The universe is a mysterious place, and scientists are constantly uncovering new insights into its workings. One of the most intriguing phenomena is the concept of dark matter, an invisible substance that makes up a significant portion of the universe's mass. But what about the other side of the cosmic coin? What about the ordinary matter that makes up the rest of the universe? It turns out that a large amount of this ordinary matter is missing, and scientists are now on the hunt to find it.
The missing ordinary matter is a fascinating topic that has been the subject of much research and debate. It's a complex issue that requires a deep understanding of the universe's history and the behavior of matter. To shed some light on this topic, I spoke to Liam Connor, an assistant professor of astronomy at Harvard University, who is researching fast radio bursts and AI in astrophysics, and building large radio telescope arrays.
Connor explains that when astronomers talk about normal matter, they're referring to baryons, or the stuff of atoms, such as protons and neutrons. But when they count the stars, planets, and dust they can see with telescopes, they find a significant amount of matter appears to be missing. This missing matter is not just a theoretical concept; it's a real, observable phenomenon.
The missing matter is hiding in plain sight, in a diffuse state called the intergalactic medium. This medium is a kind of wispy, fuzzy cosmic web that surrounds galaxies. It's a challenging place to find matter, but Connor and his team have used fast radio bursts (FRBs) to help them locate it. FRBs are pulses of radio waves that last around a millisecond, and they can be observed billions of lightyears away.
The team uses radio telescopes to pinpoint the location of FRBs and then follows them up with optical telescopes. This process gives them a fingerprint of the galaxy, telling them what type of galaxy hosts the FRB and how far away it is. By analyzing the data, they can determine the average density of normal matter in the universe. A sample of 50 or 100 FRBs can provide valuable insights into the location of the missing matter.
The implications of this discovery are far-reaching. The most interesting aspect of the research is not that they found the missing ordinary matter, but that this matter was contained outside of galaxy haloes. When galaxies form, they slosh matter around in a process called feedback, which smooths out the matter in the universe. This feedback process is strong and efficient, and it has a significant impact on the distribution of matter.
The team's findings have opened up a host of new questions and possibilities. What is the distribution of gas in the universe, and how does it relate to the growth of supermassive black holes? How does this feedback process affect the precision of cosmology? These questions and more will be explored as the team continues its research.
The search for the missing ordinary matter is a fascinating journey that has the potential to revolutionize our understanding of the universe. It's a testament to the power of scientific inquiry and the endless mysteries that await discovery in the cosmos.
