NASA has announced that the Hubble Space Telescope has detected the smallest known dark matter clumps using a new observation technique. The technique has confirmed that dark matter forms much smaller clumps than previously known. NASA says that the result confirms a fundamental prediction of the “cold dark matter” theory.
This theory says that all galaxies form and are embedded within clouds of dark matter. Dark matter is made of slow-moving or “cold” particles that come together to form structures that can be as large as hundreds of thousands of times the mass of the Milky Way galaxy to clumps that are about the mass of a commercial aircraft.
NASA says that the Hubble observations give new insight into dark matter and how it behaves. Dark matter is an invisible form of matter that makes up the bulk of the universe’s mass and creates a scaffolding that galaxies are built on. The challenge with detecting small amounts of dark matter is that they contain few stars making looking for embedded stars difficult or impossible.
The technique that the Hubble team used didn’t look for the gravitational influence of stars as an indicator of dark matter. The team instead targeted eight quasars that orbit black holes. The light coming from the gas orbiting each of the black holes is warped by the gravity of the foreground galaxy and acts as a magnifying lens.
The team was able to uncover dark matter clumps along the telescope’s line of sight to the quasars as well as in and around the intervening lensing galaxies. The team notes that the eight quasars and galaxies were aligned precisely enough that the warping effect produced four distorted images of each quasar.