A Moment in Time
A Moment in Time Two worlds, one sun: while humans' lives unfolded on Earth, the Mars Exploration Rover Opportunity paused in its southward trek and captured this photomosaic. Dusty, reddish-brown sand dunes stretch to the horizon in a view taken around 15:00 local Mars time on May 2.

That's the caption submitted along with this photo to the New York Times Lens blog's A Moment in Time project, which solicited people around the world to take a photo near 15:00 UTC on May 2 to document the variety of human experience at a given moment. Humans' presence has extended across the solar system in the form of dozens of autonomous robotic spacecraft. The Mars Exploration Rover Opportunity is now more than six years into a mission originally designed only to last 90 days. It has roved more than 20 kilometers during those six years, and is in the middle of a long trek toward the largest crater it has explored yet. The trek takes it across the wind-whipped dune fields of a region on Mars called Meridiani Planum. The sands are made of grains worn from Mars' basalt volcanic rocks, so the sand is very dark. Here and there, in the troughs separating dunes, lighter-colored bedrock shows through.

The horizon is tilted because the rover was titled, paused in the act of crossing a dune; in reality, Opportunity's horizon is extremely flat. In the foreground, Opportunity's sundial is visible. The sundial, also known as the MarsDial, is both an educational project and an important component of the camera instrument; it serves as a calibration target for the camera. When Opportunity first landed on Mars, the MarsDial's face was different shades of gray, and four different color chips occupied its corners, while its gnomon (the vertical stick) was black. After six years on the Martian surface, the whole thing is covered with a layer of dust that mutes the colors. NASA / JPL-Caltech / Cornell
Data for 'A moment in time'
Data for 'A moment in time' Opportunity took nine shots of Mars to be composed into the color image submitted to the New York Times Lens Blog's "A Moment in Time" project. The imaging began at 11:14 UTC on May 2, 2010 (14:35 local true solar time on sol 2,229 for Opportunity) with the upper left image, captured through the red filter on the rover's left-eye camera. Then the rover rotated the filter wheel to capture the same view through green and blue filters. Next, the rover tilted the camera bar downward to capture the middle view through red, green, and blue filters. Finally, it tilted one last time to capture a view that included the sundial on the rear deck of the rover, again through red, green, and blue filters. Imaging was complete at 11:23 UTC, 14:43 local true solar time. The data were almost immediately transmitted to the Odyssey orbiter, and received by a Deep Space Network antenna on May 2 by 12:25 UTC. A version of this image that preserves the full range of the original data with lossless compression is available here (13 MB).Image: NASA / JPL-Caltech / Cornell