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LIGO detects most massive black hole merger to date

(www.caltech.edu)
360 points Eduard | 2 comments | 14 Jul 25 20:06 UTC | HN request time: 0.435s | source
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WrongOnInternet ◴[14 Jul 25 21:27 UTC] No.44565549[source]▶
> 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.

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aaronharnly ◴[15 Jul 25 00:27 UTC] No.44566715[source]▶
Let’s see — the Tsar Bomba nuclear weapon released the equivalent of converting about 2.3 kg of matter into energy (1).

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.

(1) https://faculty.etsu.edu/gardnerr/einstein/e_mc2.htm

(2) https://solar-center.stanford.edu/FAQ/Qshrink.html

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1. lxe ◴[15 Jul 25 03:23 UTC] No.44567584[source]▶
Is it physically limiting for a theoretical civilization to harness and use such energy?
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2. Thiez ◴[15 Jul 25 11:34 UTC] No.44570080[source]▶
The energy is emitted as gravitational waves which is probably tricky to convert into usable energy and you probably can't attend more than one in your life unless you have faster-than-light travel. You're much better off visiting a supernova.

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.