Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The sequestration of ethane on Titan in smog particles

Nature volume 443, pages 669–670 (2006)Cite this article

Abstract

Saturn's largest satellite, Titan, has a dense atmosphere of nitrogen with a few per cent of methane1. At visible wavelengths its surface is hidden by dense orange-brown smog, which is produced in the stratosphere by photochemical reactions following the dissociation of methane by solar ultraviolet light. The most abundant of the products of these reactions is ethane, and enough of it should have been generated over the life of the Solar System to form a satellite-wide ocean one kilometre deep2. Radar observations3 have found specular reflections in 75 per cent of the surface spots observed, but optical searches for a sun-glint off an ocean have been negative4. Here I explain the mysterious absence or rarity of liquid ethane: it condenses onto the smog particles, instead of into liquid drops, at the cold temperatures in Titan's atmosphere. This dusty combination of smog and ethane, forming deposits several kilometres thick on the surface, including the observed dunes and dark areas, could be named ‘smust’. This satellite-wide deposit replaces the ocean long thought to be an important feature of Titan.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

References

  1. Niemann, H. B. et al. The abundances and constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe. Nature 438, 779–784 (2005)

    Article  ADS  CAS  Google Scholar 

  2. Lunine, J. I., Stevenson, D. J. & Yung, Y. L. Ethane ocean on Titan. Science 222, 1229–1230 (1983)

    Article  ADS  CAS  Google Scholar 

  3. Campbell, D. B., Black, G. J., Carter, L. M. & Ostro, S. J. Radar evidence for liquid surfaces on Titan. Science 302, 431–434 (2003)

    Article  ADS  CAS  Google Scholar 

  4. West, R. A., Brown, M. E., Salinas, S. V., Bouchez, A. H. & Roe, H. G. No oceans on Titan from the absence of a near-infrared specular reflection. Nature 436, 670–672 (2005)

    Article  ADS  CAS  Google Scholar 

  5. Yung, Y. L. & DeMore, W. B. Photochemistry of Planetary Atmospheres Ch. 5, 6.3 (Oxford Univ. Press, New York, 1999)

    Google Scholar 

  6. Niemann, H. B. et al. The Galileo Probe Mass Spectrometer: composition of Jupiter's atmosphere. Science 272, 846–849 (1996)

    Article  ADS  CAS  Google Scholar 

  7. Niemann, H. B. et al. The composition of the Jovian atmosphere as determined by the Galileo Probe Mass Spectrometer. J. Geophys. Res. 103, 22831–22846 (1998)

    Article  ADS  CAS  Google Scholar 

  8. Fouchet, T. et al. Jupiter's hydrocarbons observed with ISO-SWS: vertical profiles of C2H6 and C2H2, detection of CH3C2H. Astron. Astrophys. 355, L13–L17 (2000)

    ADS  CAS  Google Scholar 

  9. Tomasko, M. G. et al. Rain, winds and haze during the Huygens probe's descent to Titan's surface. Nature 438, 765–778 (2005)

    Article  ADS  CAS  Google Scholar 

  10. Lorenz, R. D. et al. The sand seas of Titan: Cassini RADAR observations of longitudinal dunes. Science 312, 724–727 (2006)

    Article  ADS  CAS  Google Scholar 

  11. Lorenz, R. D., Lunine, J. I., Grier, J. A. & Fisher, M. A. Prediction of aeolian features on planets: application to Titan. J. Geophys. Res. 100, 26377–26386 (1995)

    Article  ADS  Google Scholar 

  12. Griffith, C. A. et al. Evidence for a polar ethane cloud on Titan. Science 313, 1620–1622 (2006)

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

I thank A. L. Sprague, L. Doose and M. Tomasko for discussions. I also thank H. Niemann, the Principal Investigator of the Galileo Probe Mass Spectrometer.

Author information

Authors and Affiliations

  1. Lunar and Planetary Laboratory, The University of Arizona, Tucson, Arizona, 85721, USA

    D. M. Hunten

Authors
  1. D. M. Hunten
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to D. M. Hunten.

Ethics declarations

Competing interests

Reprints and permissions information is available at www.nature.com/reprints. The author declares no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Hunten, D. The sequestration of ethane on Titan in smog particles. Nature 443, 669–670 (2006). https://doi.org/10.1038/nature05157

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature05157

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing