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TFA says "they had heard and recorded the sound of two black holes colliding a billion light-years away" and "1.2 billion years ago". And from the paper: "The
by drx 11y ago
TFA says "they had heard and recorded the sound of two black holes colliding a billion light-years away" and "1.2 billion years ago".
And from the paper: "The source lies at a luminosity distance of 410+160-180 Mpcc corresponding to a redshift z=0.09+0.03-0.04.". (https://dcc.ligo.org/LIGO-P150914/public https://dcc.ligo.org/LIGO-P150914/public) Which corresponds to 1.337+0.522-0.587 billion ly (or between 750.2 million and 1.859 billion ly).
- mikeash 11y agoOops, missed that. Thanks! Looks like there are roughly three million galaxies within a billion light years. Seems like lots of space for black hole pairs to live in. I suppose over the coming years, these gravity wave observatories will nail down just how common they are.
- xenophonf 11y agoThat's around 1/60th the diameter of the observable universe!
- gradi3nt 11y agoSo that's wayyyyyyy outside our galaxy? Any idea how many galaxies fit into a 1 billion ly sphere around the milky way? I'm guessing a shit ton, which makes the detection of a bh merger seem more realistic to me. That's some serious range!
- jballanc 11y agoIt was mentioned during the press conference today that gravitational waves are not affected by interstellar/intergalactic dust the same way light is. In theory, once our detectors are good enough we should be able to use gravitational wave astronomy to peer all the way back to the big bang!
- nerfhammer 11y agoSo, we'll finally be able to hear what god said at the start of the universe?
- ddalex 11y agoThis is a beautiful premise for a mind bending book.
- mikeash 11y agoI'm sure He either said "let there be light" or "gee, that's funny...."
- mattmanser 11y agoI'd prefer either "what does this button do?" or "shit, don't press that!".
- tossaway1 11y agoIf these waves travel at the speed of light shouldn't the distance and time match up...?
- vanattab 11y agoNot if space time it'self is stretching while the light is in transit.
- deleted 11y ago[deleted]
- drx 11y agoThis would be true in a static universe, but, during the 1.2 billion years the waves have been traveling, the universe was experiencing accelerating expansion. For example, the edge of the observable universe is about 46.5 lightyears away, while the universe is thought to be 13.8 billion years. https://en.wikipedia.org/wiki/Observable_universe#Misconceptions_on_its_size https://en.wikipedia.org/wiki/Observable_universe#Misconcept...