An image of Saturn's moon taken by Cassini. Image:, NASA
Reading With Cassini-Huygens spacecraft data, scientists have elucidated new details about the atmosphere of Saturn's moon Titan: its atmosphere contains molecules that shield the sun's UV rays? similar to the protective ozone layer of the earth. These molecules, called polyins, are formed by particle collisions, the researchers found. They succeeded in simulating this reaction in the laboratory and thus developed a new theory for the formation of polyynes. The atmosphere of Titan is of great interest to researchers, because the conditions on Saturn's Moon are similar to those on Earth shortly after their formation. Cassini has been orbiting Titan since 2004 and will be taking pictures of the moon and collecting data until 2010. The Huygens landing capsule was named after the Dutch explorer of the Moon, which is located around 1.2 million kilometers around the gas planet Saturn. It provides data from which researchers hope to obtain new information about the formation of the Earth's atmosphere. Because apart from the earth, astronomers have so far only known two celestial bodies with a solid surface, which also have an atmosphere, ie an air layer that tightly envelops the planet and rotates with it: Titan and Venus.

The atmosphere of Saturn's Moon contains a high concentration of suspended particles and surrounds it as an orange-brown shell. Some of these so-called aerosols, which can also serve as condensation nuclei for clouds, absorb the UV light of the sun. There are various theories for their creation, some of which contradict each other. The Hawaiian scientists were now able to clarify the question of how these UV-absorbing polyyne molecules originated in the Titan atmosphere. In their experiments, they shot the individual constituents of the polyynes at supersonic speed into a chamber filled with the gas deuterium. They allowed the molecular currents to collide and examined the weight and speed of the resulting products. The researchers found that collisions of individual particles give the polymers with the triple bonds.

This chemical reaction takes place without energy being required. This explains how titanium can connect to each other on Titan. If there were a barrier that must first be overcome by some form of energy, as is the case with many other chemical reactions, this might prevent the formation of the polyyne molecules. During the experiments, the researchers used very sensitive instruments to monitor the changes in energy levels during the individual reaction steps.

Xibin Gu (University of Hawaii in Manoa) et al .: PNAS (doi: 10.1073 / pnas.0900525106). ddp / Martina Bisculm advertisement


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