What is Dark Matter?

Let’s start with the matter we know

Normal matter, also called Baryonic matter, surprisingly, only makes up about 5% of the universe's total mass-energy. Yes, it does sound insane that what we see every day conforms to only 5%…

The other ‘parts’ that make up the universe are Dark Matter (27%) and Dark Energy (68%). Today, we will focus on Dark Matter.

Dark Matter

Dark matter is similar to normal matter in that it occupies space and has mass. However, there is a key difference- it does not interact with light at all.

Well, if we can’t see dark matter, then how do we even know it exists? The answer lies in gravity!

Although light doesn’t interact with light, remember that it does interact with gravity, and hence we can see the effects of it indirectly.

How was Dark Matter found?

The first person to notice its effects was an astronomer named Fritz Zwicky, which was actually the first to also use the term ‘dark matter’. As Zwicky was studying the Coma galaxy cluster in the 1930s, we noticed how galaxies in the cluster were moving faster than they should be with the amount of matter that could be seen.

Later on in the 70s, another astronomer named Vera Rubin confirmed the existence of this so-called ‘dark matter’ and found that galaxies could perhaps contain invisible mass made up of dark matter.

Ok… but what even is it?

Well if you wanted a direct answer, I’m sorry to say that we currently don’t exactly know. But we do have hypotheses.

Dark matter is believed to exist as a kind of web structure that permeates the entire universe, a structure that attracts normal matter.

One idea is that dark matter is made up of supersymmetric particles, which are particles that are companions to the ones that are already known.

Another idea is the idea of a ‘Hidden Valley’, which is a parallel world that is made up of dark matter and not having much in common with the type of matter that we know about.

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