[music playing] In the beginning, there was one planet.
At least as far as we knew.
And then there were nine.
And then there were eight.
Our solar system was born as a cloud of gas in the corner of a young Milky Way galaxy.
One molecule stuck to another, and then another, spinning around, and a giant burning sun was born.
The leftover rocks and pebbles swung around, colliding into larger rocks, then larger and larger still, until they had sucked up most of the debris and gas to become the planets we know today.
Now we know that this story has played out around a hundred billion suns.
Some are larger than ours, and some are smaller, some burn hotter and some burn colder, but in the Milky Way, planets are a dime a dozen.
If you were to count our galaxy's hundred billion solar systems one by one, it would take you more than 3,000 years!
