Evidence of dark matter- the motion of galaxies within clusters
Galaxy clusters are the leading bound formations in the cosmos. They are the best structure in which to view the impact of the dark matter. The dark matter occupies most of the space in the galaxy clusters. The dark matter is a gravitational mass, which is comprised of exotic elements that act very faintly with atoms and light (Matarrese & Gorini, 2010). Research done by scientists has revealed that the dark matter constitutes 23% of the mass of the universe.
In 1930, Fritz Zwicky observed that the movement of galaxies was not obeying the laws of gravity, which explained the existence of more matter in the galaxy cluster, which he could not observe through his telescope. Over the years, scientists have used advanced technologies to study dark matter phenomena.
The existence of the dark matter is a fact that scientists have proved. The proof for the existence of dark matter emerged from the discovery that several luminous bodies for example galaxies and stars, accelerate more than expected if they were under the influence of only the gravitational force of other visible bodies.
Fritz Zwicky discovered the gravitational effects of the dark matter while he was observing the motion of galaxies inside the Coma Cluster (Blain, 2005). Gravity holds the galaxies collectively into a cluster. Zwicky was in a position to find their masses using the derived velocities from the Doppler shift.
Moreover, Fritz also made calculations for the light production of the cluster. Through his study, he established that the light output of the cluster was much less that of the Kapteyn star (Matarrese & Gorini, 2010). His conclusion was that the Coma Cluster must have a significant quantity of matter not explained by the light of the stars, which he named the dark matter.
The features of the dark matter are clear when observing the collision of galaxy clusters. For instance, during the collision of two clusters, the dark matter in the two remains the same. However, the normal matter is under the influence of the normal matter and the dark matter of the other cluster (Blain, 2005). During the impact, the dark matter pulls forward the normal matter in its cluster. The overall result of the impact is to make the dark matter in the individual cluster to move ahead of the normal matter in the same cluster.
Scientific convincing evidence of the dark matter
Astronomers acquired convincing evidence of this scenario when they projected the Bullet Cluster experiment, which was a projection of two colliding galaxy clusters. They were able to manifest it through the discharge of visible light and x-ray (Matarrese & Gorini, 2010). The impact between the normal matters in each cluster heats the normal matter making the clusters to discharge x-rays.
Concurrently, the Bullet Cluster alters the images of galaxies that are at the back through the gravitational lensing effect. Through precise measurements of the altered galaxies, astronomers could evaluate the location and mass of every cluster. Galaxy clusters have more dark matter than normal matter; the lensing method provides the position of the dark matter, while the x-rays give the position of the normal matter (Blain, 2005). The image that links both the lensing and x-rays reveal that the dark matter is in front of the normal matter in both clusters, verifying the evidence.
Reference List
Blain, J. (2005). Progress in Dark Matter Research. New York: Nova Science Publishers.
Matarrese, S., Gorini, V. (2010). Dark Matter and Dark Energy: A Challenge for Modern Cosmology. Bristol: Springer Publishers.