Explanation:
A new sky is becoming visible.
When you look up, you see the sky as it appears in light --
electromagnetic radiation.
But just over the past year, humanity has begun to see our once-familiar sky as it
appears
in a different type of radiation --
gravitational radiation.
Today, the
LIGO collaboration is
reporting the detection of GW151226,
the second confirmed flash of gravitational radiation after
GW150914,
the historic first detection registered three months earlier.
As its name implies, GW151226 was recorded in late December of 2015.
It was detected simultaneously by
both LIGO facilities
in
Washington and
Louisiana,
USA.
In the
featured video,
an animated plot demonstrates how the frequency of
GW151226 changed with time during measurement by the
Hanford, Washington detector.
This GW-emitting system is best fit by
two merging black holes
with initial masses of about 14 and 8 solar masses at a
redshift of roughly 0.09,
meaning, if correct,
that it took roughly 1.4 billion years for this radiation to reach us.
Note that the brightness and
frequency -- here mapped into sound -- of the
gravitational radiation
peaks during the last second of the black hole merger.
As LIGO continues to
operate,
as its sensitivity continues to increase, and as
other gravitational radiation detectors come online in the next few years, humanity's
new view of the sky will surely change humanity's
understanding
of the universe.
