Credit: Credit: NASA, ESA, and D. Ehrenreich (Institut de Planétologie et
d'Astrophysique de Grenoble (IPAG)/CNRS/Université Joseph Fourier)
HUBBLE'S VIEW OF CRATER TYCHO ON THE MOON. This mottled landscape showing the impact crater Tycho is among the most violent-looking places on our Moon. Astronomers didn't aim NASA's Hubble
Space Telescope to study Tycho, however. The image was taken in preparation to observe the transit of Venus across the Sun's face on June 5-6. Hubble cannot look at the Sun directly, so astronomers are planning to point the telescope at the Moon, using it as a mirror to capture reflected sunlight
and isolate the small fraction of the light that passes through Venus's
atmosphere. Imprinted on that small amount of light are the fingerprints of the
planet's atmospheric makeup.
This image, taken with Hubble's Advanced Camera for Surveys, reveals lunar features as small as roughly 560 feet (170 meters) across. The large "bulls-eye"
near the top of the picture is the impact crater, caused by an asteroid strike about
100 million years ago. The bright trails radiating from the crater were formed by material ejected from the impact area during the asteroid collision. Tycho is about 50 miles (80 kilometers) wide and is circled by a rim of material rising almost 3 miles (5 kilometers) above the crater floor. The image measures 430 miles (700
kilometers) across, which is slightly larger than New Mexico.