Tuesday, 31 May 2016

Discover the Smithsonian Moon Exhibit On-Line

This February the Smithsonian National Air and Space Museum in Washington D.C. opened an exhibit titled “A New Moon Rises: New Views from the Lunar Reconnaissance Orbiter Camera.” The exhibit, which showcases some of the most spectacular images acquired by the Lunar Reconnaissance Orbiter Camera (LROC) since 2009, is scheduled to run until December 2016. If you live in Washington D.C., or are planning a trip there in the near future, I would encourage you to check out the exhibit, especially since admission to the museum is free.

For the rest of us, the Smithsonian has kindly provided an on-line version for us to experience. Like the physical exhibit, the virtual “A New Moon Rises” exhibit is divided into six themes (Global Views, Exploration Sites, Discoveries, Vistas, Topography and Craters), which can be accessed through the menu bar at the top of the page.

Within the virtual exhibit, you will find some truly spectacular images. Some of my favourites are highlighted below.

Unlike the Earth, the Moon’s axis is not tilted very much. This means that sunlight hits the lunar poles at a very low angle (like at sunrise or sunset on Earth) pretty much all of the time. Some high areas, like mountains and crater rims, will get at least some sunlight most of the year, while low areas, like crater depressions, will get effectively no sunlight, ever. This image of the south pole was created by combining thousands of images taken over a lunar year. It shows what percentage of the year each area is hit by sunlight. The shading is scaled so that areas that get sunlight 100 % of the time show up as white, while those that never get sun are black.  The black areas, known as permanently shadowed regions, get very cold and so are believed to be places where water ice is trapped and preserved from evaporation by the hot sun.
Image Credit: NASA/Goddard Space Flight Center/Arizona State University 

Pairs of stereo images from the LROC Wide Angle Camera, along with altimetry data from the Lunar Orbiter Laser Altimeter, allow topography to be determined for the entire lunar globe.  This image shows the topography of the western limb of the Moon, centred on the Orientale basin.  Orientale is the youngest of the large lunar impact basins and has not been flooded by much lava. As a result, its topography is readily revealed, showing multiple impact basin rings. Here, reds and browns denote high elevation, greens and blues represent medium elevation, and deep blues and purples show areas of very low elevation. 
Image Credit: NASA/Goddard Space Flight Center/Arizona State University 

Giordano Bruno is one of my favourite craters (of course, I covered it in one of my earliest Planetary Geolog posts). This image shows the crater from an oblique angle, which highlights the topography of the rim and floor features of the crater. The sunlight also shows off the interesting landslides on the crater walls.
Image Credit: NASA/Goddard Space Flight Center/Arizona State University 

I hope these few examples will inspire you to explore the virtual “A New Moon Rises” exhibit yourself and find your own favourites.

A New Moon Rises: New Views from the Lunar Reconnaissance Orbiter Camera. Smithsonian National Air and Space Museum On-line Exhibits, Accessed May 31, 2016.