Last month, NASA’s Cassini spacecraft cruised past Titan at an altitude of 6,200 miles. That’s much higher than other Titan flybys that brought Cassini within 750 miles. But this flyby produced an image that has everyone buzzing.
Thanks to the spacecraft’s visual and infrared mapping spectrometer (VMS), we can look past the moon’s hazy atmosphere and see its surface. According to NASA, we are looking at terrain that is mostly on the Saturn-facing hemisphere of Titan. Remember, Titan is tidally locked, so the same hemisphere always faces Saturn. It’s just like our moon.
Besides the striking surface, you may be wondering why some parts of the image look better than others. NASA calls these areas subframes. Some areas, especially on the left side of the image, were captured when Cassini was at a much lower flyby altitude.
What we are looking at?
That sideways looking ‘H’? It’s made up of two, dune-filled regions. Fensal is to the north. And Aztlan is to the south. A recent study took a look at these dunes. Did you know up to 17% of Titan’s surface is covered with linear dunes?
The linear dunes on Titan are usually 1 to 2 kilometers wide, up to 150 meters high and more than 100 kilometers long. To better understand the dunes on Titan, scientists use a method called comparative planetology. Philippe Paillou of the Université de Bordeaux, France, explains:
“Comparing features on different planets is a very powerful approach. It helps us to understand the geology of regions we can’t directly access. Fieldwork on Titan is still a dream, but by using Earth’s surface as an analogue we can learn huge amounts about Titan’s surface, despite it being over a billion kilometres away.”
Here are radar images of Titan’s dunes.
And radar images of Earth’s dunes.
By comparing the two, scientists can see that there are different types of dunes on Titan. “Being able to distinguish between different types of dune is significant,” says Paillou. “It’s important to know that there’s more than one form of linear dune on Titan, to avoid false interpretations of radar images in the future.”
Last month’s flyby isn’t the last. You can check out Cassini’s schedule for 2016 here. Looks like another close flyby of Titan is set for January 15 at an altitude of 2,372 miles.