NASA's Earth Observatory isn't a physical observatory with a state-of-the-art telescope somewhere in orbit, it's actually an office with the mission of collecting all the information the agency gathers on our planet (from orbit and elsewhere) in one place to share with the public. To commemorate the annual college basketball tournament, the Earth Observatory pits a number of its most interesting images of our planet from recent years against each other, bracket-style, and asks the public to pick favorites.
With both tournaments winding down, we gathered our favorite shots that show our changing world in spectacular fashion into this gallery.
In this image we see our home and our neighbor planet Mars, as captured by the Lunar Reconnaissance Orbiter when it took a moment to glance back toward home.
NASA's Operation IceBridge team flies observation missions over the Antarctic and Arctic. During staging flights in Chile, the team got word that the decommissioned aircraft carrier U.S.S. Constellation was being tugged through the Straits of Magellan, taking the long way from Washington state to a US Navy yard in Brownsville, Texas. It's safe to say this is the only constellation NASA ever photographed that served in both the Vietnam and Iraq wars.
Twelve miles off the coast of England we've turned the sea into a power grid in both looks and real terms.
The world's largest offshore wind farm, the London Array, was captured here in 2013 by LandSat 8, just a few weeks after it went operational. The array has the capability to supply power for up to 500,000 homes.
Many borders are invisible in the real world, but others are stark like this look from LandSat 8 of the dividing line between China and Kazakhstan. China's push to farm as much of its land as possible in order to feed its massive population of 1.3 billion people and growing is on full display, even from space.
This shot of China's Piqiang fault is the kind of reminder that Earth is always moving geologically that is best illustrated from a distance. In this particular strike-slip fault it's easy to see where the layers of sedimentary colored rock are offset by about 2 miles, a journey that took place over the course of many millennia.
Iceland is a land of fire and ice in the most literal sense. It's no wonder scenes from the north lands of the Game of Thrones universe are often filmed here.
This LandSat image captured last fall's early eruption of the Holuhraun lava field, which has just recently begun to subside.
Pieces of the Sahara -- lots of them -- have been making the long trip to the new world on the trade wind express.
It sounds like a historical novel, but it's actually a fairly regular phenomenon that delivers literally tons of Saharan sand and dust to the Amazon basin. The process tends to be a good thing for the ecosystem there, but can sometimes wreck air quality for periods.
When a hurricane hit Bermuda in October of 2014, LandSat 8 captured before and after images of the island and surrounding waters. The above split image shows the British territory before Hurricane Gonzalo on the left, and the right half shows the visible plumes of sediment stirred up by the storm, as seen the next day.
In another before-and-after mashup, these LandSat 8 images show how flooding swamped a part of southwestern England known as the Somerset Levels. The left side shows the flooded areas, while the right shows a satellite view under normal conditions.
For decades now, Central Asia's Aral Sea has been shrinking, but in 2014, for the first time, NASA's Terra satellite observed that the large lake's eastern basin on the south side has gone completely dry.
The right half of the image showing the green (shallower) body of water was taken in 2000. That basin is now entirely dry. The 1960 shoreline is also marked.
If you live in the northeastern quadrant of the United States, you may have noticed that it was kind of chilly the past two winters.
While NASA's satellites weren't able to get great shots of the massive piles of snow in Boston and Buffalo, the Aqua satellite captured this false-color image of the Great Lakes in February 2014, showing ice cover (appearing as light blue) on more than 80 percent of the lakes' surfaces.
With winters like this, regulators better hurry up and approve commercial beer drone deliveries for ice fishermen!
This shot taken by astronauts on the International Space Station shows the surprising difference between the different kinds of light on Earth. In this photo of the Tsushima strait that separates Japan and South Korea, the orange-hued lights used in street lamps in Korea can be contrasted with the more greenish light put off by street lights in Japan. The difference is likely due to different types of bulbs.
The light blue lights in the strait itself are likely from fishing boats using bright xenon bulbs to attract Japanese flying squid.
This remarkable image of lightning below a thunderhead cloud was captured by the crew of the International Space Station as it passed over Bolivia in 2011.
Unless, of course, you think it's really evidence of something else.
This view of New York City centered on Manhattan, a photo taken from the ISS, shows millions of hidden humans going about their business. Look closely and...you still won't be able to see them, but there is a way to discern that the city's tallest skyscrapers are found near midtown and the financial district at the end of the island on the right side of the image: notice that both areas register a little darker -- that's due to the longer shadows cast by the buildings.
It's so otherworldly, it almost looks like CGI from a Hollywood sci-fi scene, but this shot is actually a storm over the Sahara that was taken from the International Space Station as it passed over Libya.
Seen from space, the Grand Canyon looks a little less grand. But if you've been there, then to see it reduced to subtle shadows and lines in an image like this gives you a sense of just how grand our entire planet is as a whole.
You can spend more time putting our existence on this rock in perspective with more shots from the latest satellite eyes in the sky, and there's also still time to vote for your favorite Earth Observatory images.