vendredi 29 avril 2016

Pluto: A Global Perspective & New Elevation Map of Pluto’s Sunken ‘Heart’












NASA - Nwe Horizons Mission logo.

April 29, 2016

(Click on the image for enlarge)

Image above: Pluto: A Global Perspective. Image Credits: NASA/JHUAPL/SWRI.

NASA’s New Horizons mission science team has produced this updated panchromatic (black-and-white) global map of Pluto. The map includes all resolved images of Pluto’s surface acquired between July 7-14, 2015, at pixel resolutions ranging from 18 miles (30 kilometers) on the Charon-facing hemisphere (left and right edges of the map) to 770 feet (235 meters) on the hemisphere facing New Horizons during the spacecraft’s closest approach on July 14, 2015 (map center). The non-encounter hemisphere was seen from much greater range and is, therefore, in far less detail.

The latest images woven into the map were sent back to Earth as recently as April 25, and the team will continue to add photos as the spacecraft transmits the rest of its stored Pluto encounter data. All encounter imagery is expected on Earth by early fall. The team is also working on improved color maps.

New Elevation Map of Pluto’s Sunken ‘Heart’. Image Credits: NASA/JHUAPL/SWRI.

This newest shaded relief view of the region surrounding the left side of Pluto’s heart-shaped feature – informally named Sputnik Planum – shows that the vast expanse of the icy surface is on average 2 miles (3 kilometers) lower than the surrounding terrain. Angular blocks of water ice along the western edge of Sputnik Planum can be seen “floating” in the bright deposits of softer, denser solid nitrogen.

Topographic maps of Pluto are produced from digital analysis of New Horizons stereo images acquired during the July 14, 2015 flyby. Such maps are derived from digital stereo-image mapping tools that measure the parallax – or the difference in the apparent relative positions – of individual features on the surface obtained at different times. Parallax displacements of high and low features are then used to directly estimate feature heights.

These topographic maps are works in progress and artifacts are still present in the current version. The map is artificially illuminated from the south, rather than the generally northern solar lighting of landscape during the time of the flyby. One of the many advantages of digital terrain maps is that they can be illuminated from any direction to best bring out different features.  North is up and the total relief in the scene is approximately 4 miles (6 kilometers) from the lowest to the highest features.

For more information about New Horizons, visit: http://www.nasa.gov/mission_pages/newhorizons/main/index.html

Images (mentioned), Text, Credits: NASA/Tricia Talbert.

Best regards, Orbiter.ch

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