What Is Ordinary Matter and Why It Matters
The universe contains two types of matter. One is invisible dark matter, detected only by its gravitational pull. The other is ordinary matter—everything from stars and planets to gas, dust, and even items like biscuits or boats. Surprisingly, ordinary matter makes up just 15% of all matter in the universe. Scientists have known this for years, yet half of it remained missing—until now. A team of researchers has finally tracked it down using fast radio bursts, or FRBs.
Discovering the Hidden Ordinary Matter Between Galaxies
Fast radio bursts are strong pulses of radio waves that travel through space. They originate from faraway points in the universe and can last just milliseconds. As these waves move through space, they interact with matter. This interaction changes the radio waves’ properties, allowing scientists to measure the amount of material they pass through.
Researchers studied 69 FRBs, including 39 found with Caltech’s Deep Synoptic Array, a group of 110 radio telescopes in California. Some of these FRBs came from sources as far as 9.1 billion light-years away—setting a new distance record.
The data showed that most of the missing matter exists as a thin, spread-out gas called plasma. This gas fills the space between galaxies, known as the intergalactic medium. It is almost like a cosmic fog that surrounds the universe.
Tracing Matter Across the Universe
According to the findings, 76% of ordinary matter lies in this intergalactic medium. Another 15% exists in the halos—outer regions of material—around galaxies, including the Milky Way. The remaining 9% is found inside galaxies, mostly as stars and gas.
This matter is made of baryons, which include subatomic particles like protons and neutrons. These particles are the building blocks of atoms and are present in everything we see and touch.
So, why is so much of this matter located in space between galaxies? Events like supernova explosions and activity from supermassive black holes can blast huge amounts of gas out of galaxies. These violent bursts push matter far into the cosmic wilderness.
Unlocking More Cosmic Mysteries
Professor Liam Connor from Harvard University led the study, published in Nature Astronomy. He explained that finding the missing matter was crucial. Now that scientists know where it is, they can focus on deeper questions—such as the true nature of dark matter.
Connor added, “We know what ordinary matter is, but dark matter remains a mystery. We can now turn our attention to understanding this invisible substance.”
With this breakthrough, researchers are better equipped to explore the universe’s remaining secrets.
with inputs from Reuters
