LIGO gravitational wave announcement

[surreptitious57]

Dark energy and dark matter are placeholders for phenomena which are not fully understood. Now while they might be
invisible they are not undetectable. They may be impervious to light but are not to gravity because anything with mass
will have gravitational effect. Dark matter is attractive and dark energy is repulsive. But dark energy accounts for most
of the missing ninety six per cent of the universe which also includes dark matter. And which is why its effect is greater

 

[JeanTate]

Reaction to the recent news:

Finally some scepticism.

You use words in a very funny way, Maartenn100 (at least, funny to me).

I had not - to my knowledge - encountered "scepticism" as a synonym for "denial" before; has any other reader (other than by Maartenn100)?

 

[Craig B]

It increased as the black holes drew closer (and orbited faster), but... 2000 km at it's peak, according to this factsheet, if I'm reading that correctly.

In one second the merging black holes released energy which was equivalent to three solar masses, and emitted this energy at a wavelength of 2000km. That's quite startling. One gets used to reading about bigger and bigger cosmic bangs like gamma ray bursts and so forth, but this one is stupendous even by these standards.

I have two questions, if anyone has the information.

Was most or all of the energy released by this event emitted in the form of gravity waves, or was there a pulse of electro-magnetic radiation associated with the gravity disturbance? If so, what part of the spectrum did it peak in, and how much of the three solar masses of energy would it have accounted for?

In its entire life as a normal star, (ten billion years, not one second!) how much energy will the Sun emit, expressed as a fraction of its mass?

 

[JeanTate]

Why do stars in a binary system not die at the same time? Does one have larger mass than the other or is one older than
the other? Are binary black holes rare because the stars have insufficient mass to become black holes? Or is that one dies
first and becomes a black hole and sucks the other one in when it becomes a black hole that then leaves only just the one

Answers to all these questions can be found in the paper (preprint actually) I cited in my earlier post, Astrophysical Implications of the Binary Black-Hole Merger GW150914, although answers to your first question ("Why do stars in a binary system not die at the same time?") are in the papers cited, rather than the paper itself.

May I ask, did you read arXiv:1602.03846?

Assuming that you did, in fact, read it, would you care to have a go at answering your own questions?

 

[JeanTate]

<snip>

Was most or all of the energy released by this event emitted in the form of gravity waves, or was there a pulse of electro-magnetic radiation associated with the gravity disturbance? If so, what part of the spectrum did it peak in, and how much of the three solar masses of energy would it have accounted for?

<snip>

As I read it, the results (~3 sols of mass turned into energy, in a fraction of a second) refer to energy carried by gravitational waves (not gravity waves), and are based on 'numerical relativity' models.

How much EMR is expected to be released in such a BBH inspiral? This was asked at the DC news conference yesterday (and is in the livestream); the answer was, IIRC (my paraphrase), "unknown, but likely very little, cf the GWR, even if there was an accretion disk".

Elsewhere, I asked about what effect intense GWR is expected to have on the immediate environs of an inspiral BBH, but no answer (so far).

Swift looked for a gamma-ray and x-ray signal from GW150914, but found none ("Swift follow-up of the Gravitational Wave source GW150914" - link is to astro-ph preprint)

 

[Craig B]

As I read it, the results (~3 sols of mass turned into energy, in a fraction of a second) refer to energy carried by gravitational waves (not gravity waves), and are based on 'numerical relativity' models.

How much EMR is expected to be released in such a BBH inspiral? This was asked at the DC news conference yesterday (and is in the livestream); the answer was, IIRC (my paraphrase), "unknown, but likely very little, cf the GWR, even if there was an accretion disk".

Elsewhere, I asked about what effect intense GWR is expected to have on the immediate environs of an inspiral BBH, but no answer (so far).

Swift looked for a gamma-ray and x-ray signal from GW150914, but found none ("Swift follow-up of the Gravitational Wave source GW150914" - link is to astro-ph preprint)

Thank you for that informative response.

The "gravity waves" in my post was a simple slip. I know that these are something different.

 

[thedopefishlives]

As I read it, the results (~3 sols of mass turned into energy, in a fraction of a second) refer to energy carried by gravitational waves (not gravity waves), and are based on 'numerical relativity' models.

How much EMR is expected to be released in such a BBH inspiral? This was asked at the DC news conference yesterday (and is in the livestream); the answer was, IIRC (my paraphrase), "unknown, but likely very little, cf the GWR, even if there was an accretion disk".

Elsewhere, I asked about what effect intense GWR is expected to have on the immediate environs of an inspiral BBH, but no answer (so far).

Swift looked for a gamma-ray and x-ray signal from GW150914, but found none ("Swift follow-up of the Gravitational Wave source GW150914" - link is to astro-ph preprint)

Part of the problem with trying to detect an EM spectrum signal, as I understand it, is that with only two operational observatories, LIGO was unable to pinpoint the source of the gravitational wave event to a reasonable degree of accuracy; IIRC, it was something like a 140-degree sector of sky in the Southern Celestial Hemisphere. That's a lot of space to search for an EM signal, and not a lot of time to capture it in - and that's assuming that the EM burst wouldn't be directional, like a relativistic jet, which would also have the constraint of needing to be aimed in our general direction to be detectable.

 

[Craig B]

... Elsewhere[/URL], I asked about what effect intense GWR is expected to have on the immediate environs of an inspiral BBH, but no answer (so far).

Yes, I was wondering what would have happened if we had been much closer to the event, so that let's say the arms of the LIGO momentarily changed length by a hundred metres. Would that have caused utter disruption of all material structures, including the planet, or would it just have rippled past leaving things as unaffected as is a cork floating on a pond agitated by a breeze?

 

[JeanTate]

The Confrontation between General Relativity and Experiment, by Clifford Will, is, I suggest, essential reading for all those who wish to 'reject GR' (link is to his 2014 version; there are earlier ones too).

It's also of potential interest for those curious to know just how extensively GR has been tested, in labs here on Earth, in experiments in space, and by (astronomical) observations. It's not an easy read, even if you have a degree in physics, but I think well worth the effort of persevering. One great thing: Will has an enormous number of references, so you can, relatively easily, go read the primary sources.

 

[JeanTate]

Part of the problem with trying to detect an EM spectrum signal, as I understand it, is that with only two operational observatories, LIGO was unable to pinpoint the source of the gravitational wave event to a reasonable degree of accuracy; IIRC, it was something like a 140-degree sector of sky in the Southern Celestial Hemisphere. That's a lot of space to search for an EM signal, and not a lot of time to capture it in - and that's assuming that the EM burst wouldn't be directional, like a relativistic jet, which would also have the constraint of needing to be aimed in our general direction to be detectable.

(my bold)

600 square degrees. And yes, if Advanced Virgo had been 'up' at the time, the likely direction could have been nailed down to ~10 square degrees (90% confidence). With a fourth observatory, perhaps even ~1 square degree (depends on where they're all located, and where, in the sky, the signal comes from).

There's also the issue of 'local' absorption ... if the source were 'behind' a GMC (giant molecular cloud), or just a lot of dust, either in the host galaxy or our own (or the LMC!), it's likely only hard x-rays and gammas (and, maybe, radio) would have been observable.

On top of which, as I understand it, there is nothing to suggest what part(s) of the electromagnetic spectrum any associated EM signal would be strong in ... and if it were EUV, for example, we'd never see it.

 

[tusenfem]

Maarten, can you come up with anything at all that would explain receiving identical signals at two different locations 3000 km apart, separated by 7 milliseconds?

not only that but also the very good correspondence with a model signal

 

[Daald]

I had not - to my knowledge - encountered "scepticism" as a synonym for "denial" before; has any other reader (other than by Maartenn100)?

You have to check out the conspiracy theory section A lot of conspiracy theorists do this to look like they know what they are talking about to the layman. When they try their BS on people educated on the topic they just end up looking foolish.

 

[fuelair]

And, let's be fair, if someone claiming telekinetic powers were able to produce, on demand, an effect - even of this magnitude - at two separate locations, with this good agreement between the two traces and this good agreement between what he expected to produce and what was actually produced, then that would be a pretty convincing proof of telekinesis.

Maartenn1000, look at the actual traces. They're easy to find, just follow the links upthread. There's clear and convincing data published, and it's far more comprehensive than the random single movement you seem to think it is.

Dave

Maartenn is only 100 not 1000!!!!

 

[Denver]

I wonder how long until someone begins selling special material, cleansing drinks, or gadgets to protect one’s health from the harmful effects of gravity waves?

 

[thedopefishlives]

I wonder how long until someone begins selling special material, cleansing drinks, or gadgets to protect one’s health from the harmful effects of gravity waves?

As we've clearly seen, these waves have the power to shift anything in their path by nearly 1/1000 the width of a proton. Therefore, they can have significant negative effects on your mental and physical health. This is why you need to carry my special depleted uranium wallet; it will redirect the nasty movement of gravitational waves to the money contained therein, causing said money to land in my bank account. But it'll keep you safe!

 

[mbarrett]

From some locations in space of merging black holes, the angle of arrival of the gravitational wave at the two arms of a detector will be equal. At this angle no differential length change will occur, thus cancellation, and no output signal seen. In these directions in space (which encompass a whole plane) the observatory has zero sensitivity i.e. is blind. I see no discussion of this limiting effect.

 

[Dave Rogers]

Maartenn is only 100 not 1000!!!!

Whoops. Still, we're talking about cosmology, so it's OK to be out by only one order of magnitude.

Dave

 

[Darat]

I wonder how long until someone begins selling special material, cleansing drinks, or gadgets to protect one’s health from the harmful effects of gravity waves?

Or claim they are GW intolerant!

 

[NoahFence]

This is damn fascinating. A whole new way to look at the universe! Visible light, Radio Waves, IR... and now Gravity Waves. Amazing. We need to learn how build an observatory that can be pointed like a telescope.

 

[NoahFence]

Reaction to the recent news:

What's this guy's area of expertise?