Out there in the cosmic abyss are objects like stars, galaxies and planets. They can coexist peacefully, but sometimes, a star might look so tantalizing, its neighbor will want to eat it.
White dwarfs are very dense stars, comparable in mass to our Sun. These stars are at the end of their lives and can no longer produce any energy on their own to survive. So when gravity pushes a white dwarf next to an energy producing star, it makes its move.
Using its strong gravitational pull, the white dwarf will suck up the outer gas layers of a star. Those gases are essentially star food. In one instance, a white dwarf devoured 90% of a star’s mass, turning it into a brown dwarf. Brown dwarfs are considered failed stars because they can’t shine as brightly. Basically another star sucked the life out of it. This isn’t just something that happens with stars.
Our nearest neighbor, the Andromeda galaxy, is also a space predator. Stars and dwarf galaxies that get too close to Andromeda have reportedly been consumed! And Andromeda is heading our way. The Milky Way and Andromeda galaxy are moving towards each other at about 75 miles per second. It'll take billions of years, but Andromeda will eventually swallow us whole. Creating a super-giant galaxy. Ultimately, the stars and galaxies can’t help it, cosmic cannibalism comes down to gravity.