A NASA Spacecraft Reaches An Exciting First

After a pit stop at the asteroid Vesta, the NASA spacecraft Dawn ended its seven-and-a-half year, 3.1 billion mile journey to the dwarf planet Ceres.

Ceres is the largest object in the stretch between Mars and Jupiter, and scientists say objects like it have a lot to tell us about how our solar system came together--and maybe even how Earth got covered in water.

Kelly Beatty, a senior editor for Sky and Telescope. He tweets @NightSkyGuy.

Sky and Telescope: Dawn Orbiter Reaches Dwarf-Planet Ceres

The Dawn Mission