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LIGO detects most massive black hole merger to date

(www.caltech.edu)
360 points Eduard | 13 comments | 14 Jul 25 20:06 UTC | HN request time: 0.431s | source | bottom
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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. vjvjvjvjghv ◴[15 Jul 25 00:29 UTC] No.44566727[source]▶
I have read somewhere that an experiencing a supernova at sun distance would be the same as holding a hydrogen bomb to your eyeball. The energy released in these events is basically unimaginable.
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2. aaronharnly ◴[15 Jul 25 01:38 UTC] No.44567083[source]▶
Probably here:

https://what-if.xkcd.com/73/

And it’s even more astonishing — the supernova at 1 AU would be the same as a billion hydrogen bombs at your eyeball.

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3. scrollop ◴[15 Jul 25 06:10 UTC] No.44568313[source]▶
But, is it a small or large hydrogen bomb? And, what distance from your eyeball?
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4. vjvjvjvjghv ◴[15 Jul 25 08:40 UTC] No.44569190[source]▶
I’ll run some tests and let you know
5. mytailorisrich ◴[15 Jul 25 08:45 UTC] No.44569217[source]▶
Another way to look at it is that a hydrogen bomb is very small at planetary scale and so microscopically small at any astronomical scale.
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6. bravesoul2 ◴[15 Jul 25 10:28 UTC] No.44569730[source]▶
But you are safe at a parsec. Showing how also incredibly big space is. Space's bigness makes it hard to blow up a galaxy. Big bang excepted.
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7. mr_toad ◴[15 Jul 25 12:27 UTC] No.44570441{3}[source]▶
For certain values of safe. It’s close enough to strip the ozone layer, significantly increase the risk of cancer, alter the climate, and possibly cause extinctions.
8. thechao ◴[15 Jul 25 12:29 UTC] No.44570457{3}[source]▶
All the stars in the universe, burning as brightly as they are, are the tiniest fraction of additional energy compared to the 2.73°K background temperature of space. The Big Bang was very warm.
9. ordu ◴[15 Jul 25 12:34 UTC] No.44570492{3}[source]▶
It depends on the kind of supernova. Type Ia[1] is really insane. 10^44 J is a thing, that I think can blind you, even you've chosen a spot for your picnic to watch a Big Boom at distance of 1 parsec. A white dwarf made mostly of carbon burns all the carbon into oxygen in matter of seconds, and then it burns some of oxygen that was a result of burning carbon. It would like to continue brewing more and more heavy elements, but can't, because it becomes so hot, that gravity is no longer enough to keep the matter from flying away.

[1] https://en.wikipedia.org/wiki/Type_Ia_supernova

10. ithkuil ◴[15 Jul 25 13:44 UTC] No.44571109{3}[source]▶
Space is big and quadratic function grows fast
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11. aaronharnly ◴[15 Jul 25 18:43 UTC] No.44574490{3}[source]▶
I appreciate this point – it would take quite a few Tsar Bombas to approach the binding energy of a planet.
12. dredmorbius ◴[15 Jul 25 19:08 UTC] No.44574744[source]▶
At these scales, several orders of magnitude literally makes no difference.

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.

13. bravesoul2 ◴[16 Jul 25 01:48 UTC] No.44577905{4}[source]▶
Yes the same reasons your jet wash can't water your entire garden at once.