Astronomers have at last found the universe’s missing ordinary matter, the particles that formed in the first few minutes after the Big Bang and that account for everything we see around us, from the Earth to the stars. Some fast radio bursts (FRBs), vanishingly fast, hugely energetic signals from deep space, have allowed scientists to finally detect some of the missing normal matter that had eluded them for decades. 

Fast Radio Bursts Reveal Hidden Baryonic Matter Spread Across Vast Intergalactic Cosmic Fog

According to a mission update published in Nature Astronomy, researchers from Caltech and the Harvard-Smithsonian Centre for Astrophysics looked at 69 FRBs, some of which travelled up to 9.1 billion light-years, to find baryonic matter that is spread out in the space between galaxies. Using instruments like Caltech’s Deep Synoptic Array and Australia’s ASKAP helped the research locate and home in on the FRBs, which are too small for regular sensors to detect.

So there is a type of missing matter that has been found: It is made of particles, of course, but we interact with those particles only secondhand, via the almost unimaginably infrequent creative collision. FRBs, the cosmic headlights, have validated this by revealing baryonic matter — 76 percent in the inter­galactic, 15 percent in galactic haloes, and 9 percent within galaxies — to be distributed much more uniformly in space compared to dark matter.

The first observational evidence of this distribution that they predicted has been obtained, indicating that the FRBs can be used as a “smart tool” to probe the large-scale structure and the evolution history of the universe. This light distortion seen from these bursts is now a new tool to explore the faraway areas in space.

Caltech’s DSA-2000 radio array could detect more than 10,000 FRBs every year, which would significantly advance the field of radio astronomy. This could provide a way to better understand the formation and evolution of galaxies and to more accurately measure cosmic structures. Every new FRB is a new chance to fill in the map of the unknown universe.