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Physicists Detect Gravitational Waves, Proving Einstein Right

nytimes.com

271–280 of 502 posts

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#271
post #84

I hope Kip Thorne gets a Nobel Prize for this, ideally while he's still alive.

Pedanticly, it'd have to be while he was alive since the Nobel Committee won't nominate anyone who's deceased. Rosalind Franklin would've surely received one for her work on DNA (among others who passed before their work was recognized).

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#272

Earlier quoted context omitted.

If gravitons have mass, then the universe is too strange to exist. Gravity is an interaction that defines the presence of matter (see dark matter). For the object that transmits that force between masses to itself have mass ... how can a black hole then project gravity? Imho whatever is carrying gravity between masses cannot itself have a mass.

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…

If the massive gravitron was leaving a black hole it would be slowed by the black hole's gravity.

(1) We should see this as some inconsistency in how gravity scales with the mass of a black hole. The larger ones would have proportionately greater 'drag' on leaving gravitrons, pulling more in.

(2) If they are massive, and therefore subject to slowing, shouldn't gravity waves leaving a black hole be subject to some sort of doppler effect? Should we be looking for red/blueshifts in these waves?

(3) If gravitrons have mass and are subject to gravity, what brings that gravity? What sub-gravitron particle regulates gravity going in/to/out of the gravitron? This would require a new set of particles be created by non-gravitron massive objects (ie black holes) alongside the gravitrons. Like I said, too strange to exist.

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#273

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".

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#274

Earlier quoted context omitted.

*Polynomially more objects. The volume of a constant-thickness spherical shell is O(r^2).

*Quadratically more objects.

less than quadratically because space is expanding in between

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#275

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 reverbates.

Note that the frequency of the signal is indeed in the audible range.

Anyway, I was a bit irritated of this same phrase, but because I tought radio astronomers had been listening to skies for quite some time now.

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#276
post #4

> 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…

Excellent catch. That's damn suspicious.

I may have suffered permanent eye damage from the rolling.

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#277

Are there any potential competing theories this detection could also support? I'm wondering how much room there is here for confirmation bias, but I suppose that's a pretty hard thing to measure without the benefit of hindsight.

Einstein–Cartan theory is the only viable classical alternative.

I am unfamiliar with modern alternatives to comment.

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#278
post #206

Earlier quoted context omitted.

Yeah,I got to the point mentioning the masses of the black holes before and after collision and said, "What, they didn't just lose three solar masses..." But, they did. Which was the order of predictions I'd read, years back, but egads . Considering how much larger that is than a supernova, I'd be concerned to have such an event happen in this galaxy...

The energy is dumped into gravitational waves rather than electromagnetic radiation & they don’t interact with matter much. I’m not sure you’d notice it happening in the same galaxy unless you were looking for it.

[deleted]

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#279

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…

If the massive gravitron was leaving a black hole it would be slowed by the black hole's gravity. (1) We should see this as some inconsistency in how gravity scales with the mass of a black hole. The larger ones would have proportionately greater 'drag' on leaving gravitrons, pulling more in. (2) If they are massive, and therefore subject to slowing, shouldn't gravity waves leaving a black hole be subject to some sor…

>(1) We should see this as some inconsistency in how gravity scales with the mass of a black hole. The larger ones would have proportionately greater 'drag' on leaving gravitrons.

Perhaps, no clue how a quantum mechanical gravity would interact with a black hole.

>(2) If they are massive, and therefore subject to slowing, shouldn't gravity waves leaving a black hole be subject to some sort of doppler effect? Should we be looking for red/blueshifts in these waves?

The Doppler effect happens even for light, which isn't massive at all (that we know of).

>(3) If gravitrons have mass and are subject to gravity, what brings that gravity? What sub-gravitron particle regulates gravity going in/to/out of the gravitron?

There's no reason they couldn't interact with themselves, in fact I guess that's probably the most likely case.

Re: Physicists Detect Gravitational Waves, Proving Einstein Right

#280
post #193

Earlier quoted context omitted.

I think the crucial detail you are missing from the article is this: "According to the equations physicists have settled on, gravitational waves would compress space in one direction and stretch it in another as they traveled outward." LIGO is two sets of 2 L-shaped antennas spread far apart on the globe, so that we can compare the compression of space in orthogonal directions and measure the very short delay between…

Here's my re-statement of this confusion, isn't everything we can experience embedded in time-space, including the LIGO experiment itself? So how is there any relative shift allowed to be detected when everything we know is fundamentally intrinsic to time-space? That is, I too would appreciate having this mis-conceptualizing, of mine, cleared away.

Another re-phrase: how can we detect that space has stretched out if all of our rulers also get stretched by exactly the same amount?

The answer is that we have a ruler that doesn't get stretched in this way: light. The speed of light is a constant dictated by the laws of physics; stretching out our flashlight to twice its normal size wouldn't make the light it emits go twice as fast. So if you just measure the time it takes for a light ray to go from one point to another, you can compute the distance that it must have traveled, and if that distance changes, then you know that the space in between must have been stretched.

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