◴[] No.45569161[source]
> The existence of two black holes in OJ287 was first suggested in 1982. Aimo Sillanpää, then a graduate student at the University of Turku, observed that the brightness of the quasar changed regularly over a 12-year cycle.

Damn, that's about the time it takes Jupiter to orbit the sun. That feels wildly close together for objects that mass 18 billion & 150 million times that of our own sun.

These black holes (according to a calculator I found online) have radii of 53 billion km and 400 million km, so I'm guessing they must be orbiting significantly further away, and significantly faster than Jupiter (which is ~800 million km away from the sun) - which makes sense, given the monstrous 18b figure. I wonder how far apart they are, but I don't really know how to easily calculate that right now.

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1. ardel95 ◴[] No.45569349[source]
Kepler’s laws should still provide a pretty good estimate, at least until black holes get much closer. I did a quick back of the envelope calculation, and looks like they’ll be roughly 14k astronomical units, or 0.22 light years apart.