Titan’s methane-based hydrologic cycle makes it one of the Solar System’s most geologically diverse bodies. There are lakes of methane, methane rainfall, and even “snow” made of complex organic molecules. But all of that detail is hidden under the moon’s dense, hazy atmosphere.
Now a team of scientists have used data from the Cassini mission to create our first global geological map of Titan.
Ceres’ topography is revealed in full (but false) color in a new map created from elevation data gathered by NASA’s Dawn spacecraft, now nearly five months in orbit around the dwarf planet orbiting the Sun within the main asteroid belt.
With craters 3.7 miles (6 km) deep and mountains rising about the same distance from its surface, Ceres bears a resemblance to some of Saturn’s frozen moons.
“The craters we find on Ceres, in terms of their depth and diameter, are very similar to what we see on Dione and Tethys, two icy satellites of Saturn that are about the same size and density as Ceres,” said Paul Schenk, Dawn science team member and a geologist at the Lunar and Planetary Institute (LPI) in Houston, TX. “The features are pretty consistent with an ice-rich crust.”
Check out a rotation video of Ceres’ topography below:
In addition to elevation mapping Ceres has also had some of its more prominent craters named. No longer just “bright spot crater” and “Spot 1,” these ancient impact scars now have official IAU monikers… from the Roman Occator to the Hawaiian Haulani to the Hopi Kerwan, craters on Ceres are named after agriculture-related gods and goddesses of mythologies from around the world.
Dawn is currently moving closer toward Ceres into its third mapping orbit. By mid-August it will be 900 miles (1448 km) above Ceres’ surface and will proceed with acquiring data from this lower altitude, three times closer than it has been previously.
At 584 miles (940 km) in diameter Ceres is about 40 percent the size of Pluto.
NASA’s Dawn spacecraft is the first to successfully enter orbit around two different mission targets and the first to orbit a dwarf planet. Its first target was the asteroid Vesta, which it orbited from July 2011 to September 2012. Dawn arrived in orbit at Ceres on March 6, 2015 and there it will remain during its primary science phase and beyond; Ceres is now Dawn’s permanent home.
If you could spend a few months — or even a few days — living aboard the ISS, what would you take pictures of? Earth, most likely, with your favorite landforms and your family’s and friends’ hometowns ranking high on the list. After a while, I’m sure plenty of other Earthly features would become photo targets — weather, aurorae, world cities at night, etc. — but ultimately, over the course of your stay in orbit, you would be able to see a trend in the pictures you take, and where you took them.
And over the span of 35 missions across more than 12 years, the graph above shows the trend of all the astronauts’ pictures. Look familiar?
Created by open-source NASA data aficionado Nate Bergey, the image above is a map made up of over a million points (1,129,177, to be exact) each representing the global coordinates of an JSC-archived photograph taken from the ISS.
Clearly the continents are astronauts’ favored photo subjects, with the populous urban areas of North America, Europe, Egypt and the Middle East, as well as the western and southern coasts of South America standing out.
“This makes sense, photos of clouds over an otherwise blank ocean get old after a while,” Nate Bergey wrote on his blog, open.nasa.gov. “I’m sure every astronaut has taken at least one photograph of the town they grew up in.”
Of course, the map doesn’t create an image of the entire globe. This is because the points denote actual over-ground coordinates of the Station (not necessarily what the photos themselves are of) and “the ISS stays between about 50° and -50° latitude as it orbits the Earth,” as noted by Bergey.
A map of the world with the points overlaid onto it, color-coded by mission, shows the difference:
Bergey also notes the proliferation of purple-colored dots… these indicate the hundreds of images taken by NASA astronaut Don Pettit during Expedition 30/31, when he created incredible time-lapse videos of the Earth from the ISS.
With such a unique and lofty perspective of our world, it’s no wonder that astronauts spend so much time snapping photos — I can’t say I’d be able to tear myself away from the window myself! Read more about Nate Bergey’s project and how he created his map on his open.NASA blog here.
Zoomable map of the US and Canada pinpoints everyone with a dot. (Credit: Brandon Martin-Anderson/Census Dotmap)
Now this is something different: an interactive and zoomable map of the United States and Canada, made not from political boundaries or geographic landforms but rather of tiny dots — 341,817, 095 of them, to be exact — each one representing an individual person counted in the 2010 (US) and 2011 (Canada) censuses. There’s no other feature on this map except those dots, each randomly placed within the regional blocks used by the census, yet we still end up with a very recognizable structure.
So if you were listed in either of these censuses, you helped to make this map!
The Census Dotmap is a project by Brandon Martin-Anderson, who wanted an image of human settlement patterns that didn’t use political boundaries. He wrote a script that organized all the census data into points that got drawn into the block-level counts… well, you can see more about how he made it here.
(Just how accurate are population counts? According to the US Census Bureau, the 2010 count was “exemplary”… although renters and certain minority groups are traditionally undercounted.)
Dotmap of the Vancouver, BC area
The bottom line is that this is really interesting to explore… if you live in a somewhat remote area, and you see a dot there, most likely that’s you! (It’s a little harder to determine who’s who in the more populated areas… the dots don’t pinpoint specific street addresses.)
And yes, Alaska and Hawaii are on there too… they just didn’t fit in the screenshot above. In fact all of northern Canada is there too, the dots are just very few and widely spaced out. But it’s not blank.
Check it out… you can even buy a print of the entire map, or a particular region or city. Now that’s leaving your mark on the world!
Part of a stereographic projection of Mercury’s north pole
Talk about northern exposure! This is a section of a much larger image, released today by the MESSENGER team, showing the heavily-cratered north pole of Mercury as seen by the MESSENGER spacecraft’s Mercury Dual Imaging System (MDIS) instrument.
See the full-size image below:
Many MDIS images were averaged together to create a mosaic of Mercury’s polar region, which this stereographic projection is centered on. MESSENGER is at its lowest altitude as it passes over Mercury’s northern hemisphere — about 200 kilometers (124 miles), which is just a little over half the altitude of the ISS.
The largest centrally-peaked crater near the center is Prokofiev, named after a 20th-century Russian composer. Approximately 110 km (68 mi.) in diameter, its permanently-shadowed interior is home to radar-bright deposits that are thought to contain water ice.
Even though Mercury is almost three times closer to the Sun than Earth is and hosts searing daytime temperatures of 425ºC (800ºF), there’s virtually no atmosphere to hold or transmit that heat. Nighttime temperatures can reach as low as -185ºC (-300ºF), and since a day on Mercury is 176 Earth days long it gets very cold for quite a long time!
Also, because Mercury’s axis of rotation isn’t tilted like Earth’s, low elevation areas near the poles receive literally no sunlight. Unless vaporized by a meteorite impact any ice gathered inside these deep craters would remain permanently frozen.
Here’s an orthographic projection of the image above, showing what the scene would look like on Mercury — that is, if it was ever fully lit by the Sun, which it isn’t.
Many of the craters on Mercury’s north pole have recently been named after famous artists, authors and composers, such as Kandinsky, Stieglitz, Goethe, and even one named after J.R.R. Tolkien. You can see an annotated image showing the names of Mercury’s north polar craters here.
On November 29, NASA will host a news conference at 2 p.m. EST to reveal new observations from MESSENGER, the first spacecraft to orbit Mercury. The news conference will be carried live on NASA Television and the agency’s website… you can tune in on NASA TV here.
Image credits: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington