Huygens on Titan

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Saturn's moon Titan — larger than the planet Mercury and with an atmosphere — has always intrigued astronomers. Results exceeded expectations when the Huygens probe deployed its parachutes and drifted down through Titan's chemical haze, revealing bright highlands that drain in a river-like way to flat, dark lowlands, before landing in a material with the consistency of wet sand after a descent of 2 hr 28 min. The first results were published in the 8 December 2005 issue of Nature and this special web focus presents the latest findings alongside a comprehensive archive of papers about this fascinating moon. The sights and sounds of Huygens' incredible journey are also featured in multimedia files including a brilliant descent animation. Supported by ESA. Nature carries sole responsibility for all editorial content. Image: ESA


Current research


Planetary science: Huygens rediscovers Titan Free access

Tobias Owen

Nature 438, 756 (08 December 2005) doi:10.1038/438756a


In situ measurements of the physical characteristics of Titan's environment Free access

M. Fulchignoni et al.

Nature 438, 785–791 (08 December 2005) doi:10.1038/nature04314

An overview of the descent and landing of the Huygens probe on Titan Free access

Jean-Pierre Lebreton

Nature 438, 758–764 (08 December 2005) doi:10.1038/nature04347

The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe Free access

H. B. Niemann et al.

Nature 438, 779–784 (08 December 2005) doi:10.1038/nature04122

Rain, winds and haze during the Huygens probe's descent to Titan's surface Free access

M. G. Tomasko

Nature 438, 765–778 (08 December 2005) doi:10.1038/nature04126

A soft solid surface on Titan as revealed by the Huygens Surface Science Package Free access

John C. Zarnecki et al.

Nature 438, 792–795 (08 December 2005) doi:10.1038/nature04211


The vertical profile of winds on Titan Free access

M. K. Bird et al.

Nature 438, 800–802 (08 December 2005) doi:10.1038/nature04126

Complex organic matter in Titan's atmospheric aerosols from in situ pyrolysis and analysis Free access

G. Israël et al.

Nature 438, 796–799 (08 December 2005) doi:10.1038/nature04349


Titan: tapping the flood of data Free access

As the first analyses of the Huygens mission to Titan are published, Mark Peplow charts the satellite's transition from fogbound moon to familiar landscape, and finds out why scientists long to return.

Nature 438, 538–539 (01 December 2005) doi:10.1038/438538a


Huygens Descent Animation

Touchdown on Titan! Lasting about 1 minute, this descent animation (16.1MB) starts at an altitude of 300 km and follows the eastward trajectory that the Huygens probe travelled along during its journey to Titan's surface. A higher resolution file (35MB) is also available.

Cassini orbiter ISS (Imaging Science Subsystem), RADAR & VIMS (Visual and Infrared Mapping Spectrometer) images are displayed in quick succession followed by DISR (Huygens Descent Imager/Spectral Radiometer) mosaics from increasingly lower altitudes. The longitude/latitude grid lines are separated by 2 degrees.

The surface colour is approximately what a human observer riding along with the probe would see if she or he could see through Titan's atmospheric haze. In the last few kilometres the point-of-view turns south, the direction the Huygens Probe is believed to be facing as it sits on the surface today, and the approximate landing site is marked with a dotted-circle.

The DISR images are relatively unique in the change of scale they display as Titan transforms from a planetary mass to an alien landscape. Three cameras, whose combined field of view was a narrow vertical slice stretching from nadir to horizon, recorded images as fast as they could be transmitted to the Cassini Orbiter. They were projected from above to preserve scale and then projected with a perspective that mimicked what an observer riding the probe would see. Each second of the animation encompasses 30 frames. Credit: ESA/NASA/ASI. Animated by Bashar Rizk, Lunar & Planetary laboratory, University of Arizona.


Huygens Descent Audio

Speeding through Titan's haze
The Huygens Atmospheric Structure Instrument (HASI) onboard the Huygens probe is a multisensor package designed to measure the physical quantities characterizing Titan's atmosphere. During the Huygens' descent (HASI) recorded the average "sound spectrum" (though it is not the same as recorded sound - the acoustic sensor is a pressure transducer). However, data revealed by these 'sounds' might include the rush of the atmosphere, wind, thunder from local storms, the deployment of the probe's braking parachutes, and perhaps the splash of liquid methane rain.
This recording is a laboratory reconstruction of the sounds heard by Huygens' microphones. Several sound samples, taken at different times during the descent, are combined and give a realistic reproduction of what a traveller onboard Huygens would have heard during one minute of the descent through Titan's atmosphere. Credit: ESA/ASI/UPD/IWF.

Radar echoes from Titan's surface
This recording was produced by converting into audible sounds some of the radar echoes received by Huygens during the last few kilometres of its descent onto Titan. As the probe approaches the ground, both the pitch and intensity increase. Aspects of Titan's surface topography can be inferred from the intensity and pattern of the echoes. Credit: ESA/ASI/UPD/CNRS/IAA/RSSD/IWF.



It has now been over six decades since the discovery of Titan's thick atmosphere (although such a possibility was hinted at as early as 1907), during which time this unusual moon has been a continuous source of academic fascination and speculation. Here we bring together a collection of papers on Titan from Nature's archive, illustrating how our views on atmospheric composition, surface properties and - most notably - the tantalizing possibility of liquid oceans have evolved over time.


No oceans on Titan from the absence of a near-infrared specular reflection Free access

R. A. West et al.

Nature 436, 670–672 (04 August 2005) doi:10.1038/nature03824


Planetary science: Shades of Titan

Louise Prockter

Nature 435, 749–750 (09 June 2005) doi:10.1038/435749a


Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan

C. Sotin et al.

Nature 435, 786–789 (09 June 2005) doi:10.1038/nature03596


Imaging of Titan from the Cassini spacecraft

Carolyn C. Porco et al.

Nature 434, 159–168 (10 March 2005) doi:10.1038/nature03436


Direct detection of variable tropospheric clouds near Titan's south pole Free access

Michael E. Brown et al.

Nature 420, 795–797 (19 December 2002) doi:10.1038/nature01302

A wind origin for Titan's haze structure

P. Rannou et al.

Nature 418, 853–856 (22 August 2002) doi:10.1038/nature00961

Stable methane hydrate above 2 GPa and the source of Titan's atmospheric methane

J. S. Loveday et al.

Nature 410, 661–663 (05 April 2001) doi:10.1038/35070513


Planetary science: Titan weather report

F. Michael Flasar

Nature 395, 541–543 (08 October 1998) doi:10.1038/26847


Transient clouds in Titan's lower atmosphere

Caitlin A. Griffith, Tobias Owen, Gary A Miller, Thomas Geballe

Nature 395, 575–578 (08 October 1998) doi:10.1038/26920

Tidal effects of disconnected hydrocarbon seas on Titan

Stanley F. Dermott, Carl Sagan

Nature 374, 238-240 (16 March 1995) doi:10.1038/374238a0

Evidence for surface heterogeneity on Titan

Caitlin A. Griffith

Nature 364, 511-514 (05 August 1993) doi:10.1038/364511a0

Meteoroid ablation processes in Titan's atmosphere

W-H. Ip

Nature 345, 511-512 (07 June 1990) doi:10.1038/345511a0

Upper limit set for level of lightning activity on Titan

M. D. Desch, M. L. Kaiser

Nature 343, 442-444 (01 February 1990) doi:10.1038/343442a0


An occult view of Titan

James Elliot

Nature 343, 315-316 (25 January 1990) doi:10.1038/343315a0


Probing Titan's atmosphere by stellar occultation

B. Sicardy et al.

Nature 343, 350-353 (25 January 1990) doi:10.1038/343350a0

Results for Titan's atmosphere from its occultation of 28 Sagittarii

W. B. Hubbard et al.

Nature 343, 353-355 (25 January 1990) doi:10.1038/343353a0

High-temperature shock formation of N2 and organics on primordial Titan

Christopher P. McKay et al.

Nature 322, 520-522 (07 April 1988) doi:10.1038/332520a0

D to H ratio and the origin and evolution of Titan's atmosphere

Joseph P. Pinto, Jonathan I. Lunine, Sang-Joon Kim, Yuk L. Yung

Nature 319, 388-390 (30 January 1986) doi:10.1038/319388a0

Organic synthesis in the atmosphere of Titan Free access

S. Gupta, E. Ochiai, C. Ponnamperuma

Nature 293, 725-727 (29 October 1981) doi:10.1038/293725a0

Formation of organic molecules on Titan

Louis A. Capone et al.

Nature 293, 45-46 (03 Sep 1981) doi:10.1038/293045a0


Titan's atmosphere: temperature and dynamics

F. M. Flasar, R. E. Samuelson, B. J. Conrath

Nature 292, 693-698 (20 August 1981 doi:10.1038/292683a0

C3H8 and C3H4 in Titan's atmosphere

W. C. Maguire, R. A. Hanel, D. E. Jennings, V. G. Kunde, R. E. Samuelson

Nature 292, 683-686 (20 August 1981) doi:10.1038/292683a0

Implications of Titan's north-south brightness asymmetry Free access

Nature 292, 698-702 (20 August 1981) doi:10.1038/292698a

C4H2, HC3N and C2N2 in Titan's atmosphere

V. G. Kunde et al.

Nature 292, 686-688 (20 August 1981) doi:10.1038/292686a0

Mean molecular weight and hydrogen abundance of Titan's atmosphere

R. E. Samuelson et al.

Nature 292, 688-693 (20 Aug 1981) doi:10.1038/292688a0


Effect of Noble Gases on an Atmospheric Greenhouse (Titan)

Robert Cess and Tobias Owen

Nature 244, 272-273 (03 August 1973) doi:10.1038/244272a0