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Community => Science and Technology => Topic started by: dpareja on October 16, 2017, 03:18:01 pm

Title: Astronomers see source of gravitional waves for the first time
Post by: dpareja on October 16, 2017, 03:18:01 pm
http://www.cbc.ca/news/technology/astronomers-see-gravitational-wave-neutron-star-1.4350339

Over 100 years ago, Albert Einstein predicted in his general theory of relativity the existence of gravitational waves.

Two years ago, these were detected for the first time, and have been detected on a few occasions since, but always from the collision of black holes, leaving nothing visible to be detected.

This time, however, astronomers were able to detect not only the waves but also see their source, as they resulted from the collision of two neutron stars.

SCIENCE!
Title: Re: Astronomers see source of gravitional waves for the first time
Post by: Tolpuddle Martyr on October 16, 2017, 04:52:30 pm
It always messes with my head a bit that spacetime can ripple like a wave and form "wells". Like it's stuff.

Wibbly wobbly, timey wimey...
Title: Re: Astronomers see source of gravitional waves for the first time
Post by: dpareja on October 16, 2017, 05:29:08 pm
There's a reason Einstein won his Nobel Prize for his explanation of the photoelectric effect and not for his theories of relativity.
Title: Re: Astronomers see source of gravitional waves for the first time
Post by: Askold on October 23, 2017, 01:10:38 am
Gravitational waves make more sense to me than gravitons.

I can understand that mass has an effect on the world and leaves a "dent" so to speak. But gravitons mean that instead it's just that every single atom sends teeny tiny particles to each other and these particles attract everything thus creating gravity.

...How is that supposed to work? Won't the gravitons run out at some point? Doesn't it mean that there is a bit of delay before gravity starts to have an effect? (Ok, gravity waves cause the same issue with me but somehow offend me less.) Won't the gravitons impact with each other and redirect meaning that really big objects are just a mess of bouncing gravitons and atoms? AAAAAAAH!

The only thing that comforts me is that despite me being certain that they had already discovered gravitons Wikipedia still says that it is only theoretical and (unlike gravitational waves) has not been proven to exist. I still retain hope that this particular monstrosity does not exist and the world is a logical place where weight makes a 4D reality bend with no need for tiny gravitons.
Title: Re: Astronomers see source of gravitional waves for the first time
Post by: Sigmaleph on October 23, 2017, 05:48:27 pm
Suddenly I am very curious if you find the existence of photons equally offensive.

Because, like, a lot of the appeal of gravitons as an idea is that all the other fundamental forces have a particle associated with them; photons for electromagnetism, W and Z bosons for the weak interaction, gluons for the strong interaction.

Also, to take a stab at answering your questions: no, you can't run out of exchange particles. There isn't a finite supply, new ones are created and destroyed all the time.
Yes, there's a lightspeed delay on gravity. It would be weird if there wasn't; if the effects of gravity were immediate you could theoretically use that for FTL signalling and break causality.

(guessing here) I think gravitons can interact with each other, but you shouldn't think of it as tiny balls crashing against each other and bouncing off in whatever direction. Fundamental particles are screwy and do not behave like macroscopic objects. Also, their only interaction would be gravitational anyway, and gravitational interaction is super weak at that scale, so they wouldn't interact a lot.
Title: Re: Astronomers see source of gravitional waves for the first time
Post by: dpareja on October 23, 2017, 06:10:48 pm
Gravitational interaction is super weak at any scale... it's just that charge doesn't scale with size the way mass does.

I know there's one notion in string theory that says that gravity is every bit as strong as the other three forces, just that it mostly acts in one of those other seven dimensions.
Title: Re: Astronomers see source of gravitional waves for the first time
Post by: Askold on October 24, 2017, 09:35:00 am
I will confess that I have very little knowledge on physics and it may be that my stupidity is what causes me to rage against the laws of the universe.

Really, I'm one step away from a guy who insist that the entire world sitting on the back of a turtle "just makes more sense."
Title: Re: Astronomers see source of gravitional waves for the first time
Post by: dpareja on October 24, 2017, 01:45:03 pm
Thankfully, science doesn't work on the basis of "what makes more sense."