On August 22nd, 2024, Liberty Science Center hosted Cara Giovanetti, Ph.D student in physics at New York University, for our latest Space Talk: “Dark Matter is Right Next to You”.

The contents of the Universe go far beyond just what we can see with our eyes. In fact, 80% of the matter in the Universe is made up of what scientists call dark matter – a mysterious substance that is totally invisible to our eyes. So, how do we study something that we cannot see and does not interact with light at all? In the country’s largest planetarium, Cara Giovanetti explored this question, and what her research is teaching us about how we can study dark matter.

Even though dark matter doesn’t interact with light, meaning light can pass straight through it, it does interact with the contents of the Universe through gravity. One way we can study dark matter is by closely studying clusters of galaxies like the Bullet Cluster, formed after two large clusters of galaxies collided with each other sometime in the ancient past. In this image, hot gas made of ordinary matter is shown in pink while dark matter is shown in blue. When these two clusters collided with each other, one coming in from the left of the image and the other from the right, the gas was slowed down by drag as gas from one cluster passes through gas in the other. On the other hand, dark matter was not slowed by the impact at all, and in fact simply passed through both the ordinary and dark matter in the cluster and has been separated from the ordinary matter. Clusters of galaxies like this provide some of the best laboratories in the Universe for astronomers like Cara Giovanetti to study the interactions of dark matter.

In the coming years we hope to learn more about this mysterious part of our Universe using new telescopes and observatories like the Vera Rubin observatory being built currently in Chile and other exciting technology to come.

Join us next month, on January 30, 2025, as we welcome Dr. Charles Liu, professor of astrophysics at the City University of New York's College of Staten Island, for our next space talk all about The Vera Rubin Observatory, the World's Next Great Telescope.