NASA celebrates Earth Day

April’s topic for NASA’s Year of the Solar System (YSS) – Water, Water Everywhere: Celebrating Earth Day!
Planetary scientists once thought Earth was an oasis in a dry solar system, as early missions to our neighbors revealed desert-like conditions on the Moon, Mars, and Mercury. Missions in recent years have overturned this view, returning mounting evidence of ample water from a vast array of locations.
Comets from the remote corners of our solar system are made of water and other ices. Orbiters, landers, and rovers reveal Mars as a watery world in the distant past - a world that today may contain entire underground oceans of frozen water. The Moon, once thought dry-as-a-bone, has a water cycle-with small amounts of water moving across its surface-and voluminous quantities of water ice locked into frozen crater floors at its poles. Rings of ice orbit the gas giants, and several moons of these distant worlds have immense oceans of liquid water beneath their frozen crusts. Even Mercury has ice in the dark craters at its poles, as revealed by the ongoing MESSENGER mission.
Water is critical to life and to future human forays into space. While we now know that Earth is not the only place with water, it is the only oasis that contains life. As we celebrate Earth Day 2011, we should remember to take care of our water resources on our home planet, even as we are discovering water almost everywhere in our solar system!
Join us this month as we celebrate Earth Day (http://www.earthday.org/earth-day-2011)! Share with NASA how you and your family help our planet (http://www.nasa.gov/externalflash/earthday/). And don’t forget to join the world space party and celebrate Yuri’s Night (http://www.yurisnight.net/), with marks the first time a human orbited Earth.
Visit the YSS website (http://solarsystem.nasa.gov/yss/display.cfm?Year=2011&Month=4) to find activities for classroom and informal learning environments, night-sky viewing events and mission milestones, recommended resources, and downloadable materials connected to this month’s theme of Water, Water Everywhere!