August 7th, 2012
03:59 PM ET

A comparison of the Mars rovers

Curiosity had a flawless landing on Mars this week, but it's not the first rover to get to the red planet.

Check out our guide to the Mars rovers to learn more about not just Curiosity, but also its predecessors: Spirit, Opportunity and Sojourner!

Source: JPL, NASA

Post by:
Filed under: Mars
Our big blue marble not very blue
May 8th, 2012
12:03 PM ET

Our big blue marble not very blue

Water covers more than two-thirds of the Earth’s surface, but what would happen if you collected all of it one place?

The illustration above, from the United States Geological Survey, shows the size of a sphere needed to hold all of our planet’s water compared to the size of Earth itself.

The sphere, which is about 860 miles in diameter and 1.39 million cubic kilometers, is about 1/1000 the size of Earth (or 1/20 the size of the moon).

More than 95% of the water sphere comes from world’s oceans, with the remainder made up of water from all other sources including lakes, rivers, and ice caps –- even the water found in plants and animals, according to the USGS.

Post by:
Filed under: On Earth • Science Education


  • Elizabeth Landau
  • Sophia Dengo
    Senior Designer