The universe, with its vast expanse, has long kept a secret: the whereabouts of a significant portion of its ordinary matter. Physicists have estimated that there should be much more observable matter than what we currently see in stars and galaxies. This missing matter has been a cosmic puzzle for decades.
However, a team of scientists from MIT, as part of the CHIME/FRB Collaboration, has made a breakthrough. They've developed a method to uncover this missing matter by combining the locations of galaxies with the detection of fast radio bursts (FRBs). FRBs, those ultra-bright, millisecond radio wave flashes, act as cosmic messengers, revealing the presence of matter as they travel through space.
The key lies in the smearing effect these signals experience. As an FRB travels, its signal gets stretched, and the more matter it encounters, the more it smears. By measuring this smearing, the team can determine the amount of matter the signal has passed through.
What they found was intriguing. The missing matter isn't just floating aimlessly; it's organized in diffuse clouds surrounding groups of galaxies. These clouds extend much further than previously predicted, almost like a cosmic halo.
"It's like discovering a new shape in the universe," says Haochen Wang, a graduate student at MIT. "We've found that missing matter tends to gather around galaxies, forming a kind of diffuse fountain."
This discovery supports the idea that matter is expelled from galaxies through energetic processes like black hole jets and exploding stars. Moreover, it suggests these processes are more violent than scientists initially thought.
"The universe is telling us that these events are more energetic and frequent than our models predicted," adds Kiyoshi Masui, an associate professor at MIT.
The team's method, by combining FRB data with galaxy locations, not only reveals the presence of missing matter but also its shape and distribution. This opens up new avenues for understanding how galaxies form and interact with their environment.
As CHIME continues to detect more FRBs, the team's method will only become more precise, offering a clearer picture of the universe's hidden matter. It's a fascinating development, shedding light on the universe's secrets one FRB at a time.
