If you've ever had to dig a hole and then fill it back in, you may have noticed a mysterious thing: there was always a little dirt left over. Why?
It was a great moment in the history of NASA, especially since people had been working so long at trying to get a probe to Mars
You may not realize it, but you're full of emptiness. Learn more on this Moment of Science.
What does air actually consist of? Find out on this Moment of Science.