A close look at a little comet

On this day in 2010, a spacecraft flew past a small comet called Hartley 2 and took close-up pictures as it went by. They showed a long, lumpy ball of ice and dust, with jets of gas streaming off it into space.

Why it mattered

It was only the fifth comet whose solid middle had ever been photographed up close. The pictures helped scientists see where a comet's gas comes from.