Keith F. Lynch wrote:
As a sanity check, I divided the reported peak power output of the
event, 3.6E49 watts, i.e. 200 solar masses per second annihilated,
by the area of a sphere 1.3 billion light years in radius. I get
about 20 milliwatts per square meter. What accounts for the factor
of two discrepancy? Probably polarization. LIGO, if I understand
correctly, is sensitive to only one of the two polarizations.

Also, red shift. 200 solar masses per second at the event equals
about 180 solar masses per second on Earth, as the event is receding
from us at about a tenth of the speed of light. Also, the received
frequency at the time of peak power, about 250 Hz, was originally
about 270 Hz. That's an impressive orbital period (1/270 second)
for two 30-solar-mass objects.

The last column is the number of gravitons per square meter per
second. I get that by multiplying the flux by the frequency and
dividing by Plank's constant.

Sigh. Of course I should have *divided* by the frequency, not
multiplied. So my estimated numbers of of gravitons were about five
orders of magnitude too high.

The total number of gravitons emitted by the event was about 3E+78.

I hope someone checks my math.
--
Keith F. Lynch - http://keithlynch.net/
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