billions and billions

In these galaxies, stars and their solar systems whirl around at high speed, slowly coming together toward the galaxy’s central Black Hole.

The number of stars in your average galaxy is about 100 billion.

The galaxy where we live is called the Milky Way. It contains 200–400 billion stars and may contain at least as many planets, which whirl around those stars.

Scientists tell us that this vast galaxy is moving through space at a velocity of 343 to 391 km per second, depending on the relative frame of reference.

It is estimated to be about 13.7 billion years old, nearly as old as the Universe.

NEXT