
Scientists believe that the universe is mostly made up of dark matter, a mysterious substance that is different from the ordinary matter people can touch, smell, see, and interact with. Dark matter cannot be directly observed, but it can be studied by examining its effect on...

Scientists believe that the universe is mostly made up of dark matter, a mysterious substance that is different from the ordinary matter people can touch, smell, see, and interact with. Dark matter cannot be directly observed, but it can be studied by examining its effect on...