The area on the opposite side of Mercury from the large Caloris impact
basin (see PIA10359) is home to uncommonly bumpy and grooved terrain.
Mariner 10 first observed the unusual surface textures at the Caloris
antipodal region, and the Mariner 10 team informally dubbed it the "weird
terrain." (Official geologic maps later adopted the more staid term "hilly
and lineated terrain.") MESSENGER images from the mission's second Mercury
flyby provide a second look at this "weird terrain" under substantially
different lighting conditions. The top image is from Mariner 10, and the
bottom image shows the same surface as seen by MESSENGER. The "weird
terrain" is found mostly to the right of the large, smooth-floored crater
in the images.
MESSENGER Science Team members are using the new views of the "weird
terrain" to compare this region on Mercury with impact basin antipodes on
the Moon. Basin antipodes on the Moon often contain unusual magnetized
crust along with curving bright features called "lunar swirls." The
different lighting condition of the MESSENGER images allowed a new search
for swirl-like features near the Caloris antipode, but no obvious swirls
have been found so far. Two years from now, imaging from orbit will
provide a range of lighting conditions, enabling a more complete search
for any swirl features. Additionally, once in orbit, MESSENGER's
Magnetometer may be able to detect the presence of any magnetized crust in
this region and other basin antipodes.
This new science result and the above images are being presented this week
at the 40th Lunar and Planetary Science Conference. MESSENGER team members
are making a total of 25 presentations at this annual meeting.
Date Acquired: October 6, 2008
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 1 kilometer/pixel (0.6 miles/pixel)
Location: Images cover 327°-347°E, 25°-35°S
These images are from MESSENGER, a NASA Discovery mission to conduct the
first orbital study of the innermost planet, Mercury. For information
regarding the use of images, see the MESSENGER image use policy.