Have you ever wondered if there was something bigger than us out there? Have you ever imagined it was invisible? Maybe, but most likely not, right? Well, as science has theorized time and time again, there's something else out there. This something is dark matter. According to scientists, dark matter occupies about 25% of the universe. The rest is dark energy (which takes up about 70% (and visible matter (which takes up about 5%). It might seem like we know a lot about this thing we call Dark Matter, but we actually don't. Basically we know three things: there's something there, it interacts with gravity and there's a lot of it. Say no to plagiarism. Get a custom essay on "Why Violent Video Games Shouldn't Be Banned"? Become Original EssayYou're probably wondering, "What is it?" is dark matter?" Basically, it's an invisible substance that helps hold galaxies together. Let's look at some history During the 1960s and 1970s, astronomer Vera Rubin observed spiral galaxies. You can learn a lot about galaxies from the way they rotate. As he observed them, he noticed something unusually strange. The galaxies were moving at alarmingly faster speeds than expected. In 1600, John Kepler discovered that the further away a planet is from the sun, the slower it is orbit Later, Newton added numbers to this and found equations to find the mass of the sun by finding its gravity. You can't actually see the nebulae move, but you can measure their Doppler shift. Rubin expected nebulae to move in a pattern similar to that of solar systems. But what he found was that, even at the outskirts of galaxies, the speed was uniform or even faster. When you observe galaxies, you can clearly see fewer stars outside the galaxies. So the only way to make the equations work was if there was more matter. Scientists have nicknamed it Dark Matter. Over the years, experiments have only confirmed Dark Matter. Scientists listed everything they could think it might be. They thought of cold gas, dust, and dead stars. They thought of rogue planets and even strange subatomic particles. These particles were predicted to exist in theories of quantum mechanics, but had never been seen before. Scientists tested this dark matter to see if it emitted anything that normal matter would emit. Nothing was found, but they eventually crossed everything off the list. The only thing left were those crazy subatomic particles. There are many theories about what dark matter really is. Dark matter couldn't exist, for example. Many scientists believe it doesn't exist, but without it it simply doesn't add up. They could be MACHOs (MAssive Compact Halo Objects). These include black holes, brown dwarfs and neutron stars. Yet, there is too much dark matter for it to be all MACHO. They could be neutrinos, small subatomic particles that do not react with normal matter. Tens of thousands of them pass through you every second. However, they move faster than light, which would make them extremely hot. Furthermore, dark matter has been shown to move much slower than the speed of light. The next two theories are the most likely. Dark matter may actually be a subatomic particle called Axion. However, we have never been able to observe axions, which makes it very difficult to acquire evidence to support this theory. However, axions have all the same properties as dark matter and have mass, so a huge cloud of them would explain all the matter. They do not emit light and do not interact with normal matter. They cross it into?, 5(1), 12–19.