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Astronomers Uncover 19 More Galaxies Lacking Dark Matter
· Confirmed
In Short: Astronomers have discovered 19 more galaxies that seem to lack dark matter, bolstering previous controversial findings.
Astronomers have discovered 19 more galaxies that seem to lack dark matter, according to a study published November 26 in Nature Astronomy.
In 2018, researchers led by Pieter van Dokkum of Yale University found a galaxy named NGC 1052-DF2 that appeared to contain very little, if any, 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.
The study suggests that a population of dwarf galaxies could form in a particular way such that much less dark matter is required than for those in the Local Group and those found in simulations.
According to the study, even for such a star-deficient galaxy, it was lightweight: It seemed to contain, at most, 400 times less dark matter than expected, 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 said, 'This invisible, mysterious substance is the most dominant aspect of any galaxy. So finding a galaxy without it is unexpected. It challenges the standard ideas of how we think galaxies work, and it shows that dark matter is real: it has its own separate existence apart from other components of galaxies.'
The findings suggest that astronomers don’t really understand how galaxies form in the first place.
Massey added, 'We are finally homing in on dark matter from above and below — squeezing our knowledge from two directions.'
Astronomers have found that the total mass/energy content of the Universe is split in the proportions of 68% dark energy, 27% dark matter, and 5% 'normal' matter.
What this adds
The new discovery bolsters the controversial recent findings of two other galaxies without dark matter.
The study challenges the standard galaxy formation model and encourages revisiting the nature of dark matter.
The findings suggest that dark matter may interact with other dark matter in ways other than through the force of gravity.
Background
Astronomers have discovered 19 more galaxies that seem to lack dark matter.
What's confirmed
- Astronomers have discovered 19 more galaxies that seem to lack dark matter, according to a study published November 26 in Nature Astronomy.
- In 2018, researchers led by Pieter van Dokkum of Yale University found a galaxy named NGC 1052-DF2 that appeared to contain very little, if any, 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.
- The study suggests that a population of dwarf galaxies could form in a particular way such that much less dark matter is required than for those in the Local Group and those found in simulations.
- According to the study, even for such a star-deficient galaxy, it was lightweight: It seemed to contain, at most, 400 times less dark matter than expected, making DF2 the first dark matter-deficient galaxy ever spotted.
- The findings suggest that astronomers don’t really understand how galaxies form in the first place.
- Astronomers have found that the total mass/energy content of the Universe is split in the proportions of 68% dark energy, 27% dark matter, and 5% 'normal' matter.
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).
- For the first time dark matter may have been observed interacting with other dark matter in a way other than through the force of gravity.
- "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.
- Astronomers have long used these cosmic distortions to track dark matter, the invisible substance thought to make up 85 percent of all matter in the universe.
- 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.