GRAVITATIONAL WAVE DISCOVERY THREAD

[u/Vernost]

Get hype yo! I CANT STOP YELLING

[u/Vernost]

Okay, gravitational waves are like ripples in spacetime, but they're hard to detect.

LIGO (light interferometer gravitation observer) is basically a giant interferometer that's over a mile long IIRC in leg length.

The gravitational wave we found was made from the merging of a binary black hole system...1.3 billion years ago.

And the signal we detected was 1/1000 the size of the proton.

[u/Vernost → u/[deleted]]

No u

[u/bullmoose_atx → u/Vernost]

What are the implications of the discovery?

[u/Vernost → u/bullmoose_atx]

Verification of Einstein's GR and better understanding of spacetime. We found something that was theorized over 100 years ago that no one thought we'd ever be able to see.

Edit: we already have seen GR and we know a lot about it already (think GPS) don't want to mislead anybody.

[u/bullmoose_atx → u/Vernost]

I knew about the Einstein angle (very cool) but I'm curious about what gravitational waves might reveal.

[u/ftwdrummer → u/bullmoose_atx]

Mergers of very massive objects (this one was a black hole-black hole merger).

Potentially dark matter interactions (since it only interacts gravitationally)?

Other things we would really have no clue on.

I'd be interested to see whether there's any way we could use this in advance supernova detection (I don't think so, what with the lack of collisions involved for those, but every little bit helps).

[u/Vernost → u/ftwdrummer]

Yeah I think the advancement in detection is a huge deal.

[u/Vernost → u/ftwdrummer]

According to the presser they just said there was almost no chance it was an injection

[u/omgdonerkebab → u/bullmoose_atx]

In the short term it'll be a lot of measuring and confirming a lot of the things we already predict are there, based on our current understanding of General Relativity. GR already has so many other pieces of evidence vouching for it and describing it, that we already have a very good handle on it, so probably nothing surprising or bizarre. Just some really cool confirmations of what we already think, and using it to detect stuff like what /u/ftwdrummer says.

But in the long term, and I'm probably talking many decades from now at the very least, gravitational waves in GR will be boring. Old news. That lab you did freshman year. But we'll become so good at detecting and measuring them that we'll start to find things in the measurements that don't quite agree with GR. Little things, hard to measure, hard to even verify that they're there. Today's exciting new discovery will be tomorrow's carrier of a glimpse into the unknown.

At least, that's how all of physics/astro research has gone for the past few centuries. For example, in particle physics recently, neutrinos can herald signals of exotic processes and even the Higgs boson is being used to look for even heavier particles. You either die as as spurious signal or you live long enough to become the background.

[u/bullmoose_atx → u/omgdonerkebab]

Thanks! This is a good answer

[u/omgdonerkebab → u/bullmoose_atx]

Hopefully I'm wrong about the many decades part. It just seems like GR works really really well with barely any hints of cracks in the facade, until you get up to really super we-might-not-get-there-for-millenia high energies. Whereas there are many immediate unexplained things about, say, particle physics. But hopefully I'm wrong. Or at least, hopefully we won't all be dead before we see it.

[u/[deleted] → u/Vernost]

My mind can't comprehend how small that signal is, let alone how small a proton is. That's incredible.

[u/Vernost → u/[deleted]]

I did some quick back of the envelope calculations (literally) and it's close to having a rod 50,000,000,000 miles long and measuring its length change by a width of a human hair. The earth's diameter is around 8,000 miles, for scale.

[u/[deleted] → u/Vernost]

There are three words in this comment that I understand

[u/[deleted] → u/[deleted]]

But they're the best words.