Almost every person in the world would say that a galaxy can’t be a galaxy without possessing billions of stars. Over the time, astronomers have discovered either bigger galaxies with hundreds of billions of stars or smaller galaxies with only several millions of stars. However, just recently, a Swiss team of astronomers has discovered six dark galaxies. Also known as starless galaxies, these are nothing else than early stages of galactic formations.
Some theoretical models stipulated that dark galaxies were very common in the early phases of the Universe when the stars were forming with difficulty within the young galaxies after the Big Bang.
Even though dark galaxies are starless, they emit a small amount of light due to the gases and matter compounds that form them. However, the light they emit has very low magnitudes, thus, is very hard for the astronomers to pinpoint these starless galaxies.
Six dark galaxies have been discovered by a Swiss team of astronomers
Astronomers combined the use of a new technology with the traditional method and created a new dark galaxies detection model based on the presence of quasars.
Quasars are among the brightest space objects in the whole Universe and are attracted by the black holes in the center of the galaxies. They emit a very strong UV light which illuminates fluorescent in the hydrogen atoms in the vicinity, in a process called the Lyman-alpha line.
When dark galaxies, which are rich in hydrogen, are in the close vicinity of galaxies that contain quasars, they illuminate and the so-called Lyman-Alpha line will be visible.
Using the Multi Unit Spectroscopic Explorer or MUSE, the scientists examined 6 areas where quasars were present and got the spectral signature of six dark galaxies. However, there is still no clear proof that these space objects are indeed starless galaxies but, astronomers say, they are the closest to this notion than any other known space objects.