Water Above, Water Below, Water Within: The Many Roles of Water in Making Planets Habitable

[@rtropson]

Very informative, Loved this lecture! However, I question the illustration showing the sphere radius of water for the earth compared to other moons, etc. In particular, the radius of water on the surface of the earth is shown as 225 miles which equates to a volume of 47.7 million cubic miles. However NOAA and other sites show approximately 321 Million cubic miles as an estimate (plus or minus a few percent). Using that data, the radius of water on the surface of the earth would equate to 425 miles - nearly twice the radius. Could you explain the discrepancy?

[@rhoddryice5412]

Ads every six minutes is a wee bit excessive I think.

[@Draliseth]

Yeeeesh. That's.. I'm sorry.