Also in another study which was taken in 2013 compared how the cosmic x-ray background compared to the cosmic infrared background in the same area in the sky. The earliest stars emitted mainly optical and ultraviolet light. The irregular glow of x-rays in the cosmic x-ray background was similar to the patchiness of the cosmic infrared background quite well (Morrow 2016).The only object that is known to be luminous enough to shine across this wide of an energy range is a black hole. Thus the research team found that primordial black holes must have been popular among early stars making up one out of every five sources that contribute to cosmic infrared background (Morrow 2016). Dark matter still remains as one of the most puzzling issues in the realm of astrophysics. Scientist currently favor theoretical models that explain dark matter as an exotic particle but very little evidence has proven that dark matter exists. This means that there is very little area where these particles can still hide. This is why primordial black holes could be dark matter. There are many ways these early black holes could have formed according to scientists. Black holes could have distorted the distribution of mass in the early days of the universe. This distortion would have added a small fluctuation that would still have been shown when the stars began to form. This is because during the universe’s infant years, the first five hundred million years normal matter was too hot to form stars.
However dark matter was not affected by these temperatures due to it nature with only interacting through gravity. Dark matter first collapsed into mini haloes which enabled the creation of stars (Morrow 2016). It is shown that if black holes play the part of dark matter the process of star creation is accelerated. When cosmic gas fell into the haloes the matter falling towards the black hole creates x-rays which can account for the observed cosmic infrared background and cosmic x-ray background which is seen today.