20. Particles Responsible For Dark Matter
We have a substantial amount of theory to state that dark matter does exist; it does not interact with normal matter and binds galaxies through the gravitational pull.
What the world is not sure about is that what particles is it made up of? And what properties does it have? It has been discovered that a small number of heavier mass particles were born hot in the universe and are known as neutralino.
Also if a non-particle fluid permeates the Universe then will it gravitate or not? Scientists are doing their homework with the particles and properties of Dark matter, and by all means, with so much work put in, they might as well reach a conclusion soon!