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Astrophysicists unveil glut of gravitational-wave detections

nature.com

51–60 of 108 posts

Re: Astrophysicists unveil glut of gravitational-wave detections

#51
post #37

Just curious, if we have gravitational waves, what are the wave lengths?

That depends the period of the body’s movement. The wave is generated by the body’s movement.

OK I probably got some wild thoughts. I was thinking, since light has different wave lengths and human can't see many types of light because of that, maybe dark matter is similar?

Just some uneducated thoughts lol.

Re: Astrophysicists unveil glut of gravitational-wave detections

#52
Do gravitational wave interferometers create a single pixel of data, or do they create an "image" of gravitational distortion in a 2D region? The first few Google/Wiki hits talk about the physics of interferometry, but not the actual resulting output from real hardware. I'm assuming there is no image, otherwise there would be some associated with the articles, rather than artistic renditions?

Re: Astrophysicists unveil glut of gravitational-wave detections

#53
post #20

The article mentions the new KAGRA detector in Japan joining the group. Does anyone know: how does the accuracy improve as more detectors come online? Will we see a day where we have 20, 50, 100 detectors around the globe and events are near-certain because so many detectors see them? Or is the diminishing returns, and 4 detectors is already too many?

The current ones are Louisiana, Washington state, and Italy.

So having another as far away as Japan should improve triangulation substantially.

Re: Astrophysicists unveil glut of gravitational-wave detections

#54
post #12

LIGO blows my mind whenever I hear news about it. The sensitivity alone is insane -- it can detect a change in distance between its mirrors 1/10000th the width of a proton. This is the equivalent of measuring the distance to the nearest star (4.2 light years) to an accuracy of 1 human hair . Those are bonkers numbers. How the hell did we even come up with this thing?

*the second nearest star

:)

Re: Astrophysicists unveil glut of gravitational-wave detections

#55

Do gravitational wave interferometers create a single pixel of data, or do they create an "image" of gravitational distortion in a 2D region? The first few Google/Wiki hits talk about the physics of interferometry, but not the actual resulting output from real hardware. I'm assuming there is no image, otherwise there would be some associated with the articles, rather than artistic renditions?

They measure the total distortion over the baseline, so in that sense it's a single pixel. But I think measurements from several interferometers can be combined to give some very limited spatial resolution.

Re: Astrophysicists unveil glut of gravitational-wave detections

#56
post #37

Earlier quoted context omitted.

That depends the period of the body’s movement. The wave is generated by the body’s movement.

OK I probably got some wild thoughts. I was thinking, since light has different wave lengths and human can't see many types of light because of that, maybe dark matter is similar? Just some uneducated thoughts lol.

But it’s a very good question. It leads to what’s the nature of gravitational wave. The frequency is certainly a key characteristic. It can lead to how LIGO works.

Re: Astrophysicists unveil glut of gravitational-wave detections

#57
post #12

LIGO blows my mind whenever I hear news about it. The sensitivity alone is insane -- it can detect a change in distance between its mirrors 1/10000th the width of a proton. This is the equivalent of measuring the distance to the nearest star (4.2 light years) to an accuracy of 1 human hair . Those are bonkers numbers. How the hell did we even come up with this thing?

Interferometry has a long history in experimental physics. The Michelson–Morley experimental design scaled up to large distances and using modern technology, like lasers and computers, gets you LIGO.

And resonant cavities, the best mirrors ever made, and a huge amount of cleverness and work over 40+ years.

Re: Astrophysicists unveil glut of gravitational-wave detections

#58

Do gravitational wave interferometers create a single pixel of data, or do they create an "image" of gravitational distortion in a 2D region? The first few Google/Wiki hits talk about the physics of interferometry, but not the actual resulting output from real hardware. I'm assuming there is no image, otherwise there would be some associated with the articles, rather than artistic renditions?

You can think of each individual detector producing a single-channel audio signal. By combining the signals from multiple detectors it's possible to determine where the signal is coming from. But the output is neither a picture nor a single pixel: it's a brief blip of a few seconds of audio-frequency time series.

A decent analogy is to think of each LIGO detector not as a camera but a microphone.

Re: Astrophysicists unveil glut of gravitational-wave detections

#59
post #18

LIGO is a huge milestone. Turning it on is like the moment Galileo pointed his telescope to the moon. This is a new class of instruments observing the universe in a medium that was never utilized before. Using gravitational waves can observe things that cannot be seen before, like stars behind the dust clouds. It opens a new window to the world. We might finally be able to “see” dark matter. May be able to see the gr…

I hope to live long enough to see the evolution of interferometers that will be to LIGO as HST was to Galileo's telescope.

This is what you're waiting for: https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Ant...

Re: Astrophysicists unveil glut of gravitational-wave detections

#60
post #7
post #3

the Gravitational Observatories are so impressive to me - I can remember reading about them being theoretical well before LIGO ever started construction, and the fact that theyre here and working just like we expected is so amazing. I can't wait until we have LISA in space! But its so strange when we shut it off to do upgrades and stuff - like I totally understand why we have to do it, but its like we finally turned…

LIGO collaboration member here: we focus on maximizing the cumulative number of detections over time, and it turns out that by turning the detector off for a year to upgrade it, we can increase the sensitivity so much that a year after that we will have more total detections than if we had left it running continuous for two years. So you also have to think about all the distant/faint signals we would never be able to…

Also the experimentalists get very antsy when they/(we) can't touch the instrument. :-)
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