So we come to one of the most entrancing topics of our universe, dark matter. What even is this thing so to speak? And where does it come from?
Quite honestly, dark matter is what its’ name portrays, it is quite dark and there is some energy contained. Essentially the components that make up dark matter are 68% dark energy, 27% dark matter, and 5% normal matter. But what makes up these components? Dark matter is a very sparse subject, there is little clear evidence that explains what dark matter truly is. But what we do know is that it is harmless. Dark matter is essentially the matter that fills up our solar system beyond the area our planets and stars contain. Research has shown that dark matter is mainly subatomic particles that behave in very weak interactions. We also know that dark matter is quite different from the normal particles. So now we have established what dark matter is. But what is it not?
Dark matter is not antimatter meaning there are no gamma rays involved.
What you may be thinking of is how dark matter came to be and why it is there.
We have two possible explanations. The first surrounds MACHO’s or Massive Compact Halo Objects. These come in sizes from small stars to massive black holes. Researchers found that MACHO’s are made up of ordinary matter such as neutrons, electrons, and protons. All of these interact with each other. One may better recognize these as black holes, neutron stars, or even brown dwarfs. There was a project done regarding MACHO’s that actually concluded while there are many brown dwarfs in our Galaxy they did not account for enough that would explain all of dark matter.
Our second explanation is a WIMP(Weakly Interacting Massive Particle). These are containing neutrinos, axions, and neutralinos and are very ordinary in terms of matter. These particles pass through relatively easy through others with barely any effect. It has quite a distinguished mass but it still too weak of a particle to contribute a great amount to dark matter.
With a combination of these two, one may suggest this is what dark matter is made of. However, these two theories combined still would not combine enough mass to be a significant amount of dark matter. The mix is also too weak. Results from the WMAP satellite allow us to see that our universe has only 4% of original matter and that 23% is specifically dark matter. What all else is contained in there remains elusive. Whatever these particles may be, they are quite slow comparably. Neutrinos make up some dark matter however not enough to be considered significant. However the axion and neutralino have properties that correlate to association with dark matter. This thought is still being researched and observed more in depth.https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy