Black Holes, on their own, are not exactly space anomalies. We know they exist and we know what they can do for the most part. However, even that can be called into question. Black Holes still surprise us from time to time. To understand exactly what a Black Hole actually is, you should first know that it involves time and gravity. We know from Albert Einstein’s Theory of General Relativity that gravity will often help us dictate time. Black Holes are a region of spacetime where the gravity is so impressively strong that absolutely nothing, even radiation & light, can escape. We found using Einstein’s equations that properly compact mass can deform spacetime, allowing the emergence of a Black Hole.
This usually tends to occur when massive stars collapse as they die off. Once one forms it can grow by absorbing more mass and even by merging with other black holes. Supermassive Black Holes are said to likely exist at the center of most galaxies. Yet this is roughly what we know. We have no idea what happens when you’re fully sucked in. We know that it will bend and break whatever it absorbs but we do not know what happens once something is fully sucked in. Does it come out somewhere else? Where does this mass absorbed actually go in the end? These are the questions science may never have a true answer to, making them essentially anomalies to us.