321–330 of 502 posts
Where can I find out more about how thermal effects in the LIGO optics are controlled for? Basically, I want to understand how it's possible to measure a distance change on the femtometer scale.
You probably want to read about their active isolation measures. Then you should find anything by Vladimir Braginsky you can get your hands on. This is a good start: http://www.amazon.com/Quantum-Measurement-Vladimir-B-Bragins...
I am not sure why but I am really hung up on the quote “Finally, astronomy grew ears. We never had ears before.” They are detecting gravitational waves not sound waves.
Earlier quoted context omitted.
Force carrying particles in general don't have mass. Except that some of them seem to do, which was rather puzzling for some time, but was solved using the Higgs mechanism. I can't think of an obvious reason the Higgs mechanism wouldn't work for gravitons, but I could be mistaken, it's not exactly the most intuitive area of physics. Also, keep in mind that the strong force transmits the force between colour charges w…
I'm going with the theory that black holes ARE gravitons themselves.
This made me wonder how far we are from being able to create and detect gravitons. The Wikipedia page on gravitons [0] addresses this question: Unambiguous detection of individual gravitons, though not prohibited by any fundamental law, is impossible with any physically reasonable detector. The reason is the extremely low cross section for the interaction of gravitons with matter. For example, a detector with the mas…
Surely we create gravitons whenever we move a mass just like we create photons whenever we move a body that interacts electromagnetically? Isn't the point that we're constantly exchanging gravitons with all matter as they mediate gravitational attraction.
Earlier quoted context omitted.
Not before they were solid state. Computers had their own buildings and relied on glass tubes for operation. Screens weren't on the radar. Operators were highly educated. But technology did bring us to a point where the vision became more focused, and led to what we have today. There are many possible paths to rebutting my statement, which to be clear is idle morning musing, but your objection doesn't hold water.
Is your speculation that the gravity wave detectors would be able to detect the changes in gravity caused by movements of people and things? Submarines already do this to detect other vessels AFAIK.
Beautiful.
I am not sure why but I am really hung up on the quote “Finally, astronomy grew ears. We never had ears before.” They are detecting gravitational waves not sound waves.
Any vibration is just a signal. We don't actually have a direct experience with a sound, hearing is our brains interpreting the nerve signals generated by tiny organelles jiggling in our ears. What is concrete then, is only the shape of the signal, but not the medium through which it propagates. This device just acts like a gigantic hearing device. Except it's not pressure waves, but the fabric of the universe which…
I am not sure why but I am really hung up on the quote “Finally, astronomy grew ears. We never had ears before.” They are detecting gravitational waves not sound waves.
The interference pattern is audible - a chirp that "rose to the note of middle C".
The amazing thing is they detected gravitational waves, not that they hooked up a speaker to the data.
I think a proper analogy would be if back when someone created the first function generator they connected it to a speaker. Then in an interview the main message they delivered was that you could now "hear electricity."
It just seems like they are focusing on an afterthought.
I also have no idea why I am so fixated on this. :-p
Could someone explain what possible applications this might produce?
Indirectly from the technology they had to develop to measure this, possibly something specially due to the precision they needed to measure this.
> And then the ringing stopped as the two holes coalesced into a single black hole, a trapdoor in space with the equivalent mass of 62 suns. All in a fifth of a second, Earth time. Am I reading this correctly, that shortly after the detector came online we just happened to observe the exact moment a billion years ago that two black holes collided? Was that extremely coincidental? Or do these events happen all the tim…
The predictions for the LIGO detection rate are very poor. They're based on a sample of just a handful of binary pulsars observed in our Galaxy, which would produce NS-NS mergers. The BH-BH merger rate is almost totally unconstrained, although it is generally thought to be less than the NS-NS merger rate. So the fact that a BH-BH merger was the first detection, and the fact that it was detected so soon after the sens…
Interested to know what they were shooting for when they spun this experiment up.