Astrophysicists Develop a Novel Approach for Searching for Dark Matter

The vast majority of the physical matter in the universe is dark matter, and we know very little about it. First coined in 1933, dark matter is the name given to a mysteriously invisible substance that permeates all galaxies but doesn’t interact with any scientific instruments, and so cannot be directly observed. It is indirectly detected by observing its gravitational pull on ordinary objects in space. A recent study pioneered a new method to indirectly detect dark matter in Jupiter’s atmosphere, bringing new hope to improving our understanding.

A small team of scientists searched archival infrared images of Jupiter taken with the Cassini spacecraft in 2000 for clues about dark matter. Since dark matter has never been directly observed, they searched for a byproduct, trihydrogen, or H₃⁺, which is thought to form when dark matter particles collide. Since Jupiter is so massive, the scientists expected it to attract lots of colliding dark matter, producing detectable H₃⁺ that the scientists call a “smoking gun” for dark matter detection. The team searched the Cassini images of Jupiter’s dark side for the signature glow of H₃⁺, but they did not detect anything above background levels. Although dark matter was not detected, the analysis placed a valuable upper limit on the size of dark matter particles. The team concluded that dark matter particles near Jupiter must have a collisional cross section lower than 10^-38 cm², corresponding to much greater sensitivity than laboratory experiments on Earth. The study paves the way for future detections as planets even larger than Jupiter in more dense dark matter regions like the inner galaxy could drive that sensitivity limit further down, increasing the likelihood of a detection.

This study serves as a reminder that the majority of the matter in our universe remains a mystery. Though the nature of the enigmatic dark matter remains elusive, we’re now armed with another tool to explore the unknown. The study also motivates future missions to look for dark matter in the atmospheres of planets beyond our solar system.

This study was led by Carlos Blanco, a postdoctoral researcher at Princeton University.

Managing Correspondent: Collin Cherubim

Press Article: Scientists use Jupiter to search for dark matter (Astronomy.com)

Original Journal Article: Search for Dark Matter Ionization on the Night Side of Jupiter with Cassini (Physical Review Letters)

Image Credit: GustavoAckles/Pixabay