From the thousands of years we are looking at the sky and consider that the whole sky is made up of stars, these stars are everywhere on the universe and they shines in the universe. Let us just come closer to the reality that what actually shines in the sky but we need to know what exactly is hiding from us.
There is mysterious dark matter which holds stars and galaxies together; there is strange repulsive energy which leads to the expansion of the universe. You will be surprised to know that this universe is made up of 98% of dark matter and dark energy; we do not have total proof of their existence.
According to michio kaku “every text book in this planet says that this universe is made up of atoms and sub-atomic particles, these books are wrong” – michio kaku.
The hunting of dark matter starts at 1920, at that time technology is still developed to understand these particles. Edwin Hubble discovered more and more galaxies in the universe and makes our thought beyond the Milky Way galaxy.
At that time that the galaxy clusters are moving faster than their mass, they gave new concept of dark matter and dark energy. According to Einstein theory of relativity the more the mass of the object, the faster the object around it rotates. You can understand it by our sun around which planets are rotating, mercury moving faster than the planet Pluto. This is due to the space time fabric which stretches the space fabric with the weight of the object in the universe.
Most of the scientist found that the galaxies are moving at the constant speed, what drive them to rotate around each other, there must be matter which holds them unless these galaxies will flies off in the space.
Imagine a simple thing, a galaxy have stars that rotates in the galaxy if dark matter wont present they would follow straight path scatters the galaxy. Dark matter particles do not travel with the speed of light, they do not spin, we cannot see it, and they are passing around us.
We cannot discover these kinds of things because they are so small beyond our imagination, all we can doo is that we can show some evidence of their presence.