Physicists are searching in a sea of gravitational waves for the first stars in the universe, which were able to grow much heavier than their descendants.
When terrestrial experiments pick up gravitational waves, so far they have always come from one specific event. Two heavy objects – usually black holes – merged somewhere far away in the universe, creating vibrations in spacetime. Vibrations that we have been measuring with some regularity since 2015, thanks to detectors like LIGO in the US and Virgo in Italy.
But physicists and astronomers expect that before too long we will not only be measuring these kinds of waves, but also a sea of gravitational waves that cannot simply be traced back to separate collisions: the gravitational wave background. And in that sea might be hidden evidence for the first stars in the universe, which were able to become much heavier than their distant descendants. But can that evidence be fished out of that sea? That is the question that physicist Katarina Martinovic of King’s College London, together with three colleagues, tackled.