What is that black stuff we see when we look at the stars in the sky? Empty space? Nothingness? It is not always what’s seen in the light, but what hides in the dark. Apart from black holes, one of the most interesting things about our universe is something called “dark matter.” In theory, dark matter is that black stuff you probably never thought about before. The catch is, we aren’t exactly sure what it is, we just know it is there and it is .. something? That is why it is so awesome! It cannot be seen with the naked eye or telescope, and it neither reflects nor emits light. Observing something you can’t see is not an easy task. For something that we know next to nothing about, it constitutes a large portion of space; estimated 84% of the universe.
Proof that this is something real? We have no solid evidence, just hints. Everything is supposed to be made of atoms or particles right? Well, we have yet to find any dark matter particle. If there is no real proof then, why does the dark matter theory exist? The idea first came about when cosmologists started to estimate the masses of certain galaxies about a decade or go. When this mass was compared to the mass of all the objects we can see, there is still some left over. Personally, I’m not convinced based on just an estimate of a galaxy’s mass, one can never know this measurement truly. However, according to Einstein and the laws of physics, gravity causes objects closer to be exposed to more gravity than objects farther away. Now, for planets that would mean Mercury orbits the sun slower than Venus. The crazy thing is this does not actually happen. All the planets in our galaxy orbit at a constant speed. There is something else emitting a gravitational pull to cause this to happen. If not, our home galaxy would fall apart and be flying all over the place. So, according the indisputable rules of mother nature, there has to be more mass in our galaxy than what we see. Actually, about 10x more matter we cannot see versus what we can.
If that isn’t convincing enough, a technique was developed called “gravitational lensing.” Simply put, every type of matter bends light. Using this science, researchers found that light was being bent off of nothing. But.. light does not just bend by itself, that is literally impossible. Matter must exist within that dark space. There is an endless amount that one can write about dark matter, and believe me I plan on it, so consider this an introduction.
There is more than meets the eye.
Space Vagabond 