Dark matter (not to be mistaken with dark energy) makes up about 27% of the universe. Unlike normal matter, dark matter does not interact with electromagnetic forces. This means it does not absorb, reflect or emit light, therefore it can't be seen, but researchers can detect it and map it by measuring gravitational lensing. Because of these properties, it works like an attractive force, holding the universe together.
In the 1930s, astronomer Fritz Zwicky studied images of around 1,000 galaxies that make up the Coma Cluster and speculated that some kind of matter must be keeping them together. Astronomers Vera Rubin and Kent Ford found a similar phenomenon when they studied the rotation rates of individual galaxies, with even more evidence of the features mentioned above.
The existence of dark matter is so widely accepted that it’s part of the "standard model of cosmology", although there is no solid evidence that it is real. There are many theories suggesting that physics beyond the Standard Model, such as supersymmetry and extra dimensions, exist. If other parallel universes exist, then physical features of each universe would be different, therefore the amount of dark matter in each universe would be different. Dark matter helps scientists gain a better understanding of the composition of our universe and how galaxies are held together.
Sample Sentence(s):
"You can see the galaxy clusters that Professor Zwicky studied to discover Dark Matter."
"Dr. Shepherd's work enhances our profile in the area of Dark Matter exploration significantly."
