Astronomers say the cloud contains frozen particles of a highly toxic compound dubbed hydrogen cyanide

Oct 2, 2014 06:52 GMT  ·  By

A paper published in yesterday's issue of the journal Nature announces the discovery of a massive poisonous cloud on Titan, Saturn's largest moon. The cloud, identified with the help of NASA's Cassini spacecraft, is said to be hovering over Titan's south pole.

What's really weird about this cloud is that it formed at an altitude of about 200 miles (roughly 300 kilometers) above Titan's surface. As explained by scientists, clouds on this distant moon do not usually form at such impressive heights.

“We really didn't expect to see such a massive cloud so high in the atmosphere,” specialist Remco de Kok of Leiden Observatory and SRON Netherlands Institute for Space Research commented on this find in an interview.

Not your run-off-the-mill cloud

Data obtained with the help of NASA's Cassini spacecraft indicates that this giant cloud swirling over Titan's south pole contains frozen particles of a poisonous chemical compound known to the scientific community as hydrogen cyanide.

Researchers have long been aware of the presence of this compound in Titan's dense atmosphere. However, the hydrogen cyanide thus far documented on this moon presented itself as a gas. Hence, scientists were quite surprised to find frozen particles of this chemical.

In their paper in the journal Nature, the scientists behind this research project explain that, in order for hydrogen cyanide to freeze, it must be exposed to temperatures at least as low as -234 degrees Fahrenheit (-148 degrees Celsius).

Having discovered this cloud containing frozen hydrogen cyanide on Titan, specialists can only conclude that this moon is a much colder place than assumed. As Remco de Kok put it, “The discovery suggests that the atmosphere of Titan's southern hemisphere is cooling much faster than we expected.”

How Titan is kind of like Earth

Unlike other moons in the Solar System, Titan experiences seasons as it moves around the Sun together with its host planet, Saturn. Since this moon has a 29-year orbit, each of the seasons Titan traverses lasts over 7 years.

By the looks of it, Titan last switched seasons back in 2009, when its northern hemisphere transitioned from winter to spring and its southern hemisphere switched from summer to autumn. The low temperatures that made it possible for the massive poisonous cloud to form are believed to have been the result of such seasonal changes.

Thus, astronomers say this cloud likely came into being due to a combination of factors: the changing of seasons caused shifts in atmospheric circulation and brought a large mass of gas to the moon's south pole, and reduced exposure to sunlight triggered a temperature drop that translated into the formation of the frozen hydrogen particles included in the makeup of Titan's peculiar cloud.

NASA image shows huge, swirling cloud hovering over Titan
NASA image shows huge, swirling cloud hovering over Titan

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A toxic could is swirling over Titan's south pole, NASA says
NASA image shows huge, swirling cloud hovering over Titan
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