Brenda Karen, age 13, of Vernon, British Columbia,Canada, for her question: 

How many square miles in area is the earth's surface?

Measuring the earth's surface area is no easy job and the most up date estimate may be wrong by a few hundred square miles. Earth scientists estimate the total area to be about 196,940,400 square miles. This is almost but not quite 200 million square miles. This area, of course, includes the surface covered by both land and water. And we live on a watery world. Seen from space, a crew of alien visitors might take it to be a planet of oceans. Only about three tenths of the almost 200 million square miles is not covered with water and almost one tenth of the land is covered by icy glaciers.

 The total land area is estimated to be 57,523,000 square miles, more than five million square miles of which is under the glaciers of Antarctica. The various seas of the world wide ocean cover about 139,417,000 square miles. This is about seven tenths of the total area. Looking down on our vast oceans and immense glaciers, that alien space crew might decide that our wonderful world is an impossible place to support a teeming population of living things