Matter is something that we can perceive with our eyes,ears,nose and so on. But, what is Dark matter? Why do we call it dark matter and again what is it? Let us just say that Ajax kidnapped you and is experimenting on you. At first, he gives you something, something that has no taste,which is invisible and you can't see it. So what was this unknown thing? This was called Dark matter because scientists thought it was a really fancy name. But how do we know they exist?Well here's how.
When we calculated the entire mass of a single galaxy there just wasn't enough mass in the galaxies to form galaxies.The gravity of the normal matter was not enough to hold suck complex and large "stuffs".So we knew there was something else there, something which could not be seen with the naked eye something invisible.
Dark matter can be seen with some fancy telescopes and all those thing [JP]. Remember when I told you that we can't see it? Well I lied, we can see it. As we know that Dark matter has something to do with gravity.So places with high concentration of dark matter can bend light and this is one of the ways of finding what Dark matter is.Dark matter is normal matter but with some special abilities.If this strange thing did not exist then we probably should be dead by now.
Well here is a little question for you If Dark matter is normal matter with some kind of super abilities what are it's constituent parts( Just like an atom i.e. electrons, protons and neutrons )?