earth

Life on Earth first came out of the oceans, but the water itself may have originated from extraterrestrial space rocks. A new study points to a turbulent period when the solar system's giant planets hurled chunks of icy rubble in Earth's direction.

This goes against the more favored scientific theory that Earth's oceans and atmosphere formed from elements within the planet interior, around 4.5 billion years ago. The Nature study argues that the primordial temperatures never dropped enough to condense both volatile elements and water alike, and that the waters of our blue planet must have arrived during a later period of planet building, about one hundred million years after Earth was formed.

Human activity has widely affected our planet, reshaping surfaces, moving or extinguishing species, and warming the air and water. Now scientists say our reach has been extended even further -- warming oceans may even start to shift the Earth's axis of rotation.

Congress charged NASA with finding 90 percent of nearby space rocks greater than 140 meters (460 ft) by 2020. Now the National Research Council warns that the space agency will fall short of that goal without more funding.

In 2005, we came the closest we ever had before to drilling into the mantle: the layer beneath the Earth's crust. Now, with new drilling technology adapted from the oil and gas industry, scientists might finally be ready to reach that holy grail of depth.

Using Google Earth, his own legwork, and a slew of amateur spies, Curtis Melvin has mapped out all of North Korea's secrets. Called "North Korea Uncovered", the project has pinpointed everything from nuclear facilities to restaurants, from anti-aircraft arsenals to a waterslide.

Google Earth in its current form went live in June 2005. In addition to allowing users to fly to their childhood homes, zoom in on potential vacation spots, and explore under the sea and atop the world's highest peaks, the virtual mapping software has proven instrumental in a number of scientific discoveries -- several in 2009 alone. Here's a look back at some of the highlights.

Any guesses on future Google Earth discoveries? Will Google Earth be an ever-more-important scientific tool in the future? Post in the comments.

There is no denying we humans are obsessed with real estate. We always like to think we've landed ourselves a prime piece of land to settle on, and that outlook extends past your home, vacation home, and country and all the way out to the Earth itself.