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Methane is to Titan what water is to the earth. It’s a common component in the atmosphere and, at the temperature of Titan, it can exist in solid, liquid, or gas form. Like water on the earth, it forms clouds in the sky. Like water on the earth, it probably even forms rain. But what we don’t know is whether or not that rain makes it to the surface and pools into ponds or streams or lakes which then evaporate back into the atmosphere to start the cycle over again. In short, we don’t know if Titan has an active methane atmosphere-surface hydrological cycle analogous to the water atmosphere-surface hydrological cycle on the earth.
Until now.
The image above was created by Brown and his colleagues from data returned by Cassini, which has been exploring Saturn and its moons since 2005.
Wayne
Credit: Mike Brown/Caltech
Taken by Cassini on its now five-year tour of Saturn and its moons, this picture shows sunlight glinting from a northern lake on Titan.
How:
The northern hemisphere was shrouded in darkness for nearly 15 years, but the sun began to illuminate the area again as it approached its spring equinox in August 2009. The [Visual and Infrared Mapping Spectrometer] was able to detect the glint as the viewing geometry changed. Titan's hazy atmosphere also scatters and absorbs many wavelengths of light, including most of the visible light spectrum. But the VIMS instrument enabled scientists to look for the glint in infrared wavelengths that were able to penetrate through the moon's atmosphere. This image was created using wavelengths of light in the 5 micron range.
Wayne
Image credit: NASA/JPL/University of Arizona/DLR
Yesterday, however, news emerged that the ground based telescopes of the MEarth Project in Arizona had located a transiting water world orbiting a star very much like ours. Though the second so-called super-Earth, this one is interesting because subsequent observations in South America have demonstrated that this planet has an atmosphere - though perhaps not for long, given the proximity to its host. Paul Gilster at Centauri Dreams provided this other bit of interesting news.
At a distance of 1.3 million miles, the planet orbits its star every 38 hours, with an estimated temperature a little over 200 degrees Celsius. Because GJ 1214b transits the star, astronomers are able to measure its radius, which turns out to be 2.7 times that of Earth. The density derived from this suggests a composition of about three-fourths water and other ices and one-fourth rock.
The atmospheric pressures and resulting lack of light reaching the planet's surface make life improbable, or at least unlike anything we might know, but it's another step along the path toward what could be truly extraordinary find in our lifetimes.
Wayne
The credit for the artist's impression of GJ 1214b goes to ESO/L. Calçada.
On Friday, Kentucky Space held a get together to celebrate the delivery of its first Nanorack and accompanying Cubelabs. As Prof. Jim Lumpp explains, the hardware is scheduled for a Wednesday delivery to the Space Shuttle
Processing Facility, where it will be made ready for a March flight to the International Space Station aboard Discovery.
Check back tomorrow to hear Jim explain a little bit about the Cubelab form factor and why doing microgravity research in these small labs is an important development in orbital science. All Nanorack and Cubelab posts may be found here.
Wayne
