Apparently, you can learn a lot by watching a black hole eat.
In 2014, astronomers spied a supermassive black hole nearly 300 million light-years away gobbling a star, an event known as a tidal disruption flare or TDE. Given the rarity of such a spotting, they’ve kept a close eye on it ever since.
The hope was that it would teach them something new about how black holes feed. But it ended up teaching a team at the Massachusetts Institute of Technology something else: a new way to measure how fast a black hole is spinning.
The MIT team describes its discovery Lees verder