Dark matter, also known as the elusive substance that makes up the majority of our universe, has been baffling scientists for quite some time. It’s remarkable to think that dark matter dominates our universe and yet remains completely invisible to us. So, what exactly is dark matter?
The Dominance of Dark Matter
Dark matter comprises about 85 percent of all the matter in the universe and approximately 27 percent of the total energy and mass of the universe. That’s an enormous amount when you consider that we can’t even see it.
The First Discovery of Dark Matter
The story of dark matter’s discovery began in 1933 when a Swiss astronomer named Fritz Zwicky conducted research on the movement of galaxies within the Coma Cluster.
Zwicky was comparing the mass of galaxies with their orbital velocities. He hoped that this study would prove that the amount of gravity pulling galaxies toward the center of the cluster would determine how fast they rotate.
However, what Zwicky found was rather puzzling. Galaxies on the outer edges of the cluster were moving too fast for gravity to explain. This raised a significant question: what was keeping these galaxies in place?
The First Theory of Dark Matter
Zwicky calculated mass using the number of galaxies and their estimated brightness in the cluster. However, the results did not match the required gravitational force. As a result, he theorized that there must be unseen mass at play.
This invisible mass was termed “Dunkle Materie” or dark matter by Zwicky. He described dark matter as having a peculiar characteristic: it couldn’t be seen and didn’t reflect light, but it had gravitational mass.
Evidence for the Existence of Dark Matter
The existence of dark matter has been proven through observations of collisions between galaxy clusters. For example, in the case of the Bullet Cluster, two galaxy clusters collided, with the smaller cluster, known as the Bullet Cluster, passing through the larger one.
During this collision, the hot gas within the clusters emitted X-rays and was considered normal matter that we can see. However, when the gravitational effects were measured, it was found that there was additional unseen mass dominating the colliding clusters.
This aligns with Albert Einstein’s General Theory of Relativity, which states that mass affects the space-time fabric, leading to what we perceive as gravity. Even though we can’t see it, this mass can be felt through its influence on light.
The Origin of Dark Matter
Many scientists believe that dark matter consists of non-baryonic matter, which is the opposite of the ordinary matter we can see. One primary candidate for dark matter is something called Weakly Interacting Massive Particles (WIMPs).
WIMPs are thought to have a mass between 10 to 100 times that of a proton, but because they interact weakly with other particles, they are incredibly challenging to detect. Scientists are continuing their research to unveil the true nature of dark matter through experiments at facilities like the Large Hadron Collider.
Dark matter, the enigmatic component that remains invisible in our universe, makes up the majority of its mass. Ongoing research and observations help us understand the role of dark matter in the dynamics of the universe and how it influences our lives here on Earth. As we delve deeper into the mysteries of dark matter, we may uncover even more about the secrets of our cosmos