Chapter 3 - The Big Bang

While studying the Big Bang and the aftermath, scientists soon discovered that most of the universe was not made up of familiar atoms but mostly substance called “dark matter.” Dark matter weighs approximately10x more than normal matter.

In the 1930s, a Swiss astronomer, Fritz Zwicky, noticed that the Coma cluster of galaxies were not moving according to Newtonian gravity. He saw that the galaxy was spinning so fast it should fly apart and dissolve. He suggested that the only the cluster was not being ripped apart was if it had hundreds of times more matter than what was seen by the telescope. In 1930, either Newtonian laws were incorrect or there was a huge amount of invisible matter in this cluster holding it together.

Nobody believed Zwicky and so the theory of dark matter was abandoned until 1962 when astronomer Vera Rubin noticed that the Milky Way was experiencing the same problem. According to Newtonian Laws, the Milky Way was missing 90% of its mass. Since so much mass was missing, Rubin knew that there must be some other form of matter that takes up the extra mass. Unfortunately, Vera was a girl, and so she was ignored until 1978, when a man, Albert Bosma, published an analysis showing that Rubin had been right all along, and “dark matter” does exist.

Dark matter has now been mapped out over the entire universe. From the picture on the left, we can see that dark matter clumps together, and over time it is getting closer and closer together. Not shown in this picture, but has been observed by telescope is that matter tends to form it self on top of dark matter, meaning that there is more matter wherever there is more dark matter.

The theory of dark matter intrigued me because it is invisible mass. It coexists with us, but we cannot interact with us. It controls the movement of our galaxy yet we know so little about it. We don’t know what it is made of, but it has been speculated that it is made of brown dwarf stars, neutron stars and even black holes. All of these are nearly invisible to us which is why we can’t see dark matter.

Interestingly, some scientists disagree, and think that dark matter is made of a an entirely new type of matter called “cold dark matter” or “weakly interacting massive particles.”

We know very little about dark matter, but it is speculated that it accounts for 22% of the mass of the universe. Observable mass/energy, or the matter that we can see accounts for 4% of the mass leaving 74% of the mass of the universe to “dark energy” which is even more interesting than dark matter. Dark energy being the energy of nothing or the repulsive form of gravity.

By learning more and more about what our universe is made we realize that we actually know less and less about the universe. We don’t even understand what makes up 74% of the energy in our universe. We realize that we have a far way to go in understanding what really is going, and makes us wonder if we’ll ever know what is really controlling us.

To learn more about the picture, how scientists created the picture, or to learn more about dark matter, please watch this video. It is only three minutes, but it will be worth your while.