Scientists target super-massive black holes

An artist's view of a black hole in a globular cluster NASA/Space Telescope Science Institute/Reuters

A team of astronomers led by Lucio Mayer from Zurich University believe they have discovered how and when the universe’s first super-massive black holes were born.

The discovery, published in Nature magazine, could help scientists understand how gravity and dark matter formed the universe.

Black holes are objects in which the pull of gravity is so strong that nothing, not even light, can escape. They are detected by the effect they have on their surroundings.

Super-massive black holes can have masses of millions or even billions of solar masses and inhabit the centres of galaxies. A black hole of four million solar masses is thought to sit at the centre of the Milky Way.

Our universe is thought to be 14 billion years old and galaxies came about within the first billion years.

Using computer simulations, Mayer and his team found the first super-massive black holes were probably born when those early galaxies collided and merged together, around 13 billion years ago.

Prevailing wisdom had been that galaxies evolved hierarchically – that gravity drew small bits of matter together first and these gradually came together to form larger structures. The team’s results show the opposite – that big structures like galaxies and massive black holes built up quickly.

This has to do with the fact that dark matter grows hierarchically and ordinary matter, which makes up visible galaxies and super-massive black holes, doesn’t, the scientists explained.

The team hope that their work will help researchers looking for evidence based on Einstein’s theory of general relativity, in which any ancient galaxy mergers would have created massive gravitational waves, whose remnants should still be visible.

swissinfo.ch