April 23, 2014

Astro-Vid Of the Week: Landing on Titan

An artist’s conception of Huygens, now silent on the surface of Titan.

(Credit: ESA).

History was made nine years ago today, when the European Space Agency’s Huygens spacecraft successfully landed on Saturn’s largest moon, Titan. Released 20 days prior on Christmas Day, Huygens survived its descent and lasted 1.5 hours on the icy moon’s surface before succumbing to the extreme cold. The probe managed to return images during descent and from the surface, and the feat still stands as the most distant landing on another world to date. [Read more...]

08.06.10: Titan and the Case of the Missing Acetylene.

Titan as imaged by Cassini in 2007. (Credit: NASA/ESA/Cassini).

Titan as imaged by Cassini in 2007. (Credit: NASA/ESA/Cassini).

  

   It started with two papers… as of late, much good and bad science journalism has been committed to the mysteries of Saturn’s largest moon, Titan.  A photochemical smog shrouded world, Titan is a dynamic place, and would easily qualify as a planet in its own right if it were in a solo orbit about the Sun. Titan has only begun giving up its secrets in the past decade; a close flyby of Voyager 1 in 1980 revealed an orange-brown disk devoid of detail. The arrival of the joint ESA-NASA Cassini Huygens mission has led to a wealth of data, as Cassini has performed a series of close mapping flybys of the moon and even deposited the successful Huygens probe on the surface in early 2005. Now, two papers from the Journal Icarus and the Journal of Astrophysical Research describe a curious anomaly; some process is consuming expected acetylene (HC2H) on the surface of Titan. Or something… but wait, let’s not got shouting, “Scientists find life on Titan!” We’re talking an indicator to a possible form of life. The studies site data gathered by Cassini’s infrared spectrometer and ion and neutral mass spectrometer as it swept by the moon. As a matter of fact, Cassini has just completed a 1,270 mile pass recently on June 5th. The process in question is the accumulation of hydrogen molecules high in the atmosphere and raining down to the lakes of methane and ethane coating the surface.  Evidence supports the idea that Titan should be coated with organic molecules, not to be confused with full fledged life itself (old school media take note!). Clearly, something is sequestering the expected acetylene that should be forming… could it be methane-based life? Keep in mind, Titan is a cold place; daytime temps reach a balmy -290 degrees Fahrenheit. Perhaps there may be warmer, as of yet undiscovered pockets of geological activity, but the very idea of methane based life is very hypothetical. Such life forms would be vastly different than what we know here on Earth, and acetylene is on the short list of oxygen-metabolism substitutes. Mark Allen at NASA’s Astrobiology Institute points out that the lack of surface hydrogen and acetylene may have a non-biological cause; “Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed.” Other processes, such as bombardment by radiation or cosmic rays (remember Titan doesn’t have an ozone layer) or the chemical action of minerals could play a role.

So, what should the man on the street take away from this? That Titan is a fascinating and dynamic place, a place in our solar system where things are happening. Clearly, there is more to Titan’s methane- fueled hydrologic cycle than we currently understand, and a spacecraft such as the proposed Titan Survey mission that would put a dirigible-based probe in the atmosphere would go a long way towards solving the “Life on Titan” puzzle. For now, it’ll just have to go on our “Mars-Europa” short-list of interesting places to visit… but don’t believe the “Aliens found on Titan!” news hype just yet!

27.01.10: As Titan Turns.

Sequence showing an evolving storm on Titan. (Credit: Gemini Obs/AURA/H. Roe/E. Schaller).

Sequence showing an evolving storm on Titan. (Credit: Gemini Obs/AURA/H. Roe/E. Schaller).

 

Think that this winter is brutal here on Earth? As February is about to set in, we here at Astroguyz invite you to contemplate the seasons on Titan, the largest moon of Saturn. At over 3,000 miles in diameter, Titan is larger than some planets, and possesses an opaque hydro carbon smog veil of an atmosphere. There, a balmy summer day might reach 290°F on the thermometer, and sunshine is a dim murk at best. Scientists have recently found out that this seemingly dismal world is in fact a dynamic place, and a world well worth further scrutiny. The Cassini spacescraft has already conducted fly-bys of the mysterious moon since its orbital insertion in 2004, and even deposited the Huygens probe, which still stands as the most distant soft landing of a manned spacecraft ever made. Now, scientists Emily Schaller of the University of Hawaii and Henry Roe of the Lowell Observatory have been successful in tracking storms in Titan’s turbulent atmosphere. Like Earth, Titan is one of the very few rocky worlds in the solar system that possesses a hydrological cycle and weather. On Titan, however, it rains liquid methane and pools of ammonia dot the surface of this bizarre world. Using the 3-meter Infra-red Telescope Facility, Schaller and Roe monitored Titan 138 nights over 2.2 years in the 2.1 micron range, using the much more sensitive Gemini North telescope also on Mauna Kea for follow up observations when things started to look interesting. Titan is a tough target to image; at its best, it presents a disk no more than 0.8” in diameter. The 2008 storm pictured about demonstrates that Titan is indeed a changing world, one that deserves further examination. Cassini has already performed another flyby of Titan earlier this month on January 12th as part of its mission extension.

Titan Unveiled by Ralph Lorenz & Jacqueline Mitton

Cover.

A New Look: Three Faces of Titan.    

   Perhaps no world in the Solar System is as enigmatic as Titan. Until the last decade or so, what was known about this distant moon of Saturn could barely fill out a postcard, let alone a book. Titan Unveiled published by Princeton University Press is the first book solely dedicated to the moon, centering mostly on the phenomenally successful Cassini-Huygens mission to the ringed planet. [Read more...]