Humans have sent many missions, both manned and robotic, beyond our planet to explore our neighboring celestial bodies. Now and then, these intrepid explorers have glanced home to provide us with sometimes stunning and always thought-provoking images.
Astronaut Harrison Schmitt, Apollo 17 lunar module pilot, is photographed here next to the U.S. flag during NASA's final lunar landing mission in the Apollo series. The photo was taken at the Taurus-Littrow landing site while Schmitt was conducting extravehicular activity (EVA).
This color image of the Earth was taken by the Galileo spacecraft on December 11, 1990, as it departed on its three year flight to Jupiter. Antarctica is visible at the bottom of the image, and dawn is rising over the Pacific Ocean.
This picture of the Earth and Moon in a single frame, the first of its kind ever taken by a spacecraft, was recorded Sept. 18, 1977, by NASAs Voyager 1 at a distance of 7.25 million miles from Earth. Because Earth is many times brighter than the Moon, the Moon was artificially brightened by a factor of three relative to the Earth by computer enhancement so that both bodies would show clearly in the prints.
The European Space Agency's comet chasing mission Rosetta took these infrared and visible images during its Earth fly-by in early March 2005 while on its way to Comet 67P/Churyumov-Gerasimenko. The images gave the Rosetta team a chance to calibrate its instruments on a real space object to make sure everything was in working order.
The iconic image of the Earth rising, the first of its kind taken by an astronaut from lunar orbit, greeted the Apollo 8 astronauts as they rounded the far side of the Moon during their insertion burn. The photo is displayed here in its original orientation, though it is more commonly viewed with the lunar surface at the bottom of the photo.
MESSENGER's Earth flyby on Aug. 2, 2005, not only adjusted the spacecraft's path to Mercury but allowed the spacecraft team to test several of the onboard instruments by taking some shots of its home planet. The camera, designed to characterize minerals that may have formed in Mercury's crust, took this three band composite image on the left using multiple wavelength imaging, giving the continental areas their red color - a result of the high reflectance of vegetation in the near-infrared part of the spectrum.
After traveling more than 727,000 miles in three days, the Mars Reconnaissance Orbiter's cameras were pointed toward Earth on Aug. 15, 2005. The Orbiter's main objective, to obtain daily global images of Martian meteorology, was postponed to help the Mars Color Imager science team obtain a measurement of the instrument's sensitivity and to check that no contamination occurred to the camera during launch.
This image was taken by the Cassini spacecraft's wide-angle camera on Sept. 15, 2006, at a distance of 1.3 million miles from Saturn and about 930 million miles from Earth. The moon Enceladus is also captured on the left, swathed in blue and trailing its plume of water ice particles through Saturn's E ring.
This is the first image ever taken of Earth from the surface of a planet beyond the Moon. It was taken by the Mars Exploration Rover Spirit one hour before sunrise on the 63rd Martian day, or sol, of its mission. Because Earth was too faint to be detected in images taken with the panoramic camera's color filters, the inset image shows a combination of four panoramic images zoomed in on Earth.
Part of the first ever "family portrait" of the solar system taken by Voyager 1 in 1990, this image of Earth was captured from a distance of more than 4 billion miles. Pictured here as a dot only 0.12 pixels in size, the Earth is, as described by Voyager contributor Carl Sagan, "...a lonely speck in the great enveloping cosmic dark. To me, it underscores our responsibility to deal more kindly and compassionately with one another and to preserve and cherish this pale blue dot, the only home we've ever known."