Stuart A. Sim

Out in the distant cosmos, there are galaxies that astronomers have nicknamed 'little red dots': in images they appear as tiny reddish specks, even though they are mind-bogglingly far away. Their light looks red not because they are cold, but because the expanding universe stretches light waves.

When two neutron stars collide, they produce a flare that shines like a million Suns. In 2017, astronomers saw such a flare for the first time — event AT2017gfo. Now scientists have built computer models to understand exactly how this light arises.