To create the maps, New Horizons researchers, led by Universities Space Research Association (USRA) senior staff scientist, Paul Schenk, at the Lunar and Planetary Institute, registered all the images from the Long Range Reconnaissance Imager (LORRI) and Multispectral Visible Imaging Camera (MVIC) systems together and assembled the mosaics. This labor-intensive effort required detailed alignment of surface features in overlapping images. Digital analysis of stereo images obtained by both cameras were used to create topographic maps for each region; these were then assembled into integrated topographic maps for each body. These new maps of Pluto and Charon were produced painstakingly over a two-year period as data were slowly transmitted to Earth from the New Horizons spacecraft. The quality of geographically and topographically accurate maps improved with each new batch of images that were returned to Earth.
One surprise revealed by the maps: both Pluto and Charon have a lot of elevation. For example: Pluto’s Tenzing Montes range (above) rises up to 6 km above the surrounding plain, and Charon has a topographic amplitude of 19 km (only Iapetus has more). That’s seriously craggy. Keep in mind that these are not large worlds: Pluto’s radius is 1,200 km, Charon’s 600 km. [Michele Bannister]
The Moon and Mars were relatively early additions to Google Earth; that application may have been migrated to the web, but the planets and moons keep coming. Yesterday Google announced the addition of a dozen other worlds in our solar system; the space layer of Google Maps now includes planets Mercury, Venus and Mars; dwarf planets Ceres and Pluto;1 Jupiter’s moons Io, Europa and Ganymede; and Saturn’s moons Dione, Enceladus, Iapetus, Mimas, Rhea and Titan. Large moons Callisto and Triton aren’t included, and Iapetus is projected onto a sphere rather than appearing as the bizarre space walnut it is.
An updated map of Pluto now includes lower-resolution imagery from earlier in New Horizons’ approach. “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.” See coverage from Universe Today and Wired (the latter has a nice loupe feature on the map).
I have studied this area in great detail, and have defined each unit based on its texture and morphology—for example, whether it is smooth, pitted, craggy, hummocky or ridged. How well a unit can be defined depends on the resolution of the images that cover it. All of the terrain in my map has been imaged at a resolution of approximately 1,050 feet (320 meters) per pixel or better, meaning textures are resolved such that I can map units in this area with relative confidence.
By studying how the boundaries between units crosscut one another, I can also determine which units overlie others, and assemble a relative chronology (or timeline) for the different units; this work is aided by crater counts for the different terrains that have been obtained by other team members. I caution that owing to the complexity of the surface of Pluto, the work I’ve shown is in its early stages, and a lot more is still to be done.
New Horizons mission scientists have created a geological map of a portion of Pluto’s terrain. “This map covers a portion of Pluto’s surface that measures 1,290 miles (2,070 kilometers) from top to bottom, and includes the vast nitrogen-ice plain informally named Sputnik Planum and surrounding terrain. As the key in the figure below indicates, the map is overlaid with colors that represent different geological terrains. Each terrain, or unit, is defined by its texture and morphology—smooth, pitted, craggy, hummocky or ridged, for example. How well a unit can be defined depends on the resolution of the images that cover it. All of the terrain in this map has been imaged at a resolution of approximately 1,050 feet (320 meters) per pixel or better, meaning scientists can map units with relative confidence.”
Compare pre-flyby and post-flyby maps of Pluto and you’ll get a sense of just how much our understanding of that dwarf planet’s terrain improved last year. The pre-flyby map was derived from Hubble observations, the post-flyby map from imagery collected from the New Horizons spacecraft (obviously). Image credits: NASA/JHUAPL/SwRI/Marc Buie. [via]
As I predicted, a new global map of Pluto has been released that incorporates the imagery that has been downlinked so far from the New Horizons flyby: with gridlines, without gridlines. If nothing else, the equatorial projection demonstrates how much of Pluto’s surface was not seen during the very brief encounter. From what I understand, imagery downlinks will resume in September and carry on for another year, so this map will almost certainly see many more updates.
The New Horizons spacecraft’s rendezvous with Pluto is next week, folks, but we’re already getting better views of our favourite dwarf planet than we’ve ever had before. NASA has assembled images taken between June 27 and July 3 into the above map, which despite its relatively low resolution shows some intriguing surface features: the so-called “whale” and “donut.” (Of course, low resolution is relative: this is already much better than the Hubble-based maps of Pluto released in 2005 and 2010.)
We’re still two years from the New Horizons flyby of Pluto, but the cartography of the solar system’s most famous dwarf planet—based on Hubble imagery—is already several kinds of problematic, as Emily Lakdawalla explains in a post that also explains how the cartography of other worlds is done. (Key challenges include defining the north and south pole—which one is which?—as well as a prime meridian.)
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