At first glance, a black hole is a bottomless pit. But what if it's like a perfect mirror, reflecting everything back? Such 'black mirrors' change the music of gravitational waves: stars falling toward them sound different. The difference in infall pace will reveal which is which once new detectors go live.
🎯 The Hawking temperature of a solar-mass black hole is just 60 nanokelvins—billions of times colder than the cosmic microwave background.