Collision of two dead stars

It was a year of endings and beginnings: the plucky Cassini spacecraft’s 13-year-long mission reached its finale, while the fledgling field of gravitational wave astronomy bagged the catastrophic collision of two dead stars.

BBC News looks back on eight of the biggest science and environment stories of 2017.
Star crash

In 2017, scientists detected Einstein’s gravitational waves from a new source – the collision of two dead stars, or neutron stars. The first direct detection of these waves was announced in 2016, when the Advanced LIGO laboratories described the warping of space from the merger of two distant black holes. The result was hailed as the starting point for a new branch of astronomy, using gravitational waves to collect data about distant phenomena.

Telescopes from all over the world captured details of the neutron star merger as it unfolded. The outburst took place in a galaxy located roughly a thousand billion, billion km away in the Constellation Hydra. Some of the facts about these cataclysmic events are staggering. For example, neutron stars are so dense that a teaspoonful would weigh a billion tonnes. The team was also able to confirm that these collisions lead to the production of the gold and platinum that exists in the Universe.