# Expected sound of colliding black holes

1. Feb 1, 2006

### varsha

the sound of spinning black holes
in case your wondering where i got this from,well,here it is

Last edited: Feb 1, 2006
2. Feb 1, 2006

### |Orion's Thought|

Thats a very interesting link. I'm wondering why the ripples were turned into "popping" sounds instead of something else, such as ringing or pinging or something.

3. Feb 2, 2006

### varsha

i thought about it too. i guess they don't make that pinging noice because they will have to be moving very fast for that. well i don't know how to explain this(i'm very bad at it) but i think that ringing is sort of unnatural for things like blackholes.

The sounds of different vibrating objects are similar. and vibrations are caused by waves. any wave for that matter. as in this case it's gravitational waves. but if you listen to this closely, you'll hear that in the biggining the sound is not even close to the sound of normal vibrations. it's got that 'popping' sound as you say, but as they get closer(black holes) the sound is similar to the vibration of objects.

Here when i mentioned 'vibration of objects' i didn't mean that black holes vibrate

4. Feb 2, 2006

### |Orion's Thought|

Yes, I agree. Would it be safe to assume that the increased speed of the "popping" is due to the black holes getting closer together?

5. Feb 3, 2006

### varsha

yes i think it would be. as the bhs get closer, the speed of the 'popping' is increased. and i guess it's because of the gravity itself. at first the black holes are farther away from each other. and then they get closer by each other's gravity. as they get closer they get faster. so the sound created is also faster. though we can't hear them i think it's quite obvious.

6. Aug 9, 2009

### amezcua

Black----- that gives you a clue.No light gets out.Why would any sound get out? Star Wars SHOULD tell us that sound would not travel in(through,across,) space. But we are excited by clash of the giants events.Imagination takes us beneath frozen ammonia mountains beyond the reach of Sunlight.I used to enjoy imagining life on a pair of planets "stuck" together.What would gravity be like in that world.

7. Aug 9, 2009

### amezcua

Sorry I forgot the question mark.Science would never operate at all if just one molecule in the universe forgot to spin properly.So -------?-------Thats better. Ive just mended the Universe!

8. Aug 9, 2009

### amezcua

A clash of Black Holes might seem improbable.Here`s another improbable to match.I was reading a Maths book about an interesting problem when a sudden thunderstorm and torrential rain drove two people into shelter just outside the library window.I held the book against the glass and they could read my book problem-------How fast should you run in the rain? What are the odds? They both laughed.----Absolutely true.

9. Aug 10, 2009

### LithiumHelios

The gravitational waveform from coalescing binary black holes can typically be divided into three stages:

1. Inspiral
2. Merger
3. Ringdown

The inspiral part is where the two black holes are orbiting each other emitting gravitational waves from which orbital angular momentum is lost and the black holes can inspiral - this leads to a greater orbital frequency.

The merger is, as the name suggests, where the two black holes merge into a single perturbed black hole.

This final perturbed black hole will then proceed to 'ringdown' - it will emit gravitational radiation to shed itself of the deformities.

As the gravitational waves are emitted at twice the orbital frequency (well, predominantly) then the inspiral that leads to higher orbital frequencies produces that characteristic chirping sound as the frequency of the gravitational waves is increasing. The ringdown is often compared to the idea of striking a bell with a hammer and letting it ring. This produces the typical waveforms you can find on the LIGO pages and so on.

http://www.ligo.org/science/GW-Inspiral.php" [Broken]

Plenty to read up on here as well as the links it provides to member institutions. For example, check out some of the other gravitational wave sources.

Last edited by a moderator: May 4, 2017
10. Aug 11, 2009

### Blenton

Damn, didn't sound all that cool like I was expecting it to.