Most scientists believe that the universe is expanding.
How it is expanding, however, remains the subject of debate. The theory states that nothing existed before this collision, and because of it the universe is growing. Physicist Albert Einstein also suggested that the universe is getting bigger, but not because of the creation of anything new. He said the universe is made up from a flexible substance that is stretching outward much like a rubber balloon when filled with air. He claims that planets and stars are getting farther apart because of this stretching motion.