A Huge Part of the Universe Is Missing—Scientists Think They Finally Found It!

[00:00:00]Despite existing on a small planet in a tiny corner of the cosmos, astronomers know exactly how much visible matter the entire universe should contain. The problem is that for decades, 40% of it has been missing. And I'm not just talking about the ever mysterious dark matter and dark energy. Galaxy clusters don't seem to have as much visible mass as our models say should be there.

[00:00:24]Entire galaxies seem to have lost huge reservoirs of the material they were born with.

[00:00:29]Even the space between galaxies, enormous cosmic [music] deserts, are emptier than our best theories predict.

[00:00:37]This missing mass has to be out there.

[00:00:40]That or all our models of cosmology are wrong. For decades, scientists searched with their most powerful telescopes, but the missing matter remained hidden until now. A new study may have finally uncovered its trail using some of the shortest and most mysterious signals in the cosmos. Fast radio bursts. These flashes last only milliseconds. Yet something happened to them while they traveled across billions of light years.

[00:01:10]Hidden inside that tiny change was a clue to one of cosmologyy's biggest mysteries. And when astronomers followed it, the answer pointed somewhere far more unexpected than they imagined.

[00:01:25]>> [music] >> To understand why this discovery matters, we must return to the beginning of the universe. Around 380,000 years after the Big Bang, space cooled enough for light to travel freely. That ancient light still surrounds us today as the cosmic microwave background. Tiny patterns within it allow astronomers to calculate how much ordinary matter the early universe contained. This ordinary matter is known as berionic matter. It includes protons and neutrons, the building blocks of atoms, stars, planets, [music] and everything we can physically touch. According to those early measurements, all that matter should still exist today. Atoms do not simply disappear from the universe. But when astronomers tried to locate them, the numbers refused to balance. Stars contained only a small fraction. Adding planets, dust, cold gas, and the material inside galaxies still left a huge gap. Researchers found more matter in hot gas surrounding galaxies and galaxy clusters. But even that was not enough.

[00:02:35]Somewhere between the young universe and the present day, an enormous amount of ordinary matter had apparently vanished.

[00:02:42]The leading theory was that it had not disappeared at all. Instead, it may have become extremely hot, thin, and ionized.

[00:02:50]In that state, electrons separate from atoms, creating a faint plasma spread across enormous distances. A cloud on Earth can easily block light, but spread that same amount of material across millions of light years and it becomes almost impossible to see. This was the problem confronting astronomers. The missing matter could be directly in front of them yet remain too diffuse to shine brightly or cast an obvious shadow. The scientific paper describes this material as extremely low density and almost completely ionized, making conventional observations [music] exceptionally difficult. Astronomers had already detected hints of hot gas around galaxies and along the cosmic web. But hints were not enough. They needed to determine how much matter existed there and whether it could close the enormous gap in the cosmic inventory. To do that, scientists would need a light source on the other side of the universe. And then, without warning, the cosmos began providing thousands of them.

[00:04:00]Fast radio bursts are among the strangest signals ever detected. They appear without warning, release an intense pulse of radio energy, and vanish within milliseconds. Their exact source remains uncertain. Although highly magnetized [music] neutron stars are leading candidates, many of these bursts travel billions of light years [music] before reaching Earth. And that enormous journey transforms them into something far more useful than a cosmic mystery. It turns them into backlights.

[00:04:32]As an FRB crosses space, [music] ionized matter slightly delays its lower radio frequencies. This effect, known as dispersion, records the free electrons encountered along the way. The more matter the burst passes through, the greater the delay. Astronomers can therefore use an FRB like a beam passing [music] through fog. They may not see the fog directly, but they can measure how strongly it changes the signal.

[00:04:58]However, [music] scientists first had to identify each burst's host galaxy and calculate its distance. Only then could they compare how far the signal traveled with how much invisible matter altered it. The new study examined 69 localized fast radio bursts. 39 came from Caltech's DSA110 radio array while the rest were detected by other observatories. The most distant [music] traveled from a galaxy around 9.1 billion lighty years away. Each burst traced a different path through the cosmos. Together, they allowed researchers to separate matter inside galaxies, around their halos, within clusters, and across intergalactic space. For the first time, astronomers were not simply estimating how much ordinary matter existed. They were tracking where it had gone. And the final numbers suggested that scientists had been searching in the wrong place.

[00:06:01]The results revealed where the missing matter had been hiding. Around 76% of the universe's ordinary matter appears to exist in the intergalactic medium, the enormous spaces between galaxies.

[00:06:15]Another 15% surrounds galaxies in vast halos while only a small fraction remains concentrated in stars and cold gas.

[00:06:24]The universe had not lost its matter.

[00:06:28]Most of it was simply hiding beyond [music] the places astronomers could easily observe.

[00:06:33]The space between galaxies may appear empty, but it contains a thin ionized plasma spread across the [music] cosmic web. This enormous network connects galaxies and clusters through filaments stretching millions of light.

[00:06:48]The gas is so diffuse that it produces almost no visible light. Yet across the entire universe, it adds up to an extraordinary amount of material. But the discovery created a new mystery. Why is so much matter outside galaxies?

[00:07:06]Galaxies formed by pulling gas inward to create stars. Scientists therefore expected more of that material to remain inside them or within their surrounding halos. Instead, the results suggest that powerful feedback pushed huge quantities of gas outward.

[00:07:23]Energy from growing stars and activity around super massive black holes can heat surrounding material and drive it far beyond galactic boundaries.

[00:07:33]Over billions of years, these processes may have filled intergalactic space with the matter astronomers were struggling to find. This has major consequences for galaxy evolution.

[00:07:45]Galaxies need gas to create new stars.

[00:07:49]If too much is pushed away, star formation can slow or stop. The location of this hidden gas may therefore reveal how galaxies and their central black holes changed over cosmic time. It could also improve future measurements from missions such as Uklid and the Nancy Grace Roman Space Telescope, which depend on accurate models of how matter is distributed.

[00:08:14]Yet 69 fast radio bursts provide only the beginning. Future observatories could detect thousands of them with every burst tracing another path through the invisible cosmic fog. Together they may eventually produce a detailed map of ordinary matter across the universe.

[00:08:33]The missing matter mystery may finally be closing. But the supposedly empty space between galaxies has now revealed something even more important. a hidden record of how the universe was transformed.

[00:08:51]The universe's missing ordinary matter may finally have been located.

[00:08:57]Most of it appears to exist as thin ionized gas spread across the enormous spaces between galaxies.

[00:09:05]Fast radio bursts provided the evidence by revealing how much invisible material their signals crossed on the journey to Earth.

[00:09:14]Yet, the discovery also raises a deeper question. What pushed so much matter out of galaxies and into intergalactic space?

[00:09:25]What do you think caused this massive redistribution?

[00:09:29]powerful stellar activity, super massive black holes, or maybe a process scientists still do not fully understand.

[00:09:38]Share your theory in the comments. I'm genuinely curious.

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[00:09:53]Thank you for watching and I'll see you in the next