Saturn’s shrouded moon Titan is coming in for an in-depth study by the Cassini-Huygens mission currently exploring the Saturn system. In order to image what lies beneath this tiny moon’s gigantic atmosphere, astronomers image it in different wavelengths of light. Using ultraviolet- and infrared-sensitive instruments to gather data about Titan’s surface, they were able to piece together this “peek beneath the veil.” Red and green colors represent infrared wavelengths and show areas where methane in Titan’s atmosphere absorbs light. Blue represents ultraviolet wavelengths and shows the high atmosphere and detached hazes.
Titan’s atmosphere extends hundreds of kilometers above the surface. What lies beneath those clouds is the target of the Huygens probe, set to descend to Titan’s surface on December 25, 2004. From this radar image, what we can see so far appears to be smooth, made of radar-absorbing materials, or possibly a region that slopes away from the direction of illumination.
A synthetic aperture radar image of Titan's surface. Courtesy Cassini-Huygens Mission
The striking bright feature that stretches from upper left to lower right across this image, with connected ‘arms’ to the East could be some sort of flowing material, possibly where water-rich liquid has welled up from Titan’s warm interior. Scientists are hoping that the probe will survive long enough to give an idea about exactly what’s happening on the surface of this shrouded world. Keep your eyes turned to Titan on December 25th!
Near infrared images of Uranus before and after the AO system on Keck was used (Image credit: Heidi B. Hammel and Imke de Pater)
What’s the latest at Uranus? According to Professor Imke de Pater (University of California, Berkeley) and Heidi Hammel (Space Science Institute), the 7th planet out from the Sun is not the boring and unchanging planet everybody thinks it is. The weather’s changing as the southern hemisphere summer at Uranus comes to a close. There are more clouds in the upper atmosphere than scientists saw when Voyager first approached the planet back in 1986. This is due to high-altitude cloud activity perpetrated by strong convection currents in the atmosphere. If you look at the planet with infrared-enabled instruments, those clouds really stand out. And, as an added bonus, there’s a newly discovered dim ring to be checked out. This new one, called 1986U2R, is—like the other rings in the system—only only a single layer of boulder-sized particles thick. That’s downright diaphanous by ring standards!
These discoveries weren’t made with a flyby spacecraft. Instead, the Uranus observation teams have been using the Keck telescope out on Mauna Kea (Hawaii), and the careful application of adaptive optics (a method to “erase” the effects of atmospheric aberration from ground-based observations).
What’s next for Uranus as the seasons change? Maybe more clouds will bubble their way up from the depths of the planet’s atmosphere. Nobody’s quite sure, since this is the first time the planet’s seasons have changed since high-resolution telescopes like the Keck and others have been in use.
