Moar Science from Cassini


As the Cassini spacecraft was running out of fuel for the thrusters used to maintain control of its attitude so that it could point it instruments at the desired targets and its antenna toward Earth so send back data, it was placed in a series of Grand Finale orbits that took it between Saturn’s rings and the planet’s upper atmosphere. Eventually, an orbit was low enough that the spacecraft burned up in the upper atmosphere. It will take years to go through all the data, but papers are beginning to be published with findings from the Grand Finale. Interesting findings include an electric current that flows between the rings and the upper atmosphere and organic compounds falling as “rain” from the rings. There’s more interesting stuff here. Go take a look.

Image Credit: NASA

The Dust Storms of Titan


Analysis of data taken by the Cassini spacecraft appears to show giant dust storms on Saturn’s moon Titan. Titian is the second largest moon in the Solar System (Jupiter’s moon Ganymede is slightly bigger.); it’s even lager than the planets Mercury and Pluto (Pluto is still a planet in the Hogewash! universe.). Titan is the only other body in the Solar System beside Earth that has stable surface liquid, hydrocarbons rather than water. If the dust storms are really occurring, it would join Earth and Mars as the only known bodies in the Solar System with dust storms.

The animation above is based on images captured by Cassini mission during several Titan flybys in 2009 and 2010. The bright spots that have been interpreted as evidence of the dust storms.

There’s more information about this at the NASA website.

Image Credit: NASA

Not a Solar Eclipse


titanbusy_cassini_960No, it’s not a solar eclipse. It’s a picture of the rings and a couple of the moons of Saturn. The large object near the center is Titan, Saturn’s largest moon and one of the most interesting objects in the entire Solar System. The central dark spot is the body of the moon. The bright halo is atmospheric haze above Titan. The gases of the atmosphere scatter sunlight. Saturn’s rings are shown nearly edge on. Enceladus, a small moon, is at about 4 or 5 o’clock at the edge of Titan.

This image was taken with the Cassini spacecraft’s camera pointing almost directly at the Sun, so the surfaces of Titan and Enceladus appear in silhouette, and the rings of Saturn look like a photographic negative.

Image Credit: NASA

You Can’t See This From Here


Crescent SaturnThis is a view of Saturn partially lit in crescent phase, a view that can only be seen when the object is between the observer and the Sun. From the Earth, we can only see Mercury and Venus in varying crescent phases and Mars and the other outer planets fully lit. Because the Moon can be either between the Earth and the Sun or farther away, we see it go through all the phases from New to Full to New again.

This picture of Saturn was made by the Cassini spacecraft.

Image Credit: NASA

Translucent Rings


Saturn’s rings are mostly water ice in chunks that range in size from smaller than a grain of sand to mountains. The ring system extends 282,000 km from the planet, but it’s only about 10 m thick in most places. Looking from some angles, it’s possible to see through the rings—as in this that looks from south to north. The Cassini spacecraft took the images stitched together in this natural-color mosaic in April, 2007, when it was about 725,000 kim from Saturn.

Image Credit: NASA

A Reflection from Titan


titan_lake_flashThis image shows a flash of sunlight reflected off a lake on Titan, Saturn’s largest moon. Its northern hemisphere is shrouded in darkness for nearly 15 years, but the sun begins to illuminate the area again as it approaches its spring equinox. The Cassini spacecraft was able to detect the glint at the beginning of Titan’s spring in 2009. The moon’s hazy atmosphere scatters and absorbs many wavelengths of light, including most of the visible spectrum. But an onboard instrument was able to detect the glint in infrared wavelengths that can penetrate through Titan’s atmosphere. This image was created using wavelengths of light in the 5 µm range.

Image Credit: NASA