Earth

Cradle of Life As We Know It

Earth is the only place we know of in the universe that harbors life. Ours is the largest terrestrial planet in the solar system. Our rocky, volcanic world is coated in a thin veneer of liquid water, living things, and translucent atmosphere, whose complicated interactions make Earth's surface into a place of constant change. We humans have only had fifty years of perspective on Earth as a planet, of seeing it as a "pale blue dot" floating in the black vacuum of space.

With that perspective, we know precious and unique our planet is. We know, too, that we are having measurable effects on the complex interactions of ocean, land, life, water, and air, changing our climate. But predicting the future of our climate is hard. Understanding how Earth's systems work by studying the way they operate on other worlds is a major goal of planetary exploration. Mars, Venus, and Titan all have (or had) active geology, hydrology, and weather -- but, as far as we know, they don't have life. Is Earth really that unique? Are we truly alone in the universe? We won't know unless we keep searching.

News from Earth

A forgotten image of Earth and the Moon

Posted by Emily Lakdawalla on 2013/02/13 07:45 CST | 4 comments

While researching another story, I came across an image I don't remember ever seeing before, of a moonrise from an unexpected source.

The Earth is a Planet: Why We Explore Space

Posted by Bill Dunford on 2013/02/11 10:50 CST

Why spend effort and scarce resources on space exploration when we have so many problems here at home? Turns out, there are some pretty good reasons.

Mount Taranaki, a stratovolcano in New Zealand, from Landsat

Browsing Landsat data is a lot easier than I thought it was

Posted by Emily Lakdawalla on 2013/02/08 05:05 CST | 2 comments

With the Landsat Data Continuity Mission scheduled to launch on Monday, there's been a lot of Tweeting about Landsat, and through one such Tweet I learned about a resource that I hadn't known existed before: the LandsatLook Viewer. This is a graphical interface to more than a decade worth of Landsat data, a tremendous resource for anyone interested in Earth's changing surface, natural or manmade.

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Taken by Voyager 1 on February 14, 1990 from a distance of more than 6 billion kilometers and about 32 degrees above the ecliptic plane. In the image the Earth is a mere point of light, a crescent only 0.12 pixel in size. Our planet was caught in the center of one of the scattered light rays resulting from taking the image so close to the Sun.

A Pale Blue Dot

Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.

Voyager 1's picture of a crescent-shaped Earth and Moon was the first of its kind ever taken by a spacecraft.

Pictures of Earth by Planetary Spacecraft

Many solar system explorers take dramatic photos of Earth as they depart, or fly by; some even have photographed Earth from the vantage point of another planet.

The Earth from GOES-East in visible and infrared

The state of Earth observation, January 2012

As of November 2011, the Earth Observing Handbook counts 109 active missions to study the Earth as a planet, with 112 more approved and planned for the future. Jason Davis provides an overview of key current and upcoming earth-observing missions.