LOS ANGELES, Jan. 25 (Xinhua) -- Scientists from NASA's New Horizons mission released new images of the Kuiper Belt object nicknamed Ultima Thule on Thursday, which was by far the clearest view of the most distant object ever explored.
The images were taken during the historic Jan. 1 flyby of Ultima Thule. New Horizons performed this farthest flyby when it approached Ultima Thule within 2,200 miles (about 3,540 km) of the surface at a velocity of 31,500 miles (about 50,694 km) per hour on the New Year's Day.
Obtained with the wide-angle Multicolor Visible Imaging Camera component of New Horizons' Ralph instrument, this image was taken when Ultima Thule was 6,700 km from the spacecraft, at 12:26 a.m. EST on Jan. 1, just seven minutes before the closest approach.
An image, with an original resolution of 135 meters per pixel, was stored in the spacecraft's data memory and transmitted to Earth on Jan. 18-19, said the team. Scientists then sharpened the image to enhance fine detail.
The oblique lighting of this image reveals new topographic details along the day/night boundary, or terminator, near the top. These details include numerous small pits up to about 0.7 km in diameter. The large circular feature, about 7 km across, on the smaller of the two lobes, also appears to be a deep depression.
Both lobes also show many intriguing light and dark patterns of unknown origin, which may reveal clues about how this body was assembled during the formation of the solar system 4.5 billion years ago, said the team.
"This new image is starting to reveal differences in the geologic character of the two lobes of Ultima Thule, and is presenting us with new mysteries as well," said Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado.
"Over the next month there will be better color and better resolution images that we hope will help unravel the many mysteries of Ultima Thule," he said.
New Horizons is approximately 6.64 billion km from Earth, operating normally and speeding away from the sun and Ultima Thule at more than 50,700 kilometers per hour, said the team.
At that distance, a radio signal reaches Earth six hours and nine minutes after leaving the spacecraft.
