This is kind of cool. Astronomers using the Gemini and Keck observatories on Mauna Kea, Hawai’i have spotted clouds in the atmosphere of Saturn’s largest moon, Titan. This isn’t the first time clouds have been found; astronomers have also seen them at Titan’s south pole and reasoned that they were caused by solar heating of the polar region.
However, these new clouds were spotted in early 2004 at the mid-latitudes of the moon, and are not likely to be caused by solar heating. So, what could be driving the formation of cloudy features in Titan’s nitrogen atmosphere? One explanation could be something happening on the surface that affects the atmosphere, like methane geysers or volcanoes that spout icy slush instead of lava (called cryovolcanism). It’s also possible that these features are being driven by some sort of changes in the global winds that circulate in the upper parts of Titan’s atmospheric blanket. The good news is that astronomers have a reporter “on site” in the form of the Cassini-Huygens mission. It’s likely the spacecraft has also recorded observations of these clouds and we may hear more about them from Cassini mission scientists. Incidentally, those researchers are gearing up for a big event on Christmas Day, 2004: the launch of the Huygens probe toward Titan, and an eventual surface landing sometime in the middle of January. Keep an eye out for more Titan news in the coming days and weeks!
The past few months I’ve been working with the Gemini Observatory, doing a series of interesting and absorbing projects for their outreach team. These range from science reports and newsletters to press release edits and consultations. A couple of weeks ago they sent me this great image of members of Stephan’s Quintet, a troupe of five galaxies that lies about 300 million light-years away. What we see here tells an interesting tale of galactic intrigue.
Courtesy Gemini Observatory
Some members of the group are interacting with each other, tearing huge swaths of gas and stars away from each other in a sort of cosmic dance. One thing that really stands out in this image is a collection of brilliant red clumps in the spiral galaxy NGC 7320 (just above the center of the image). These are star-forming regions as seen with the help of a special filter.
This galaxy may or may not be part of the Quintet—its relation to the other galaxies in the cluster is the subject of some controversy. Most astronomers now think that NGC 7320 is quite some distance away from the others. Spectroscopic data show its apparent velocity away from us at around 800 kilometers per second. The rest of the group is moving away from us (through the expansion of the universe) at over 6,000 kilometers per second. This puts the the other galaxies in the cluster almost 8 times farther away from us than the brilliantly-lit spiral.
The interacting members of Stephan’s Quintet will continue their dance for millions of years, but eventually they will combine into a different, smaller set of objects than we see today.
