PIA19025: Pourquoi Pas?

Pourquoi Pas?


Why not, indeed?

The cliff-like feature crossing today's image from top to bottom is one of Mercury's famed lobate scarps , and is called Pourquoi-Pas Rupes . Lobate scarps (termed "rupes" in geologic nomenclature, pluralized as "rupēs") on the innermost planet are named for ships of discovery, and this scarp takes its name from Pourquoi-Pas , the fourth ship built for the French polar scientist Jean-Baptiste Charcot. "Pourquoi pas?" is the French term for "why not?" -- a fitting attitude for an explorer, be it of Earth's polar regions or the distant reaches of the Solar System.

Mercury's lobate scarps are thought to be the result of the planet's shrinking as its interior cooled and contracted. Pourquoi-Pas Rupes is one of the largest examples on Mercury, with vertical relief of up to 1.5 km (about 1 mile) in places.

This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.

Date acquired: November 06, 2014
Image Mission Elapsed Time (MET): 57637057
Image ID: 7384633
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 59.9° S
Center Longitude: 195.9° E
Resolution: 89 meters/pixel
Scale: The crater in the center left of the scene is about 22 km (14 mi.) in diameter
Incidence Angle: 61.9°
Emission Angle: 21.7°
Phase Angle: 40.2°
North is to the left in this image.

Background Info:

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.

For information regarding the use of images, see the MESSENGER image use policy .

Cataloging Keywords:

Name Value Additional Values
Target Mercury
Target Type Planet
Instrument Host MESSENGER
Host Type Orbiter
Instrument Mercury Dual Imaging System (MDIS)
Detector Narrow Angle Camera (NAC)
Extra Keywords Crater, Grayscale, Map, Radio
Acquisition Date
Release Date 2015-01-21
Date in Caption 2014-11-06
Image Credit NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Source photojournal.jpl.nasa.gov/catalog/PIA19025
Identifier PIA19025