MIT Builds Huge Space-Time Ripple Detector

Scientists at MIT just launched a new search for the waves of the Big Bang rippling through the universe. The plan is for a huge, sensitive, new-generation gravitational-wave detector. Over the following three years, the National Science Foundation will be constructing it.

This huge and extremely sensitive gravitational-wave observatory will be as large as a small city. Scientists hope to be able to pick up small ripples in space-time from the early universe.

The detector will measure the timing of two lasers made to travel from the same point down two separate tunnels and back. Any difference in their arrival times could be a signal that a gravitational wave passed through.

There already is a Laser Interferometer Gravitational-Wave Observatory (LIGO) that MIT and Caltech operate in, and this one will be similar but ten times larger.

The arms of the new L-shaped detector will stretch out forty kilometers on either side and be ten times larger than the ones in the observatories today. They will be able to pick up gravitational ripples from much further away. This will shed light on many more ancient events that created enough energy in the past to also produce gravitational pull.

Scientists have also replicated the sound of a black hole, as well as the sound of the gravitational ripples, making moves towards applying the theory of general relativity to empirical observation.

Discoveries in Gravitational Ripples

It is being hoped that this type of detector will identify events that created so much energy so as to also bend space-time through gravity.

One such event is the collision of neutron stars, made of the densest stable matter in the universe. This can result in the creation of a black hole—that is, unless the stars reach certain mass beyond which their own mass and density creates black holes. This is determined by the Tolman–Oppenheimer–Volkoff limit.

The impact creates a shock that sends gravitational ripples. These were first detected in 2015 and studied the following years to measure and understand what kinds of objects created those ripples.

The scientists concluded that among the first events that were detected by LIGO were two black holes colliding. They were able to calculate the speed at which the black holes collided and the energy that was generated as a result. LIGO has had two twin detectors in different parts of the United States. Other similar detectors operate in Italy (a set of them called Virgo), and another set is KAGRA in Japan.

As the building of several similar detectors over the world has greatly advanced the research, with more ripples detected and further away, this is not enough. Scientists are trying to build an even more sensitive instrument that might be able to tell us what happened when the galaxies started forming.

Cosmic Explorer’s executive director, Matthew Evans and his colleague Salvatore Vitale, are ready to see the new detector in action. They are already studying the collision of black holes and neutron stars as far back as 1.4 billion light years away. This is far, but not enough in comparison to the size of the universe.