After analyzing the data from LIGO's brief engineering run the scientists there just announced they have found a second Black Hole merger. A Black Hole of 14 solar masses merged with one of 8 solar masses and produced a Black Hole of 21 solar masses and gravitational waves with 1 solar mass of energy. It happened 1.4 billion light years away, about the same distance as the first merger that was announced a few months ago, but the signal was weaker because the Black Holes involved were smaller (14 and 8 vs 36 and 29) and also because the orbit of the Black Holes was more edge on relative to the Earth. Edge on means the signal is weaker but it also means it's easier to determine the spin, so unlike the first detection this time we can say with certainty that at least one of the Black Holes was spinning. And although weaker the signal lasted longer, almost a full second versus a fifth of a second the first time because being smaller the holes generated waves with higher frequencies that LIGO is more sensitive to.
And they're looking at at least one other suspected merger but they're only 85% certain it's real and that's not good enough to claim discovery, but there may be others so there may be a third announcement before long. Not bad for observing for only 18 days. The instrument was running at only one third power but that was still good enough to determine that 2 mirrors 4 kilometers apart had changed their distance by less than a billionth of a nanometer. I can't wait for September when the 2 LIGOs get back online and are joined by a third detector, VIRGO in Italy. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103 John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
