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> It shows that, in some binary systems, the two black holes have misaligned axes of rotation, which would imply that they formed separately. But many other bin
by raducu 6y ago
> It shows that, in some binary systems, the two black holes have misaligned axes of rotation, which would imply that they formed separately. But many other binaries appear to have roughly aligned axes of rotation, which is what astrophysicists expect when the two black holes began their lives as a binary star system.
This is mindboggling -- you can tell two black holes from thousand of light years away had misaligned axes of rotation by measuring the effect they have on lasers bouncing some mirrors.
- AnimalMuppet 6y agos/thousands/billions/ That doesn't make it less mindboggling...
- raducu 6y agoBillions of light years? I thought the energy would be too faint, but given they found tens of mergers, it makes sense its actually billions, I don't suppose there are that many black hole mergers in our galaxy in this timeframe.
- AnimalMuppet 6y agoI seem to recall 3 billion light-years as the estimated distance of one of the early mergers detected. Can't cite a source, though...
- mabbo 6y agoIt really is billions of light years. Can you imagine the amount of energy released that we can detect these waves billions of light years away? It's mind blowing. In some of these mergers, two black holes combine but their total mass after merging is short by 1 to 5 solar masses. ALL of that mass was converted to energy to create the gravitational waves we picked up. Picture that- the entire sun converted to energy in the blink of an eye, times five.
- raducu 6y agoI read some article that the distortions at 10.000km from the merger would be ~1mm, so you could feel them, but not be harmed by them. In contrast, if all that energy was released as EM waves, you'd be cooked from far, far away. Such peaceful are these gravitational waves.
- jfengel 6y agoI'm not so sure that a 1mm distortion would be safe. It's happening at the level of space itself, so it would change the way parts of molecules will relate to each other. It passes fast, but potentially you could fall apart at the molecular level. I am not a physicist so I could be completely wrong about that. And I'm not sure if it matters since it's probably accompanied by photons and probably neutrinos in sufficient quantity to wipe you out at that distance. (Not from the merger itself, but from any matter in its halo.)
- amelius 6y agoI wonder how they focus the system on a particular area of the sky. Do they have an array of these systems?
- simonh 6y agoThere are three of them, two in the US and one in Italy. They can’t measure directionally individually, they just measure the gravitational waves at that location, but you can measure the different times a signal arrives at each and extrapolate from that.
- elihu 6y agoI think also the strength of signal detected has to do with the orientation of the detector with respect to the direction the gravity waves are travelling. So you can use the relative strength of multiple detectors pointing in different directions to infer the direction to the source.
- mabbo 6y agoThey actually can't! They're looking in all directions at once by having 2, and now three detectors on different parts of the planet. So when one thinks it's seen a GW, it has to correlate the observance with the others, and then they can say "Okay, so given the timing, which way did it come from?" and get a very rough direction. If it's a potential neutron star merger, they can then have everyone swing their telescopes in that direction to hopefully see it happen.