Einstein was a smart cookie.

Such a fortunate twist of fate that he was visiting the US when Hitler came to power in 1933.

speaking about gravity: http://okgo.net/2016/02/11/upside-down-inside-out-the-music-video/

nice discovery!!!

Does anyone else have trouble following any of this? None of the journalists are asking the questions I'd like answered, which isn't helping. I'd always assumed that black holes are pretty damned rare, that black holes orbiting each other were even rarer, and that to actually be around when it could be detected was damned unlikely.

Are they suddenly two a penny now, or have we been ridiculously lucky in a winning the lottery 3 times in a row sense? What were the odds of that happening?

Also, the next person to use the billiard ball on a rubber sheet talk should be shot. That doesn't explain anything.

The odds of that are exceedingly low. But two black holes colliding produce more energy lost to/power transmitted via gravitational waves than every star in the observable universe; and thus is visible from a billion light years away (from what i've read on this in the last day)

We know binary star systems aren't that rate. And we don't know how rare black holes are, because we have only ever detected (directly/inferred) super-massive black holes (again, according to what i've read in the last days)

But within a billion light years there are a LOT of galaxies, with lots of binary stars in each. When our previous most sensitive laser interferometer could only detect signals from 10 million light years, then sure, we might have had to be extremely luck to discover a signal at all. (Here i'm assuming that LIGO is 100 times more sensitive than the last experiment, which is a guess)

Either way, we have several probabilities we don't know, so you would expect to continue upgrading your experiments until getting hits becomes likely (and then you can start doing estimates of how rare blackholes actually are...)

I'm missing something in your post. Binary stars are common as muck, yes, but what has that to do with supermassive black holes? My knowledge of astrophysics is a little rusty, but I never recall anything suggesting a binary star system could develop into an unstable binary black hole system. Where these two not galactic centres from colliding galaxies?

"two blackholes colliding" does not imply supermassive blackholes. What I understand is that you don't need *supermassive* blackholes to get the big amount of energy that Orothaic is talking about. And blackholes can do form from sufficiently massive stars.
I don't know if you need that the two blackholes that will collide most come from a bynary system, but they certainly come either from stars or from other pairs of colliding blackholes. Actually, what I understand is that *supermassive* balckholes can only form after many not so massive blackholes smash together.

You want to talk about odds? The collision of the black holes was 1.3Billion years ago and it was detected 100 years after Einstein theory of general relativity. What are the odds of that?

what are the odds of maniac commenting exactly 35 minutes after I commented?

What principians said.

You don't have to be super massive to be a black hole.

The masses quoted are 20-40 solar masses (can't remember the exact figure)

And these are pretty common (in stars). The only reason i mentioned super-massive black holes (what thousands or millions of solar masses?) is that we have previously detected them. We have not previously detected any 'normal' blackholes - they were theory until this discovery.

@Maniac, pretty high if the occur once per year. But we've only got one confirmed example so maybe they only occur once per billion years, and then it is very lucky.

Of course there is a possibility that they were more common in the past, and once the majority of first-generation massive stars have collapsed to form black holes and collided with any nearby partner black holes, then the rates drops off substantially.

If that was the case, then you could argue that the more sensitive your sensor, the further back in time you can detect, the higher the probsbility of a collision being detected...

I presume it's also not a matter of sheer luck but also, in addition to what others have said, the developments in technology and knowledge that enable us to be more capable in our observations.

Lets look at the more interesting question. What happens if two black holes collide in our galaxy.

100,000 light years away, would make the collision appear 10,000 times more powerful - but energy dissipates over 3 dimensions of space (like light waves dissipating) so we'd detect a wave (10,000)^3 times more powerful - or 1,000 billion times more powerful. (10^13) which would ripple through the earth...

That goes from the quoted 1/10,000 th the width of a proton, to 100 million times the width of a proton (which i'd have to look up)

10^-15 m, so we should be fine ;)

There are many very interesting questions that we could ask ourselves, and it's not because of this discovery, many of the questions have been made before. The important thing to keep in mind is that if we are gonna proceed scientifically, the only correct way to answer this questions is to looking at data.

The importance of this discovery is that it implies that we are finally getting data to which to look at!

if black holes collide often, and create these gravity waves fairly frequently, (frequent in a cosmic sense, occasionally in the scale of our civilization) then it could be one of the "great filters" theorized in the Fermi-paradox, preventing space travelling civilizations from developing.

Hmm not sure I agree with that conclusion. The point of a 'great filter' is that it's extremely hard to get past but once you're past, you're past, right?

How would one survive nearby (in a cosmic sense) black hole collisions? Is that a hurdle one can ever pass?

I also agree that I've found the reporting quite unscientific so far.

Depends on what you call nearby. Aside from creating gravitational waves I'm not sure what a collision between two black holes actually does.

Allows Matthew Mcaughnohey to get home to his daughter man.

What is a "daughter man"?

Sometimes I can't keep up with transgender terminology.

@Octavious: My point was merely that I think it's unlikely that a lethal black hole collision situation, whatever that is, suddenly becomes non-lethal thanks to advancements of a species and therefore being a hurdle to pass.

My point is that I don't know how lethal a black hole collision would be. Black holes are so called because not a lot comes out of them. If two collide it could just be that double the amount of destructive energy doesn't come out of them. Maybe a bit more guff gets squirted out the poles. In terms of galactic doom it may well be something of a non event.

Worst case scenario, I'd imagine, is that the BHs get dislodged from their happy place and instead get thrown out on a new galactic trajectory cutting a mighty slice of nothing surrounded by chaos through the galaxy. Best case is nothing really changes aside from a gravitational ripple. Either way, if it happened in the centre of our galaxy we wouldn't know for over 20,000 years.

The exact solar masses I heard on NPR this morning were 29 and 36, with error bars of "tens of percent," according to one of the scientists who worked on the project. He also claimed these sorts of events happened frequently. Checking online, I see 'theorists' predict five more black hole merges this year and forty binary star merges, all of which should be detectable by LIGO. So much for winning the lottery, I guess. FWIW, binary black holes can emerge from binary star systems or from galactic merges (and the latter would produce some REALLY BIG black holes).

Source for the frequency claim:
http://www.skyandtelescope.com/astronomy-news/gravitational-wave-detection-heralds-new-era-of-science-0211201644/

29 + 36 = 65 solar masses
But to detect this, tens of solar masses of energy were released (you can think of yhis as the binding energy, how much energy it would take to seperate these two black holes) it wa this energy causing a ripple in space-time which was detected.

It proves that Einstien was right, and orbiting bodies can give off energy, allowing their orbit to decay. Thus allowing two orbiting black holes to collapse into each other.

How the energy could damage us is another question. I think we have computer chips small enough to be affected briefly (by this space-time quake) but i suspect all our biology would be fine (based on my estimates above of a black hole inside our galaxy but not nearby).

That said, i don't understand how / if this energy can be absorbed. It propogates through space; i imagine another ossilating mass could asborb it, much like a electronagnetic wave ( think radio ) but we don't have anything like that. So, no, i don't think this resolves the fermi-paradox.

Agreed with ora.

Octavious: I wasn't trying to say that it's dangerous, the point was rather that I think he's probably wrong even *if* he was right about the first bit.

actually the final black hole is 62 solar masses, releasing the energy of 3 suns in a fraction of a second. That's what makes it "shine brighter than all the stars in the universe."

Imagine the energy that the sun puts out. now imagine all of the the energy it will ever put in in it's 10 billion year life, times 3, released in a fraction of a second. It'd still be astronomically higher than this because the entire sun would have to dissipate in order to release ALL of its energy.

This, i thought i saw an estimate closer to 10 solar masses. But regardless, the sun is powered by fusing hydrogen into helium and eventually into carbon and iron.

But this still leaves the while mass of iron nucleii which is a fairly large percentage of the totaly mass-energy. (I'd guess 80-90%)

This is so much more power released that anything we've ever seen before - likrly only to be outdone by the collision of two gaxalies, when their super-massive blackholes join. (Dear Andromeda, can't wait to see you, yours, the Milky Way)

It is hard to get your head around an energy release of that magnitude having such a small observable impact.

Well, gravity is a very weak force. Consider that the black hole merger had been happening for a very long time before the observable bit (hundreds of millions of years, I believe), but the waves produced by that activity would have been far too low-frequency for us to detect. Really, anything that can shake the fabric of spacetime itself a billion light-years away has got to be unimaginably powerful.

Not really. Me flapping my arms about can shake the fabric of spacetime itself a billion miles away. It's just a question of by how much.

Anything that can *detectably* shake the fabric of space-time, etc. Excuse my dropped word.

@Ovtavious, 1) what volume of space is that energy dispersed over?
2) how much energy do you think it takes to warp space?

@ ora

1 lots
2 virtually none

@ Leth

If there is one lesson to learn from the past few days it's that what is or isn't detectable can change quite dramatically. By the time my hand flapping travels a billion light years who knows what will be possible.

Most likely all humanity will be dead, in which case the Sun going nova would be undetectable, but again, who knows?

Octavious, my meaning was pretty clear, and I don't see any point in sniping at me merely because "detectably" wasn't explicitly qualified with "by current instrumentation". Obviously I am not talking about the detection capabilities of a civilization a billion light-years away, in a billion years.

What on earth makes you think I'm sniping at you?

Apparently Gregg Harry played diplomacy at MIT

The part where you repeatedly frame your remarks as nitpicking my statements with no value-add is a hint.

You yourself initiated this line of conversation by musing on how small the observable impact of the black hole merger was given its immense energy release. If by 'observable' you were talking about 'hypothetically observable by a civilization a billion light-years away in a billion years,' then the observable impact of the black hole merger would not have been small to begin with. But when I entered the conversation, you shifted the basis of your comments and picked at me for not accounting for sufficiently small-scale waves, even though your initial comment had nothing to do with those. You understand why this might be frustrating to me.

I have absolutely no idea why it'd be frustrating to you. None of us are experts, just enthusiastic amateurs musing over possibilities. A uni tutorial without the professor

Well, if none of that explanation registered with you, then I suppose that explains a lot, and I'll account for it in future conversation.

I didn't need to "science" to prove gravity waves. All I need to know was that everytime I dropped my shorts, ONE of your Momma's was drawn to my source.

'Nuff said.

Peace out.

Is it weird if I say I missed you again, krellin?

The observable universe is dependant on your position in time and space. Thus we are observing waves that are in our now , another part of the universes far past, and another parts distant future..

I love the fact that the sheer size of the thing is what stuffs up most people.

I do think Sci-fi has had a negative contribution for making the universe smaller and more manageable.

Love the waves lets surf them to creations beginning/end.

By Pretoria I assume you mean Tshwane.

Wrong thread, Putin.

No, this is dadaism. You're uncultured, you don't understand.

I'm pretty sure we established that I've been forcibly cultured :-)

thought I'd use this thread as a pretext to share a blog I like:

http://www.math.columbia.edu/~woit/wordpress/?p=8306