Cassini's data reveal another feature that suggests that Titan is similar to Earth

A dust storm crosses the surface of Titan in this representation of the artist. Image Credit: IPGP / Labex UnivEarthS / Paris Diderot University – C. Epitalon & S. Rodriguez

Analysis of the data returned by the Cassini The spacecraft, which has revolved around Saturn for 13 years, confirms the giant's existence Sandstorm in the equatorial regions of Saturn's largest moon, Titan.

The discovery makes Titan the third world of our solar system known to harbor dust storms (the other two being Earth and Mars).

Sebastien Rodriguez of University Paris Diderot In France, a team of scientists studied luminous regions appearing in the infrared images of equatorial Titan regions captured during the northern equinox of the Great Moon in 2009.

Imaging dust storms on Titan's surface. Image Credit: NASA / JPL-Caltech / University of Arizona / Paris Diderot University / IPGP / S. Rodriguez et al. 2018

Sometimes considered an analogue of the primitive Earth, Titan has a hydrological cycle but, rather than being made up of water, methane is the driving substance. For this reason, Rodriguez and his colleagues initially interpreted the bright regions they saw near Titan's equator as clouds of methane. Such clouds are formed at the equinox of Titan, when the sun passes directly on the equator of the moon. This produces clouds of methane and storms in the tropical regions of the moon, Cassini.

However, a careful study of these light regions indicates that they are not caused by methane clouds, which form at much higher altitudes than those observed only 6 km above the surface of Titan.

"From what we know about cloud formation on Titan, we can say that these methane clouds in this region and at this time of year are not physically possible. The convective methane clouds that can develop in this area and during this period would contain huge droplets and must be at a very high altitude, well above the 10 km that modeling tells us that the new features are localized. " Rodriguez explains.

The chemical signatures of these clear zones do not match those of methane or lava ice, both of which are visible on the surface of Titan much longer than the 11 hours to 5 weeks when these features were observed.

Using computer models, scientists determined that the luminous characteristics were in Titan's atmosphere, but very close to its surface. Their position directly above the equatorial dunes indicates that they are clouds and dust storms raised by the surface winds of the dunes.

Produced by chemistry in Titan's atmosphere, complex organic molecules grow until they fall on the surface of the great moon, before being lifted out of large surface dune fields.

"Titan is a very active moon. We already know about its geology and its exotic hydrocarbon cycle. Now we can add another analogy with Earth and Mars: dust storms, "Rodriguez said.

Deposited on the surface of Titan in 2005, the Huygens the probe only got one wind surface measurement, which was very low. Rodriguez and his colleagues think that Titan's surface winds are much more powerful than Huygens measured, strong enough to trigger dust storms and carry dust over long distances.

"The near-surface wind speeds needed to raise such a large amount of dust as we see in these dust storms should be very strong – about five times stronger than the average wind speeds estimated by the Huygens measurements near the surface and with climate models, "said Rodriguez. "For the moment, the only satisfactory explanation for these strong surface winds is that they could be related to the strong gusts that can occur in the face of the huge methane storms we see in this region and this season."

A similar phenomenon occurs on Earth, with dust clouds often appearing before storms in dry areas.

The results of the study were published in the journal Geoscience of nature.

Tagged: Cassini Dust Storm storm storm Huygens Moon Planet Saturn space The Titan range

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Laurel Kornfeld

Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, New Jersey, who loves writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a scientific certificate from Astronomy Online at Swinburne University. His writings have been published online in The Atlantic, the Astronomy magazine's blog section, the British Space Conference, the 2009 IAU General Assembly Journal, The Space Reporter, and bulletins from various astronomy clubs. She is a member of Amateur Astronomers, Inc. based in Cranford, New Jersey. Particularly interested in the outdoor solar system, Laurel made a short presentation at Great Planet Debate 2008 at the Applied Physics Laboratory