* Astronomy

Title: Organic haze on Titan and the early Earth
Authors: Melissa G. Trainer, Alexander A. Pavlov, H. Langley DeWitt, Jose L. Jimenez, Christopher P. McKay, Owen B. Toon, and Margaret A. Tolbert.

Recent exploration by the Cassini/Huygens mission has stimulated a great deal of interest in Saturn's moon, Titan. One of Titan's most captivating features is the thick organic haze layer surrounding the moon, believed to be formed from photochemistry high in the CH4/N2 atmosphere. It has been suggested that a similar haze layer may have formed on the early Earth. Here we report laboratory experiments that demonstrate the properties of haze likely to form through photochemistry on Titan and early Earth. We have used a deuterium lamp to initiate particle production in these simulated atmospheres from UV photolysis. Using a unique analysis technique, the aerosol mass spectrometer, we have studied the chemical composition, size, and shape of the particles produced as a function of initial trace gas composition. Our results show that the aerosols produced in the laboratory can serve as analogs for the observed haze in Titan's atmosphere. Experiments performed under possible conditions for early Earth suggest a significant optical depth of haze may have dominated the early Earth's atmosphere. Aerosol size measurements are presented, and implications for the haze layer properties are discussed. We estimate that aerosol production on the early Earth may have been on the order of 10^14 g·year^–1 and thus could have served as a primary source of organic material to the surface.

Source

This image of Titan was taken by the Cassini spaceprobe on October 23, 2006, when it was approximately 948,337 kilometers away.


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Credit NASA

The image was taken using the P60 and BL2 filters.

Flooded rivers and more lakes have been spied on Saturn's moon Titan in new images by the Cassini spacecraft. The features are all likely filled with liquid methane or ethane, providing insight into a methane cycle analogous to the hydrological cycle on Earth.

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This image of Titan was taken by the Cassini spacecraft on October 10, 2006, when it was approximately 602,695 kilometres away.


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Credit NASA

The image was taken using the IRP0 and CB3 filters.