One of the most interesting results of NASA's policy to make its planetary images widely and freely available is that talented photographers around the world have combined and extended the photos to make clearer or wider views of what it's like to be on another world.
A wonderful example can be found at a site for panoramic (360-degree) images, where photographer Andrew Bodrov has made one of the most exciting space images I have yet seen:
http://www.360cities.net/image/mars-gigapixel-panorama-curiosity-solar-days-136-149#-410.49,13.54,42.5
Bodrov stitched together 407 different images from two different cameras aboard the Curiosity rover on the red planet Mars. You can see the rover itself and the "Yellowknife Bay" neighborhood that it was exploring at the time that it did the first experiment drilling into a Mars rock. The large mountain in the distance is Mt. Sharp, the rover's ultimate destination.
I encourage you to play with the image for a while. There are controls at the upper left to help you move around and your cursor also gives you control of the speed and direction with which you move through this rich image. Enjoy the details of the rover's machinery and the wide range of rock formations around the little robot visitor.
Scientists working with the Cassini space probe orbiting Saturn have recently identified a river more than 200 miles long on the moon Titan. You can see the river valley running into a large sea (to the right) on the radar image. Like the seas on this frigid moon, the river is not filled with liquid water (much too cold for that), but probably liquid methane (swamp gas) and ethane.
Titan has a thick, smoggy atmosphere, so the spacecraft can't just look for features like this using ordinary light. Instead, one of its instruments does the same thing that airport controllers do to keep track of aircraft. It bounces radar beams off the moon's surface and then makes an image using the radar information. On such radar pictures, dark means smooth, light means rough. You can see the smooth dark surface of the river on the accompanying picture, which makes scientists think that the river basin really is full of a flowing liquid with a smooth surface.
This is the first flowing river found on another world besides Earth. Mars has dried-up river beds, but its atmosphere is much too thin to allow liquid rivers or seas today. Titan, on the other hand, has an atmosphere thicker than Earth's, so the pressure is enough to allow liquids to flow.
Earlier radar (and infrared) images of Saturn have identified a number of lakes on Titan, including one as large as Lake Ontario. There are also images that over time, show liquid areas getting smaller and larger, as if they evaporated and then were filled again -- perhaps by rainfall. (Once again, this would be a rain of cold ethane and methane, not water.) Just like the Earth is at "the triple point" of water (boasting temperatures and pressures where water can be solid, liquid and gas), so Titan appears to be at the triple point of methane and ethane and so we can have these substances as vapor, bodies of liquid, and icebergs.
I'm just about to teach my introductory astronomy class on the planets at Foothill College starting Monday and Tuesday, and between the new pictures from Mars and Saturn (to say nothing of Mercury), we'll have lots of astronomy news to keep us occupied. If you can't attend, don't worry. I'll also continue to share the news on this blog as we go along.
At the beginning of November, the Curiosity rover on Mars used a camera on its big arm to take this wonderful panoramic picture of itself and its surroundings. Dozens of individual pictures were stitched together carefully to make this self-portrait.
You can see four little trenches in the front where the arm scooped up some martian dirt for analysis.
Curiously, the way the images are taken and assembled, the arm is NOT visible in the picture. (You could imagine something similar if you held a camera out way in front of you and then took pictures from all sides. You could crop and assemble those pictures in a way so that your arm is always out of sight on the final image.)
In the background, on the upper right, you can see Mount Sharp, the mountain in the center of Gale Crater, which is the rover's ultimate destination. (See my blog post of August 19, 2012 for more on this mountain and its location.)
So far, all the instruments on board Curiosity are working fine, and the mission -- one of the most exciting astronomy events of the past year -- is continuing to send back good information from our red neighbor planet. As expected, we are already seeing clear evidence that there was lots of flowing water on Mars in the distant past.
P.S. If you are interested, you can see an animation of how this complex picture was taken and put together at:
http://www.nasa.gov/multimedia/videogallery/index.html?media_id=156880341
