How does LIGO detect gravitational waves?

How does LIGO detect gravitational waves?

LIGO currently consists of two interferometers, each with two 4 km (2.5 mile) long arms arranged in the shape of an “L”. These instruments act as ‘antennae’ to detect gravitational waves.

How far can LIGO detect gravitational waves?

All of this changed on September 14, 2015, when LIGO physically sensed the undulations in spacetime caused by gravitational waves generated by two colliding black holes 1.3 billion light-years away. LIGO’s discovery will go down in history as one of humanity’s greatest scientific achievements.

How does the LIGO detector work?

Gravitational waves cause space itself to stretch in one direction and simultaneously compress in a perpendicular direction. In LIGO, this causes one arm of the interferometer to get longer while the other gets shorter, then vice versa, back and forth as long as the wave is passing.

What does LIGO detect and measure?

LIGO’s multi-kilometer-scale gravitational wave detectors use laser interferometry to measure the minute ripples in space-time caused by passing gravitational waves from cataclysmic cosmic events such as colliding neutron stars or black holes, or by supernovae.

What has LIGO detected so far?

To date, LIGO has published the detection of gravitational waves generated by 10 pairs of merging black holes and two pairs of colliding neutron stars.

Can LIGO detect black holes?

LIGO and Virgo detect rare mergers of black holes with neutron stars for the first time. In a 3Q, Salvatore Vitale describes how gravitational-wave signals suggest black holes completely devoured their companion neutron stars.

How many countries have LIGO?

The LIGO Scientific Collaboration Established in 1997, the LSC includes over 1200 scientists from over 100 institutions in 18 different countries.

How many LIGO are there in the world?

A Nation-Wide Research Facility Although it is considered one observatory, LIGO comprises four facilities across the United States: two gravitational wave detectors (the interferometers) and two university research centers.

How powerful is the LIGO laser?

Each fiber carries 45 watts of laser power, so each bundle delivers 315 W (7 fibers x 45 W each) into each HPO rod to prime it to emit more and more laser light. By the time the beam exits the HPO it has finally achieved its desired power of 200 W.

How does LIGO detect black holes?

As an antenna able to detect vibrations in the ‘medium’ of space-time, LIGO is akin to a human ear able to detect vibrations in a medium like air or water. This is the way in which LIGO has opened a new ‘window’ on the universe. Things like colliding black holes are utterly invisible to EM astronomers.

How does LIGO use laser interferometry to detect gravitational waves?

The laser beams reflect back and forth off of mirrors, coming back to converge at the crux of the arms, canceling each other out. The passage of a gravitational wave would alter the length of the arms, causing the beams to travel different distances. The mismatch would be measurable with a light detector.

What was the strongest evidence for gravitational waves prior to direct detection with LIGO?

Before now, the strongest evidence of gravitational waves came indirectly from observations of superdense, spinning neutron stars called pulsars. In 1974 Joseph Taylor, Jr., and Russell Hulse discovered a pulsar circling a neutron star, and later observations showed that the pulsar’s orbit was shrinking.

Did LIGO prove gravity?

Einstein didn’t think humans would ever detect these ripples, called gravitational waves. But the Laser Interferometer Gravitational-Wave Observatory (LIGO) proved him wrong 100 years later. Now a global network of observatories has detected 50 probable gravitational waves from violent space collisions.