how do you know about the earth?

Question: how do you know about the earth?
- Keywords:
  earth
Asked by jhudson to Carla, Madgie, Nick, Vicky, Werner on 13 Nov 2013.
- Marlene Lorgen answered on 13 Nov 2013:
  
  I wish I know about the earth! I actually know more about what lives on the earth, or rather, in the sea. As scientists we tend to focus on something quite specific in our work so will often know an awful lot about one thing, but very little about others!
- Werner Muller answered on 14 Nov 2013:
  
  I think it was important some time ago that astronauts went to the moon. There is a famous picture from the moon that looks back to earth and the earth appears on the horizon of the moon. I always loved this picture. It shows us how small the earth is and that we are all on this little round blue ball.

Question: how do you know about the earth?