What is a gravitational wave?
Rippling out from a super- massive collision, for example between two black holes, gravitational waves could be detected through the stretching and contracting of space and time
Spacetime
How Ligo and Virgo's detectors work
1
A single laser beam is split and directed down two identical tubes, 4km long
2
Mirrors reflect the twin beams back to a detector
2
Laser beam
Mirror
1
Detector
building
3
Back inside the detector, the laser beams arrive perfectly aligned
4
Recombined, they cancel each other out
3
4
No light is detected
Detecting gravitational waves
1
When spacetime is distorted by a gravity wave, the two tubes change length. One tube stretches as the other contracts over and over until the wave has passed
Contraction
Expansion
2
As the distances fluctuate the peaks and troughs of the two returning laser beams move in and out of alignment
3
The recombined waves no longer cancel each other out. Light reaches the detector and the gravitational wave can be measured
2
3
Light is detected
What is a gravitational wave?
Rippling out from a super- massive collision, for example between two black holes, gravitational waves could be detected through the stretching and contracting of space and time
Spacetime
How Ligo and Virgo's detectors work
1
A single laser beam is split and directed down two identical tubes, 4km long
2
Mirrors reflect the twin beams back to a detector
3
Back inside the detector, the laser beams arrive perfectly aligned
4
Recombined, they cancel each other out
2
3
Laser beam
Mirror
1
4
No light is detected
Detector
building
How are gravitational waves detected?
1
When spacetime is distorted by a gravity wave, the two tubes change length. One tube stretches as the other contracts over and over until the wave has passed
2
As the distances fluctuate the peaks and troughs of the two returning laser beams move in and out of alignment
3
The recombined waves no longer cancel each other out. Light reaches the detector and the gravitational wave can be measured
Contraction
2
Expansion
3
Light is detected