Black holes are objects in space with gravity and density so strong, even light is unable to escape their grasp! Hence, the fitting name, black hole. Naturally, you might be asking yourself, “how do we know black holes exist?” After all, how do you “see” something that emits no light?
Without any visible light, our human eyes cannot see black holes. However, we can zero in on a black hole by watching how their powerful gravity affects things –– stars, gases –– around them.
For instance, a black hole’s powerful gravity would suck in gases from a nearby star. As the gases get sucked in faster and faster, it heats up tremendously, emitting radiation, like X-rays. We humans do have the ability to “see” X-rays by way of modern technology!
Plus, when large objects, like stars, approach the black hole, their orbiting speed changes. Scientists can observe and measure these speeds, helping them creating “chalk outlines” of where the black hole should be.
Currently, our hard evidence remains technically inconclusive. So how do we know black holes exist? Through observing their impact on surrounding matter and advanced technology, humans are getting closer to confirming black holes really do exist!