Interesting reading!
But I take issue with the title. The article says
"Laser Interferometer Gravitational Waves Observatory" (LIGO) in the USA, are able to detect these waves.
So not unseen, in as they've been seen :)
Curiously, its the fact that there was no visible light, that suggests it was this particular collision. Vs two black holes or two neutron stars. So I guess an indirect observation. Boy are astrophysicists clever!
Seeing is not the same as detecting. Can you call radioastronomy "seeing" when you can't see radio waves at all? Gravitational waves are even more "unseeable" in this respect.
The article made it perfectly clear what is happening
> The fusion of a black hole with a neutron star was first observed by gravitational wave observatories in August 2019. Yet optical observatories around the world were unable to locate an electromagnetic counterpart in the region from which the gravitational wave signal originated, suggesting that the black hole had completely devoured the neutron star without first destroying it. If confirmed, this could be the first observed black hole-neutron star merger detected in a dense stellar environment, as described by Dr. Arca Sedda.
They're not faster than C, but they could outrun a beam of light if there was some stuff hanging out in space and raising the index of refraction. In relativity the C limit is geometric, in the same way that "you can't make an apple bigger by rotating it around in your hands" is geometric.
The intergalactic medium (IGM) is very diffuse, but not pure vacuum. The difference in arrival time of light and gravitational waves from an event billions of light years distant could help measure the density of the IGM.
Incidentally, while it is very cold, the IGM is plasma, so obeys plasma fluid-dynamic laws, which is why the clouds seen at the ends of Active Galactic Nucleus jets, millions of light years across, can be visibly turbulent.
Here are my thoughts. Take them for what they are worth. I'm no professional. Someone who does this for a living will probably eye roll big time:
Gravity is the force exerted on mass due to a curvature of spacetime. It's faster to slow down your clock to get an extra second, move, and speed up your clock again than to just move. That's Relativity. Stochastic models scale out the subatomic probability models deriving temperature and pressure needed for containment. Combined with the photoelectric effect, viewing Planck's law in terms of particles, provides a model for acceleration.
Light transfers heat through electromagnetic radiation. No conductive surface, no convective medium. Your watch ticks, right? That's medium enough for nature. Every object already emits at the speed of light, the electromagnetic radiation. For the entire object to go the speed of light, everything around absorbs it, taking the easiest place to transfer heat.
The closest to instantaneous effects from what I know is Bell's Theorem. Grow a spinning coin at the speed of light through everything that exists, then stop it. Your side will be heads. You know every other side will be tails. You don't travel at all and instead build one object out of a lot of other separate things.
So to me, speed of light and gravity in terms of a theory of matter are a lot alike from very abstract physical models.
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[ 0.33 ms ] story [ 38.2 ms ] threadCuriously, its the fact that there was no visible light, that suggests it was this particular collision. Vs two black holes or two neutron stars. So I guess an indirect observation. Boy are astrophysicists clever!
We need a verb for gravitational perception!
Another example: you can observe a fire by smelling it.
The article made it perfectly clear what is happening
> The fusion of a black hole with a neutron star was first observed by gravitational wave observatories in August 2019. Yet optical observatories around the world were unable to locate an electromagnetic counterpart in the region from which the gravitational wave signal originated, suggesting that the black hole had completely devoured the neutron star without first destroying it. If confirmed, this could be the first observed black hole-neutron star merger detected in a dense stellar environment, as described by Dr. Arca Sedda.
The intergalactic medium (IGM) is very diffuse, but not pure vacuum. The difference in arrival time of light and gravitational waves from an event billions of light years distant could help measure the density of the IGM.
Incidentally, while it is very cold, the IGM is plasma, so obeys plasma fluid-dynamic laws, which is why the clouds seen at the ends of Active Galactic Nucleus jets, millions of light years across, can be visibly turbulent.
Gravity is the force exerted on mass due to a curvature of spacetime. It's faster to slow down your clock to get an extra second, move, and speed up your clock again than to just move. That's Relativity. Stochastic models scale out the subatomic probability models deriving temperature and pressure needed for containment. Combined with the photoelectric effect, viewing Planck's law in terms of particles, provides a model for acceleration.
Light transfers heat through electromagnetic radiation. No conductive surface, no convective medium. Your watch ticks, right? That's medium enough for nature. Every object already emits at the speed of light, the electromagnetic radiation. For the entire object to go the speed of light, everything around absorbs it, taking the easiest place to transfer heat.
The closest to instantaneous effects from what I know is Bell's Theorem. Grow a spinning coin at the speed of light through everything that exists, then stop it. Your side will be heads. You know every other side will be tails. You don't travel at all and instead build one object out of a lot of other separate things.
So to me, speed of light and gravity in terms of a theory of matter are a lot alike from very abstract physical models.