Author Topic: Question about gravitational waves detection  (Read 321 times)

Offline peter eldergill

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Question about gravitational waves detection
« on: February 02, 2021, 09:20:14 PM »
I understand about 50 events of gravitational waves have been detected.

My question is how many individual waves are detected per event? All articles or shows I've seen about it show only one wave. Do they see a series of waves or just one? It would seem that they should detect many waves coming in as the two massive objects spiral in

Cheers

Peter

Offline molesworth

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Re: Question about gravitational waves detection
« Reply #1 on: February 03, 2021, 06:23:33 PM »
I understand about 50 events of gravitational waves have been detected.

My question is how many individual waves are detected per event? All articles or shows I've seen about it show only one wave. Do they see a series of waves or just one? It would seem that they should detect many waves coming in as the two massive objects spiral in

Cheers

Peter
We've had a few talks at our local astronomy club from people involved in the project, and (as far as I understand it) each detected event is an oscillating signal, almost like a "chirp" if you converted it to an audio signal.  What's been detected is an oscillation which starts at a low-ish frequency and then ramps up to a higher one at the end.

Here's a YouTube video which kind of represents what it would sound like :

Days spent at sea are not deducted from one's allotted span - Phoenician proverb

Offline molesworth

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Re: Question about gravitational waves detection
« Reply #2 on: February 03, 2021, 06:29:28 PM »
Following on from the above, I can't recall if I've posted it before, but one of our speakers told us a great story about flying in to one of the LIGO sites, and the flight took them over the detector facility.

The woman sitting next to him said "You see that down there?  That's a secret government time travel research place.".

He asked her "So why are there two arms at right angles?".

She replied, "Well, obviously one's for going into the past and the other's for going to the future...".

So now you know, the future is perpendicular to the past  ;D
Days spent at sea are not deducted from one's allotted span - Phoenician proverb

Offline peter eldergill

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Re: Question about gravitational waves detection
« Reply #3 on: February 04, 2021, 12:14:41 PM »
Ok that's exactly what I was asking. I thought the chirp represented one wavelength. Now I see it's the increasing frequency of the entire wavetrain (is that the right word?).

That makes much more sense. Especially now I know the past is perpendicular to the future 🤔

Thanks

Peter.