Scientists are searching for dark matter in gaps between stars

The Roman Space Telescope's simulated view over the Andromeda galaxy. Credit: NASA, NASA-GSFC, ASU, Robert Gendler DSS.

Imagine a universe filled with invisible matter that holds the key to many cosmic mysteries.

This is the world of dark matter, a mysterious substance that, despite making up about 27% of the universe, remains unseen.

But now, a group of international scientists, including experts from Northwestern University, are on the brink of a major breakthrough.

Their tool? The soon-to-be-launched Nancy Grace Roman Space Telescope by NASA.

Astrophysicists have been on a cosmic detective mission, looking for dark matter in the vastness of space. One method involves examining the “gaps” in streams of stars within our galaxy, the Milky Way.

These streams, often found in areas with few other structures, are so thinly spread that any disturbances might hint at dark matter’s presence. However, until now, this search has been limited to our galaxy.

With the Roman Space Telescope, set to launch by May 2027, researchers will be able to explore beyond the Milky Way, specifically targeting our neighboring Andromeda galaxy. This expansion of the search area is crucial.

It allows scientists to gather more data and better understand the properties of dark matter. Tjitske Starkenburg from Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Christian Aganze from Stanford University lead this groundbreaking study.

Dark matter is elusive. It doesn’t emit, reflect, or absorb light, making it invisible to us. So, how do we know it’s there?

Its presence is inferred from its gravitational effects on galaxies. For example, to explain how galaxies rotate, scientists need to assume there’s extra mass, possibly provided by dark matter.

The Roman Space Telescope is a game-changer. Positioned a million miles from Earth, it will capture images of stellar streams in nearby galaxies. These images will be 200 times larger and slightly more detailed than those from the Hubble Space Telescope.

Starkenburg, Aganze, and their team have simulated how dark matter clumps interact with star streams, creating detectable gaps. Their simulations suggest that the Roman Space Telescope could observe these gaps, offering new insights into dark matter.

The team’s work doesn’t stop there. They plan to study the halo of dark matter surrounding Andromeda.

Galaxies like ours and Andromeda are believed to be encircled by these halos. The researchers hope to detect smaller sub-halos, further enhancing our understanding of dark matter.

As we await the launch of the Roman Space Telescope, Starkenburg and her colleagues are developing a detailed theoretical framework.

They aim to predict how globular clusters form into stellar streams and whether these streams will be visible with the new telescope. This research could revolutionize our understanding of the universe, bringing us closer to unveiling the mysteries of dark matter.