The galaxy Dragonfly 44 has been a puzzle for the scientific community since its discovery in 2016, as it was found to contain nearly all dark matter. However, a recent study has provided insights into the seemingly “impossible to exist” nature of this galaxy.
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Illustrative Image: Getty
Located 330 million light-years away within the Coma Cluster, this galaxy possesses fewer stars than our Milky Way by a factor of 1,000, rendering it extremely faint.
Four years ago, astronomer Pieter van Dokkum from Yale University studied star clusters within this galaxy and employed standard techniques to determine the amount of dark matter in a given region of space. The findings astonished him.
Dragonfly 44 appeared to be composed of 99.99% dark matter, a revelation that, if confirmed, would prompt a significant reevaluation of our understanding of physical knowledge, astronomical models, and the universe as a whole.
Dark matter cannot be directly observed; instead, its presence is inferred from its effects on the cosmos, much like how we detect the existence of wind through rustling leaves or objects being blown away.
For dark matter, its existence is deduced by observing a phenomenon known as gravitational lensing, wherein light is bent around massive objects due to their powerful gravitational pull. This bending of light helps us determine the mass of an object, such as a galaxy.
Subsequently, astronomers examine this galaxy, calculate the total mass that can be directly detected—stars, planets, nebulae, etc. These masses are then subtracted from the initial measurements derived through gravitational lensing, revealing the amount of dark matter in a specific region.
Using this technique, the scientific community provided the most accurate prediction for the concentration of dark matter in the universe, around 85% (though this figure can vary depending on galaxy type), much lower than the initial 99.99% estimated from Dragonfly 44.
Nonetheless, astronomer Teymoor Saifollahi from the Kapteyn Institute in the Netherlands revisited this data, using stricter criteria and Hubble Space Telescope data like the initial study. He discovered that the amount of dark matter in Dragonfly 44 was significantly lower than previously thought.
“Dragonfly 44 (DF44) has been an anomaly for years, which couldn’t be explained using the galaxy models of the time. However, we have now found that the results of that study were flawed, and DF44 is not anomalous.”
This recalibration has led scientists to redefine our understanding of one of the most elusive and complex aspects that might be among the most crucial in the universe./.