Physicists detected gravitational waves for the second time ever

It was one of the biggest moments in recent memory when an international team of physicists announced that they’d made the first direct observations of gravitational waves since Einstein first proposed them a century ago.

Now, just four months later, an Australian team has announced the second such achievement - they’ve directly detected gravitational waves caused by the collision of two black holes that are up to 14 times the size of our Sun.

Visible light emitted from a black hole has been detected for the first time

For the first time, astronomers have observed bursts of visible light being released by a black hole as it swallows matter from nearby stars.

These flashes of light, which lasted between several minutes to a few hours, were seen coming from a black hole in the Cygnus constellation, located about 7,800 light-years away from Earth. Incredibly, some of the flashes were so bright, the team says amateur astronomers could see them with a modest 20-cm telescope.