You never really know what you might find hiding in your own backyard, especially if those things are particularly adept at escaping detection. Just 1,924 light-years from the Solar System, in the constellation of Aquila, astronomers have just discovered a black hole. And it's not just any black hole. Named Gaia BH3, or BH3, the object is the most massive stellar-mass black hole we've ever spotted in the Milky Way, clocking in at a hefty 33 times the mass of the Sun. It's the second-closest black hole we've found to our home-world, and it's just hanging out, quietly in space,...