Comet Hartley 2 can be seen in glorious detail in this image from NASA's EPOXI mission. It was taken as the spacecraft flew by around 6:59 a.m. PDT (9:59 a.m. EDT), from a distance of about 700 kilometers (435 miles).
This 3-D image shows the region where NASA's Deep Impact mission sent a probe into the surface of comet Tempel 1 in 2005. This picture was taken six years after the Deep Impact collision. 3D glasses are necessary to view this image.
This image, one of the closest taken of comet Hartley 2 by NASA's EPOXI mission, shows many features across the comet's surface. The length of the comet is equal to the distance between the Capitol building and the Washington Monument in Washington.
This image montage shows comet Hartley 2 as NASA's EPOXI mission approached and flew under the comet. The images progress in time clockwise, starting at the top left.
This frame from an animation series of images of comet C/2012 S1 (ISON) was taken by the Medium-Resolution Imager of NASA's Deep Impact spacecraft over a 36-hour period on Jan. 17 and 18, 2013.
Using NASA's Herschel Space Observatory, astronomers have discovered that comet Hartley 2 possesses a ratio of 'heavy water' to light, or normal, water that matches what's found in Earth's oceans.
This enhanced image, one of the closest taken of comet Harley 2 by NASA's EPOXI mission, shows jets and where they originate from the surface. There are jets outgassing from the sunward side, the night side, and along the terminator.
New measurements from NASA's Herschel Space Observatory have discovered water with the same chemical signature as our oceans in a comet called Hartley 2 (pictured at right). The image at bottom right is an artist's concept of a comet.