Scientists have discovered a faraway galaxy without dark matter, which may ironically prove the existence of dark matter and its importance to the universe.
There have been several ideas that have floated around regarding the true nature of dark matter, and discoveries like this will only push astronomers to unlocking its secrets.
What Is Dark Matter?
Dark matter is a mysterious material that is believed to be present throughout the universe. Nobody knows exactly what it is, but scientists believe that it is out there because in can be observed when galaxies and stars move.
Dark matter is believed to exist because of its gravitational effects on visible matter in the cosmos. It is also thought to be more abundant than regular matter, with dark matter making up 27 percent of the mass and energy of the universe compared to just 5 percent for the matter that we can see.
Galaxy With No Dark Matter Discovered
Every galaxy that has been spotted contained a dark matter signature. However, a newly discovered galaxy named NGC1052-DF2 is believed to have practically no dark matter at all, with 400 times less of the material than expected based on its volume and size.
According to Yale University researcher Pieter van Dokkum, who is also the lead author of the study published in Nature detailing the discovery, NGC1052-DF2 challenges the standard idea of how galaxies are formed.
"Dark matter is apparently not a requirement for forming a galaxy," said Van Dokkum. The discovery also raises the possibility that there are even more galaxies out there without dark matter and that there is a wide range on how much dark matter galaxies contain.
Ironically, the absence of dark matter in the newly discovered galaxy may provide further proof of its existence. If dark matter only served to explain the effect of the gravity from regular matter, it should still be visible in NGC1052-DF2.
"So it only makes sense if dark matter is a real substance, that can be present or not, separately from the regular matter," said North Carolina State University astrophysicist Katherine Mack.
Proving The Existence Of Dark Matter
About a year ago, University of Waterloo researchers captured a composite image that strongly supports the existence of dark matter. The image also served as a confirmation that galaxies are interconnected through a cosmic web of dark matter.
Almost a year later, a team from the Haystack Observatory at MIT reported that they spotted traces of the earliest light in the universe, which are believed to have come from the first stars, which formed about 180 million years after the Big Bang. The discovery provided more clues into how dark matter works.
Unfortunately, dark matter research is facing a hurdle, as the Trump administration's NASA budget proposal for fiscal year 2019 places the funding of the Wide-Field Infrared Survey Telescope in question. The WFIRST, planned to launch in the mid-2020s, was designed to study dark matter.