{"id":336122,"date":"2025-12-08T02:05:11","date_gmt":"2025-12-08T02:05:11","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/336122\/"},"modified":"2025-12-08T02:05:11","modified_gmt":"2025-12-08T02:05:11","slug":"wheres-the-normal-matter-in-our-universe","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/336122\/","title":{"rendered":"Where\u2019s the normal matter in our universe?"},"content":{"rendered":"

\"NormalMysterious blasts of radio waves from across the universe called fast radio bursts<\/a> help astronomers catalog the whereabouts of normal matter in our universe. Image via ESO\/ M. Kornmesser\/ The Conversation<\/a> (CC BY-SA<\/a>).<\/p>\n

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\u201cNormal\u201d matter is that made from protons, neutrons and electrons. It\u2019s what makes up you and me and the stars.
\nBut most normal matter in the universe isn\u2019t contained within us, or planets, stars or galaxies. So where is it?
\nScientists say the vast majority of the universe\u2019s normal matter lies in the space between galaxies and in galaxy halos.<\/p>\n

By Chris Impey<\/a>, University of Arizona<\/a><\/p>\n

Most normal matter in our universe isn\u2019t found in planets, stars or galaxies<\/p>\n

If you look across space with a telescope, you\u2019ll see countless galaxies<\/a>, most of which host large central black holes<\/a>, billions of stars and their attendant planets. The universe teems with huge, spectacular objects, and it might seem like these massive objects should hold most of the universe\u2019s matter.<\/p>\n

But the Big Bang<\/a> theory predicts that about 5% of the universe\u2019s contents should be atoms made of protons, neutrons and electrons. Most of those atoms cannot be found in stars and galaxies \u2026 a discrepancy that has puzzled astronomers. <\/p>\n

If not in visible stars and galaxies, the most likely hiding place for the matter is in the dark space between galaxies. While space is often referred to as a vacuum, it isn\u2019t completely empty. Individual particles and atoms are dispersed throughout the space between stars and galaxies, forming a dark, filamentary network called the cosmic web<\/a>. <\/p>\n

Throughout my career as an astronomer<\/a>, I\u2019ve studied this cosmic web, and I know how difficult it is to account for the matter spread throughout space.<\/p>\n

In a study published in June 2025, a team of scientists used a unique radio technique to complete the census of normal matter in the universe.<\/p>\n

\"AOrdinary matter such as that in people, planets, stars, and galaxies, comprises only some 5 percent of our universe. Dark matter accounts for roughly a quarter, while dark energy is the largest component of the cosmos. Image via Roen Kelly, after NIST\/ Astronomy.com<\/a>.
\nThe census of normal matter<\/p>\n

The most obvious place to look for normal matter is in the form of stars. Gravity gathers stars together into galaxies<\/a>, and astronomers can count galaxies throughout the observable universe. <\/p>\n

The census<\/a> comes to several hundred billion galaxies, each made of several hundred billion stars. The numbers are uncertain because many stars lurk outside of galaxies<\/a>. That\u2019s an estimated 1023 stars in the universe, or hundreds of times more than the number of sand grains<\/a> on all of Earth\u2019s beaches. There are an estimated 1082 atoms in the universe<\/a>.<\/p>\n

However, this prodigious number falls far short of accounting for all the matter predicted by the Big Bang. Careful accounting<\/a> indicates that stars contain only 0.5% of the matter in the universe. Ten times more atoms are presumably floating freely in space. Just 0.03% of the matter is elements other than hydrogen and helium<\/a>, including carbon and all the building blocks of life.<\/p>\n

Looking between galaxies<\/p>\n

The intergalactic medium<\/a> \u2013 the space between galaxies \u2013 is near-total vacuum, with a density of one atom per cubic meter, or one atom every 35 cubic feet. That\u2019s less than a billionth of a billionth of the density of air on Earth. Even at this very low density, this diffuse medium<\/a> adds up to a lot of matter, given the enormous, 92-billion-light-year diameter of the universe<\/a>. <\/p>\n

The intergalactic medium is very hot<\/a>, with a temperature of millions of degrees. That makes it difficult to observe except with X-ray telescopes<\/a>, since very hot gas radiates out through the universe at very short X-ray wavelengths<\/a>. X-ray telescopes have limited sensitivity because they are smaller than most optical telescopes. <\/p>\n

A new tool to search for normal matter in our universe<\/p>\n

Astronomers recently used a new tool to solve this missing matter problem. Fast radio bursts<\/a> are intense blasts of radio waves that can put out as much energy in a millisecond as the sun puts out in three days. First discovered in 2007, scientists found that the bursts are caused by compact stellar remnants in distant galaxies. Their energy peters out as the bursts travel through space, and by the time that energy reaches the Earth, it is a thousand times weaker than a mobile phone signal would be if emitted on the moon, then detected on Earth. <\/p>\n

Research from early 2025 suggests the source of the bursts<\/a> is the highly magnetic region around an ultra-compact neutron star. Neutron stars<\/a> are incredibly dense remnants of massive stars that have collapsed under their own gravity after a supernova explosion. The particular type of neutron star that emits radio bursts is called a magnetar<\/a>, with a magnetic field a thousand trillion times stronger than the Earth\u2019s.<\/p>\n

\"An<\/a>A magnetar<\/a> is a rare type of neutron star with an extremely strong magnetic field. Image via ESO<\/a>\/ L. Cal\u00e7ada (CC BY-ND<\/a>).<\/p>\n

Even though astronomers don\u2019t fully understand fast radio bursts, they can use them to probe<\/a> the spaces between galaxies. As the bursts travel through space, interactions with electrons in the hot intergalactic gas preferentially slow down longer wavelengths. The radio signal is spread out, analogous to the way a prism turns sunlight into a rainbow. Astronomers use the amount of spreading to calculate how much gas the burst has passed through on its way to Earth.<\/p>\n

Puzzle solved<\/p>\n

In the new study<\/a>, published in June 2025, a team of astronomers from Caltech and the Harvard Center for Astrophysics studied 69 fast radio bursts using an array of 110 radio telescopes in California. The team found that 76% of the universe\u2019s normal matter<\/a> lies in the space between galaxies, with another 15% in galactic halos<\/a> \u2013 the area surrounding the visible stars in a galaxy \u2013 and the remaining 9% in stars and cold gas within galaxies.<\/p>\n

The complete accounting of normal matter in the universe provides a strong affirmation of the Big Bang theory. The theory predicts the abundance of normal matter<\/a> formed in the first few minutes of the universe, so by recovering the predicted 5%, the theory passes a critical test.<\/p>\n

Several thousand fast radio bursts have already been observed, and an upcoming array of radio telescopes<\/a> will likely increase the discovery rate to 10,000 per year. Such a large sample will let fast radio bursts become powerful tools for cosmology<\/a>. Cosmology<\/a> is the study of the size, shape and evolution of the universe. Radio bursts could go beyond counting atoms to mapping the three-dimensional structure<\/a> of the cosmic web.<\/p>\n

Dark energy and dark matter in the universe<\/p>\n

Scientists may now have the complete picture of where normal matter is distributed, but most of the universe is still made up of stuff they don\u2019t fully understand.<\/p>\n

The most abundant ingredients in the universe are dark matter<\/a> and dark energy<\/a>, both of which are poorly understood. Dark energy is causing the accelerating expansion of the universe<\/a>, and dark matter is the invisible glue that holds galaxies and the universe together. <\/p>\n

Dark matter is probably a previously unstudied type of fundamental particle<\/a> that is not part of the standard model<\/a> of particle physics. Physicists haven\u2019t been able to detect this novel particle yet. But we know it exists because, according to general relativity<\/a>, mass bends light<\/a>. And far more gravitational lensing<\/a> is seen than can be explained by visible matter. With gravitational lensing, a cluster of galaxies bends and magnifies light in a way that\u2019s analogous to an optical lens<\/a>. Dark matter outweighs conventional matter by more than a factor of five. <\/p>\n

One mystery may be solved, but a larger mystery remains. While dark matter is still enigmatic, we now know a lot about the normal atoms making up us as humans, and the world around us.\"The<\/p>\n

Chris Impey<\/a>, University Distinguished Professor of Astronomy, University of Arizona<\/a><\/p>\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n

Bottom line: The planets and stars you can see in the night sky are made of normal matter. Yet only 9% of the universe\u2019s normal matter is in objects such as these. Where is the rest of it?<\/p>\n","protected":false},"excerpt":{"rendered":"Mysterious blasts of radio waves from across the universe called fast radio bursts help astronomers catalog the whereabouts…\n","protected":false},"author":2,"featured_media":336123,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49],"tags":[199,79,193],"class_list":{"0":"post-336122","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-physics","9":"tag-science","10":"tag-space"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/336122","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=336122"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/336122\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/336123"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=336122"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=336122"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=336122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}