Why are orbits ellipses?
Planets in the solar system and electrons in orbit travel in elliptical orbits because of the forces of other objects acting on them. If there were no other planets around, the Earth would travel in a circular orbit. Likewise for electrons. Note that new theories say that electrons are in sort of a cloud around the nucleus. Since “c” is the speed of light, the Einstein’s equation shows that mass can be converted to radiant energy. When the atom splits, some of its mass is sent off as high energy particles and gamma rays.