The New Blue Marble

By Nancy Atkinson - October 11, 2010 10:59 AM UTC | Planetary Science

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Despite recent news of potential habitable exoplanets and amazing images of Mars and the Saturn system returned from visiting spacecraft, the ol' home planet is still about the most gorgeous-looking planetary body out there. We first saw it as a whole "blue marble" when the Apollo astronauts sent back pictures while circling the Moon, and it has been said that the original "Blue Marble" image taken by the Apollo 17 crew has been one of the most viewed and most influential images ever. But truth be told, that "Blue Marble" really wasn't all that blue (see the original below). However, this new look at the home world shows how prevalent water really is. This composite image is based largely on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite.

It sure is pretty.

According to the NASA Earth Observatory website, Earth's water content is about 1.39 billion cubic kilometers (331 million cubic miles), with the bulk of it, about 96.5%, being in the global oceans. As for the rest, approximately 1.7% is stored in the polar icecaps, glaciers, and permanent snow, and another 1.7% is stored in groundwater, lakes, rivers, streams, and soil. Only a thousandth of 1% of the water on Earth exists as water vapor in the atmosphere.

Here's the original "Blue Marble," the view of the Earth as seen by the Apollo 17 crew traveling toward the moon. This translunar coast photograph extends from the Mediterranean Sea area to the Antarctica south polar ice cap. This is the first time the Apollo trajectory made it possible to photograph the south polar ice cap. Almost the entire coastline of Africa is clearly visible. The Arabian Peninsula can be seen at the northeastern edge of Africa. The large island off the coast of Africa is Madagascar. The Asian mainland is on the horizon toward the northeast.

[caption id="attachment_75517" align="aligncenter" width="580" caption="The original 'Blue Marble' taken by Apollo 17. Credit: NASA"]

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For larger versions of the top image, see

NASA Earth Observatory's website,

and

this link for the Apollo 17 version

, NASA also has

versions of the Blue Marble compiled from various satellites in 2001 and 2002.

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com