For the first time, scientists have directly detected gravitational waves—ripples in
space and time—in addition to light from the spectacular collision of two neutron stars.
This marks the first time that a cosmic event has been viewed in both gravitational waves
and light.
The discovery was made using the U.S.-based LIGO, the Europe-based Virgo detector; and
some 70 ground- and space-based observatories.
For the first time, Astronomers have
detected a single cosmic Cataclysm in
both gravitational waves ripples in
space-time itself and electromagnetic
waves what we typically call light.
This
hugely collaborative effort includes the
LIGO and Virgo gravitational wave
Observatories along with a multitude of
telescopes in space and on earth that
together collectively monitor the full
spectrum of light.
The spectacular event
was produced by the collision and merger
of two neutron stars.
These objects are
the burnt-out remains of giant stars
that have exploded as supernovae they
leave behind cores of exotic matter
composed primarily of neutrons crushed
together under the intense pull of
gravity more mass than our Sun is
compressed into a sphere that is about
the size of a city.
Astronomers have long
known that neutron stars are found in
pairs orbiting one another.
The theory of
relativity predicts that the motions of
these incredibly massive objects should
generate gravitational waves these waves
would drain energy from the orbiting
bodies causing them to slowly spiral
together and eventually collide with
each other in a spectacular explosion.
On
August 17th 2017 a gravitational wave
chirp was recorded by the National
Science foundation-funded LIGO
observatories and less than two seconds
later a short burst of gamma rays a
high-energy form of light was detected
by NASA's Fermi telescope researchers
quickly realize these two fundamentally
different types of ways could have come
from a single neutron star merger if so
it was critical to identify exactly
where this had taken place in the sky
and if the explosion could be seen by
other telescopes the Fermi data
indicated the bursts came somewhere from
a patch of sky covering about 1200
square degrees an area equivalent to six
thousand four moons
adding information from an independent
gamma-ray detection from the integral
satellite the search area was further
reduced the LIGO observatories place the
source somewhere in long narrow strips
of the sky
one of which overlapped with a target
patch the Virgo gravitational wave
Observatory in Italy working in
conjunction with LIGO should easily have
been able to detect the signal of the
strength but saw almost nothing this was
an important piece of the puzzle since
any gravitational wave observatory has a
small number of blind spots where it
cannot detect the incoming signal
restricting the source location of
virgos blind spots further narrow in the
search area down to approximately twenty
eight square degrees or 144 moons around
50 candidate galaxies were identified in
this area for follow-up observations
using optical telescopes less than 11
hours after the first detection z'
astronomers using the carnegie Swope
telescope identified a previously unseen
blip of light in the outer reaches of
the galaxy named NGC for 993 several
independent confirmations will report it
from other telescopes over the next hour
the first-ever optical counterpart to a
gravitational wave event had been found
knowing exactly where to look
astronomers began an unprecedented
campaign of follow-up observations using
more than 70 telescopes around the world
in the space during the course of the
next two weeks a neutron star merger was
detected across the entire
electromagnetic spectrum the
gravitational wave data have for the
first time provided a direct measurement
for the masses and orbits of a neutron
star pair before their collision and
merging the data also enabled ongoing
follow-up observations across the
electromagnetic spectrum characterizing
the explosion and revealing how such
unimaginable events have played a
formative role in shaping the world
around us these results for the first
time confirm that neutron star mergers
create precious elements like gold and
platinum as well as a host of other
heavy elements all across the periodic
table
explosions like these through our cosmic
history have seeded the universe with
the materials that later will form new
stars new planets and beings like
ourselves who look up and wonder