Dark matter is believe to be the solution to the missing mass problem. Dark matter is believed to take up most of the Unvirse. Dark matter was firsted propesed by a man named Frizt Zwicky in 1933. He was observing a cluster of galaxies when he notice he was moving faster around thier centre of gravity point, based on their mass. He worked out that the galaies had to be 400 times in their mass at the rate thatv they were moving, this is called the missing mass problem.

Many other scientist have proposed other solution to tis problem but they all have same characteristics.