... like I'm 5 years old
Black holes are fascinating structures in space that have been a source of intrigue and study for scientists. At its core, a black hole is an area in space where gravity is so strong that nothing can escape, not even light. This is why they're called 'black' holes, because they absorb all light. They're formed when a star collapses under its own gravity after it has burned all its fuel.
Imagine you're trying to climb a hill that keeps getting steeper and steeper. At some point, the hill becomes so steep that you can't climb up anymore and you slide down. Now, imagine that instead of a hill, you're trying to escape the pull of gravity from a black hole. The gravity is so strong that it's like the steepest hill you can imagine - nothing can climb out, not even light.
A black hole is like a cosmic trapdoor; once something falls in, it can't come out.
... like I'm in College
Black holes are regions of spacetime exhibiting gravitational acceleration so strong that nothing, including particles and electromagnetic radiation such as light, can escape from inside it. In many ways, a black hole acts like an ideal black body, as it reflects no light.
They are formed from the remnants of large stars that explode as supernovae at the end of their lifecycle. Once formed, they continue to grow by absorbing mass from their surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form.
There is a boundary in space around a black hole called the event horizon. If anything crosses this boundary, it can never come back out as it's now within the black hole's gravitational grasp.
Imagine a large flat Lego baseplate. This represents the fabric of space. Now, place a heavy Lego structure in the middle of the baseplate. You'll see the baseplate bend under its weight. This is how a star distorts space.
When the star collapses and forms a black hole, it's like replacing the heavy Lego structure with an even heavier one. The baseplate bends so much that it forms a deep well. This well is so deep that any Lego piece that rolls near it falls in and can't roll back out.
Even if you use a Lego piece representing light (say a glowing Lego brick), and try to roll it really fast across the baseplate, it will still fall into the well if it gets too close. That's the event horizon.
The bottom of this well is the singularity, the center of the black hole. But remember, this is a 2D analogy. In reality, black holes are 3D and distort space in all directions.
A black hole is like a deep well in the fabric of space. Once something falls in, it can't climb out.
... like I'm an expert
Black holes are fascinating not just because of their extreme gravity, but also because they warp space and time, a concept put forth by Albert Einstein's theory of General Relativity. The very center of a black hole, called a singularity, is where the laws of physics as we know them cease to operate.
Researchers use concepts like the 'No Hair' theorem to describe black holes, which posits that all information about the material that formed a black hole or that has fallen into it, is lost, leaving behind only mass, electric charge, and rotation.
One of the active areas of research is the study of 'Hawking Radiation', a theoretical prediction by physicist Stephen Hawking. It suggests that black holes are not entirely black, but emit small amounts of thermal radiation due to quantum effects near the event horizon.