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Astronomers Find 19 More Galaxies Lacking Dark Matter
· Confirmed
In Short: Astronomers have discovered 19 more galaxies that seem to lack dark matter.
Astronomers have discovered 19 more galaxies that seem to lack dark matter, bolstering the controversial recent discovery of two other galaxies without dark matter.
The latest batch of galaxies missing dark matter was discovered when Guo and her team explored the nature of 324 dwarf galaxies using data from the Arecibo Observatory in Puerto Rico and the Sloan Digital Sky Survey.
According to the study, these galaxies could form in a particular way that requires much less dark matter than those in the Local Group and those found in simulations.
The findings challenge the standard ideas of how galaxies form and suggest that dark matter has its own separate existence apart from other components of galaxies.
In 2018, researchers led by Pieter van Dokkum of Yale University found a bizarre, ghostly galaxy named NGC 1052-DF2 that seemed to contain very little, if any, dark matter.
They discovered that, even for such a star-deficient galaxy, it was lightweight: It seemed to contain, at most, 400 times less dark matter than they would expect, making DF2 the first dark matter–deficient galaxy ever spotted.
Trujillo noted, “Something that caught my attention very early on was the fact that the galaxy [DF2] was not only anomalous for not having dark matter, but also for having an extraordinarily bright population of globular clusters.”
Van Dokkum added, “We thought that every galaxy had dark matter and that dark matter is how a galaxy begins.”
The discovery of these galaxies without dark matter is significant because dark matter is thought to make up 85 percent of all matter in the universe.
Astronomers have long used gravitational lensing to track dark matter, but the new findings suggest that dark matter may interact with other dark matter in ways other than through the force of gravity.
Massey added, “We are finally homing in on dark matter from above and below — squeezing our knowledge from two directions.”
What this adds
The findings challenge the standard models of galaxy formation and the nature of dark matter.
The research suggests that dark matter may not be as integral to galaxy formation as previously thought.
What's confirmed
- Astronomers have discovered 19 more galaxies that seem to lack dark matter, bolstering the controversial recent discovery of two other galaxies without dark matter.
- The latest batch of galaxies missing dark matter was discovered when Guo and her team explored the nature of 324 dwarf galaxies using data from the Arecibo Observatory in Puerto Rico and the Sloan Digital Sky Survey.
- According to the study, these galaxies could form in a particular way that requires much less dark matter than those in the Local Group and those found in simulations.
- The findings challenge the standard ideas of how galaxies form and suggest that dark matter has its own separate existence apart from other components of galaxies.
- In 2018, researchers led by Pieter van Dokkum of Yale University found a bizarre, ghostly galaxy named NGC 1052-DF2 that seemed to contain very little, if any, dark matter.
- They discovered that, even for such a star-deficient galaxy, it was lightweight: It seemed to contain, at most, 400 times less dark matter than they would expect, making DF2 the first dark matter–deficient galaxy ever spotted.
- The discovery of these galaxies without dark matter is significant because dark matter is thought to make up 85 percent of all matter in the universe.
- Astronomers have long used gravitational lensing to track dark matter, but the new findings suggest that dark matter may interact with other dark matter in ways other than through the force of gravity.
What's still developing
- “This result is very hard to explain using the standard galaxy formation model,” said lead author Qi Guo of the Chinese Academy of Science in a press release, “and thus encourages people to revisit the nature of dark matter.” In the late 1970s, astronomers Vera Rubin and Kent Ford of the Carnegie Institution observed our most well-known galactic neighbor: the Andromeda galaxy.
- Close-in Mercury moves much quicker than distant Neptune.
- It meant the Andromeda galaxy must be saturated with huge amounts of invisible matter, stretching far from the galaxy’s center.
- Dating back to the very early stages of cosmic history and caused by normal matter getting “bounced” away from a clustering center, it leaves an imprint that looks a bit like a cosmic bubble: where galaxies are more likely to be found a specific distance away from another rather than slightly closer or farther away.
- In a new study, astronomers used data from the NASA/ESA Hubble Space Telescope to calculate a more accurate distance to an ultra-diffuse galaxy called NGC 1052-DF2 (DF2 for short).
- "Hydrodynamical simulations of the merging cluster El Gordo in a two-state self-interacting dark matter scenario."
- When the gravity of a massive object bends light from a more distant source, it creates distorted, multiple images of galaxies in a phenomenon called gravitational lensing.
- Using data from NASA’s James Webb Space Telescope and Chandra X-ray Observatory, a team of astronomers discovered this low-mass supermassive black hole just 1.5 billion years after the big bang.
- The black hole is pulling in matter at a phenomenal rate — over 40 times the theoretical limit.
- Black holes (center) typically grow by consuming matter via pancake-like accretion disks.
- A few years ago, while using NASA’s James Webb Space Telescope (JWST) to survey some of the Universe’s earliest galaxies, astronomers noticed a peculiar and extremely bright “Little Red Dot” they’ve since concluded is a mashup of a black hole and a star.
- But studying these bright regions, called active galactic nuclei (AGNs), that are sprinkled across the cosmos can teach astronomers about how stars and galaxies form—and possibly shed light on our Milky Way.