Why isn't Pluto a planet?
The director of the Hayden Planetarium explains.
Latest News: Science Teachers Blast Off
Do you have what it takes to be an astronaut?
How do you build a Mars rover? A NASA scientist explains.
So you think you know about space? Take our quiz!
Need help with a space lesson plan? Take a look at our
(Main Photo: NASA/JPL-Caltech/Cornell)