Space Maps: Ceres, Mars, Exoplanets

Mars: Ares Vallis

Geologic Maps of Vesta

Geologic map of Vesta
NASA/JPL-Caltech/ASU

Geologic maps of Vesta, the asteroid visited by the Dawn spacecraft between July 2011 and September 2012, have been produced for a special issue of the planetary science journal Icarus. Above, a global geologic map of Vesta, compiled from 15 individual quad maps and using a Mollweide projection (Vesta itself is decidedly non-spheroid, but still).

Previously: Atlas of Vesta.

Moon and Comet Maps

OSIRIS map of Comet 67P/Churyumov-GerasimenkoTopography of Earth's moon

Maps of planets, moons and other objects in our solar system always get me excited, though truth be told they were among the less popular posts on my old Map Room blog. Here are a couple of rather colourful recent examples:

Image credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA (above left); NASA/Colorado School of Mines/MIT/GSFC/Scientific Visualization Studio (above right).

Geologic Map of Mars

Geologic Map of Mars

As I said during the Q&A part of my fantasy maps presentation at Readercon (see previous entry), maps of other worlds in the solar system are usually images from space probes that have been set to a map projection. The key word is usually. On Monday the U.S. Geological Survey released a geologic map of Mars that “brings together observations and scientific findings from four orbiting spacecraft that have been acquiring data for more than 16 years.” Via io9 and Wired.

Ganymede and Mercury

Geologic map of Ganymede

The USGS has published a geologic map of Ganymede, Jupiter’s largest moon and the largest moon in the Solar System, based on imagery from the Voyager 1, Voyager 2 and Galileo probes. Via Centauri Dreams, Sky and Telescope.

Meanwhile, Sky and Telescope has produced a Mercury globe based on MESSENGER imagery. They already produce both visual and topographic globes of the Moon and Mars, as well as a globe of Venus coloured for elevation. (I’m crossing my fingers for globes of the outer moons, myself.)

I’m big on maps and globes of the rest of the Solar System. Recent entries: Maps of Mercury; Atlas of Vesta; A Topographic Map of Titan.

More Map Books

Book cover: Mr. Selden's Map of ChinaBook cover: Golden Age of Maritime MapsBook cover: Maps of ParadiseBook cover: International Atlas of Mars Exploration

Here are some map books that I recently found out about:

Maps of Mercury

H-12 Michaelangelo

The USGS has released quad maps of the planet Mercury as a set of PDF files: “The 1:5 million-scale series of Mercury maps divides Mercury into 15 quadrangles, H-1 through H-15 (five Mercator, eight Lambert Conformal, and two Polar Stereographic quadrangles). The base mosaic was produced with orbital images by the MESSENGER Team and released by NASA’s Planetary Data System on March 8, 2013. This new global mosaic includes 100% coverage of Mercury’s surface.”

Pluto’s Problematic Cartography

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.)

A Topographic Map of Titan

Global topographic map of Titan (NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann)
NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann

The Cassini team has released a global topographic map of Saturn’s moon Titan. What makes this map interesting is the fact that, due to its thick atmosphere, Titan can only be mapped by radar during Cassini’s close flybys. As a result, only half of its surface has been imaged, and only 11 percent has topography data. For this map, the remainder was, well, extrapolated:

Lorenz’s team used a mathematical process called splining—effectively using smooth, curved surfaces to “join” the areas between grids of existing data. “You can take a spot where there is no data, look how close it is to the nearest data, and use various approaches of averaging and estimating to calculate your best guess,” he said. “If you pick a point, and all the nearby points are high altitude, you’d need a special reason for thinking that point would be lower. We’re mathematically papering over the gaps in our coverage.”

Topo maps of parts of Titan have been released before, but not for the entire moon. See previous posts on The Map Room: Titan in Stereo; Topography of Titan.

Lunar Gravity Map

Free-Air Gravity Map of the Moon
NASA has released a free-air gravity map of the Moon: “If the Moon were a perfectly smooth sphere of uniform density, the gravity map would be a single, featureless color, indicating that the force of gravity at a given elevation was the same everywhere. But like other rocky bodies in the solar system, including Earth, the Moon has both a bumpy surface and a lumpy interior. … The free-air gravity map shows deviations from the mean, the gravity that a cueball Moon would have.” Gravity data comes from the GRAIL mission, with the digital elevation model provided by the Lunar Reconnaissance Orbiter laser altimeter. Image credit: NASA’s Goddard Goddard Space Flight Center Scientific Visualization Studio.

New Moon Globe Released

Moon Globe Calling it “the first entirely new globe of the lunar surface in more than 40 years,” Sky and Telescope has announced a new Moon globe based on Lunar Reconnaissance Orbiter imagery. Replogle’s Moon globe has been the standard for decades, but it’s based on 1960s-era charts and, as I said in my review three years ago, doesn’t have a lot of contrast and doesn’t look much like the Moon. Mind you, the new globe costs almost twice as much.

Geologic Map of Io

Geologic map of Io (small)

In my review of Paul Schenk’s Atlas of the Galilean Satellites I noted that the maps of Jupiter’s four largest moons were actually spacecraft imagery placed on a map projection; there were no non-photographic maps. In that context, the geologic map of Io, just out from the U.S. Geological Survey, is both novel and pertinent. The maps are based on Voyager– and Galileo-derived photomosaics of Io’s surface released in 2006, but they’re maps. ASU news release, Universe Today.

Atlas of the Galilean Satellites

Paul Schenk’s Atlas of the Galilean Satellites (Cambridge University Press, 2010) collects all the imagery gathered by the Voyager and Galileo missions of the four major moons of Jupiter (Callisto, Ganymede, Europa and Io, all discovered by Galileo in 1610) and assembles them into global, quadrangle and area maps. But this heavy, 400-page tome begins with a confession. “This Atlas is not what it should be.” The failure of the high-gain antenna on the Galileo spacecraft meant that far less data could be transmitted back to Earth during its nearly eight-year mission than had been planned. Large tracts of the moons are mapped in low resolution; the fuzzy images yield little detail. But until another mission is sent—the Juno probe now en route to Jupiter will not be studying the moons—this is all there will be for the foreseeable future. For decades, in fact.

The Atlas of the Galilean Satellites therefore represents a treasure trove of all available imagery of these four moons. The further out you go, the less imagery there is: outermost Callisto gets 49 pages of plates, innermost Io, with all its interesting volcanoes, gets 89. Despite the inevitable blurry patches, there are some extraordinarily high-detail images here. One problem, though, is that the global maps are unlabelled; I found it difficult to place features that were labelled on the quadrangle, regional and detail maps in their global context. Also worth noting is that—and I suspect this is the norm for extraterrestrial mapping—these are not maps per se, but spacecraft imagery labelled and put on a map projection.

One issue that has been noted elsewhere—for example, in Emily Lakdawalla’s review last November—is that several copies of this book have been defective, with pages falling out. My own copy is fine, but seems a bit fragile. (UPDATE: Laying it open flat once was enough for several pages to come loose.) The signatures appear to be glued rather than sewn—a textbook example of the badly built British book—which is inexplicable given the size of the book and weight of the glossy paper, to say nothing of its cost. Because, at $165 (£95) list, this book is extremely expensive; ebook versions are just as exorbitant. Cheaper copies can be found elsewhere with a little digging: I got mine via AbeBooks for less than $30, shipping included. Honestly, given the risk of the book falling apart on you, that’s the way to go.

This atlas isn’t really aimed at beginners or people with a casual interest in the solar system. The price reflects that, as does its rather technical nature and organization. Those with a serious jones for the solar system will not be deterred by these or any other reservations.

Previously: Blogs and a Book About Maps of the Solar System’s Moons.

Amazon | iBooks

More Moon Maps

Chinese scientists have released a high-resolution map of the Moon based on images from the Chang’e 2 spacecraft; the maps are at a resolution of seven metres (MoonViews, Universe Today). Phil Stooke compares the Chang’e 2 images with those from the Lunar Reconnaissance Orbiter Camera (LROC). Meanwhile, and speaking of the LROC, Jeffrey Ambroziak is making 3D anaglyph maps based on LROC data; he’s launched a Kickstarter campaign to create a 3D digital map of the entire Moon.