April 21, 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...]

03.04.11: Alien or Aeolian?

The humble terrestrial sand dune…(Credit: Art Explosion).

This sunny Sunday morning, we’d like to point you towards an astro-video that floated through our cyber-transom. We’ve recently discovered the SETI Talks series on YouTube, and have become a hooked subscriber. These weekly talks feature a broad range of astronomers and researchers and are a fascinating look at cutting edge science as expressed by the scientists that are doing the research. [Read more...]

18.02.11: A Titan(ic) Flyby.

Titan (Lower Left) paired with Saturn as seen from Cassini last year. (Credit: NASA/Cassini/JPL/The Space Science Institute).

Far out in the depths of the solar system, one of our most distant orbiting ambassadors is completing a flyby of the largest known moon. On Friday, February 18th at 11:04AM EST NASA’s Cassini orbiter will skim the Saturnian moon at a distance of just 2,270 miles above the enigmatic moon Titan. [Read more...]

AstroEvent(s): A Week of Moons, Tri-Conjunctions, & Lunar Features!

Venus, Vesta, & Pluto in a 5 degree field of view. (Created by Author in Starry Night).

This week offers a grab bag of unique events, far from the humdrum wide conjunctions and difficult to see pairings. The action starts on February 8th with a rare chance to see Saturn’s moons in 1 -8 order. This occurs in a narrow window from 19:01-19:38 UT, and thus favors the Asian Far East. The planet currently rises around 11PM local, and a majority of the moons should still be in order from your corresponding latitude. [Read more...]

05.02.11: Postcards from Saturn.

Rhea and friends…(Credit: Cassini/NASA/JPL).

Ahhhh, but to be a fly aboard a Saturn-circling mission… this weekend, I want to turn your attention to some fairly amazing imagery coming from NASA’s Cassini spacecraft in orbit about Saturn. Cassini has just completed a flyby of several moons, including Enceladus, returned some first ever images of the tiny moon Helene, and on January 11th, took the close-up of Rhea pictured above. [Read more...]

AstroEvent: The Return of the SEB?

Great Red Spot+SEB as seen from Astroguyz HQ. (Photo by Author).

 

   Followers of this column know that Jupiter has appeared rather odd during this years’ 2010 apparition. Specifically, the Southern Equatorial Belt, or SEB, vanished for the first time in the 21st century. This is not a unique or singular occurrence, as it happened no less than 12 times in the 20th century. It’s not completely understood why this happens, and why only the SEB is prone to this disappearing act and never its twin Northern Equatorial Belt. Now, there’s evidence that the SEB may be returning. [Read more...]

Review: Journey Beyond Selene by Jeffery Kluger.

A classic of the early space age!

        A classic of the early space age!

     Before men landed on the Moon, we had to first crash land there successfully. This week, we dip back into the Astroguyz library to review the classic Journey Beyond Selene: Remarkable Expeditions Past Our Moon and to the Ends of the Solar System by Jeffery Kluger. We dug this gem up from our favorite Tucson haunt Bookman’s years ago. Selene tells the fascinating tale of the evolution of the unmanned space program. [Read more...]

Astro-Challenge: See Saturn’s Moons in 1 to 7 Order.

Saturn's moons on July 31st. (Created by the Author in Starry Night).

Saturn's moons on July 31st. (Created by the Author in Starry Night).

 

    This week’s challenge may also give you a unique photographic opportunity. On the evening of July 31st (my birthday!) Saturn’s moons will be in 1 to 7 order. This will occur from 6:45 to 11:15 Universal Time, and favor viewers in Australia and the Far East. Later in the evening over North America, only speedy Mimas and Enceladus will be out of order… now is the time to brush up on and perhaps nab some of those hard to spot moons; in descending magnitude, difficulty, and order number (#)  they are: [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!

14.04.10: Milankovitch Cycles…On Titan?

 

(Credit: NASA/JPL/University of Arizona).

(Credit: NASA/JPL/University of Arizona).

An amazing sight; sunlight reflected off the Kraken Mare caught by Cassini! 

   NASA’s Cassini spacecraft has revealed an elusive mystery on the surface of Titan; namely, why does the northern hemisphere of the large moon contain numerous lake basins, while in the south they’re relatively scarce? Now, scientists at Caltech working with JPL think they may have an answer. These lakes show up as bright (empty) and dark (filled) patches as the Cassini spacecraft pings them with its Synthetic Aperture Radar (SAR). Of course, on Titan, the hydrologic chemical of choice is liquid ethane and methane, and it is thought that some transport mechanism results in a net flow imbalance between the two hemispheres. Seasons on Titan last roughly 15 years as it dances around Saturn in its 29.5 year orbit about the Sun. But simple seasonal drainage of about a meter per year couldn’t empty the 100 meter-plus deep basins in a single season. This also doesn’t account for the overall disparity in number of basins seen, both filled and unfilled. Instead, scientists point towards the eccentricity of Saturn’s orbit as the possible cause. Saturn’s eccentricity is 0.055, or a little over 5% deviation from a perfect circle. This would make for periodic inequalities in the seasons, much like what occurs on Earth. For example, the perihelion of Earth actually occurs in northern hemisphere winter, somewhat ameliorating the severity of the seasons. But the variation of eccentricity coupled with the obliquity of the planetary spin axis and the precession of the equinoxes can vary over geologic time scales, causing variations in the climate. This is known as the Milankovitch cycle, and is thought to be a major contributing factor to the onset of Ice Ages. On Titan, a similar process is thought to occur, resulting in a net imbalance over thousands of years in the methane flow cycles between the two hemispheres. We may now simply be observing Titan during an epoch when seasonal methane pooling favors the northern hemisphere. Whatever the case, Titan is proving to be a fascinating and changing world deserving of further scrutiny.

14.03.10-Record Lightning Storm Spotted by Cassini.

The shadow of Titan as viewed by Cassini. (Credit: NASA/JPL/Space Science Institute).

The shadow of Titan as viewed by Cassini. (Credit: NASA/JPL/Space Science Institute).

 

Saturn is turning out to be a very electrified place. Last year, NASA’s Cassini orbiter spied a massive storm that broke the solar system record; beginning in January 2009, this storm raged on for 7 ½ months, the longest recorded. This marks the ninth storm on Saturn thus recorded; these behemoths tend to be around 1,900 miles in size. It’s been known since the initial Voyager flybys of the ringed world in the 1970’s that an ionization differential of x100 exists in favor of the daytime side of Saturn over its night side, but routine observations by Cassini are revealing what a turbulent world Saturn really is. Cassini utilizes its antennae aboard its Radio and Plasma Wave Science instrument to analyze the powerful radio emissions.   Tantalizingly, the storms almost always originate in a region known as “Storm Alley” at latitude 35° south. The reason for this isn’t entirely clear. Scientists also took advantage of a passage of Cassini behind Saturn’s largest moon, Titan, to confirm the source of these radio emissions. Surely enough, when Titan occulted the body of Saturn, the emissions disappeared, only to return when Saturn came back into view. This was yet another proof that Saturn is still an active and mysterious place.

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.

January 2010: Life in the Astro-Blogosphere.

Not bad for a first try; The Orion Nebula! (Photo by Author).

Not bad for a first try; The Orion Nebula! (Photo by Author).

Ahhhh…. Another decade is upon us. It’s hard to believe that only ten brief years ago, we had yet to land a probe on Titan, only a handful of exo-planets were known, cell phones were bricks, and a “Gig” was still the pinnacle of computing power. As 2010 is upon us, we realize that we have yet to travel in air locks or have phasers at ready on our hips. Of course, science has made some of our futuristic dreams come true; we now routinely don more computing power on our ears than sent man to the moon, and everything is made of plastic… [Read more...]

Review: The Quiet War by Paul McAuley.

Out this month from Pyr Books!

Out this month from Pyr Books!

One all-pervasive theme that waxes and wanes in the sci-fi genre more than warrior-maidens’ hemlines is the role of warfare in the future of humanity. This concept swings from the space war operas spawned in the pulp era of the 30-40s to the doctrine of a “shinny happy future” as an antidote to the Cold War era. War seems to be on the upswing again, perhaps as an extension of the human condition and the impact of the current Global War on Terrorism on the popular psyche. The Quiet War by Paul McAuley and out this month by Pyr Books takes the concept of warfare out into the Solar System of the semi- near future. [Read more...]

September 2009:News & Notes.

An image of of the giant star Betelgeuse! (Credit: Hubble/NASA/ESA).

An image of of the giant star Betelgeuse! (Credit: Hubble/NASA/ESA).

Is Betelgeuse shrinking? Everyone’s favorite candidate for a nearby supernova has been exhibiting some alarming behavior as of late. The red giant star Betelgeuse, located in the shoulder of Orion, has decreased in size by 15 percent since 1993, equating to a loss of 1% of diameter per year. The finding comes from monitoring conducted by researchers at the University of Berkeley using the Infrared Spatial Interferometer atop Mount Wilson. This shrinkage is all the more stupefying when one considers that recent research places Betelgeuse at a distance of 640 light years, making this bloated star over 5 astronomical units in diameter! AAVSO volunteers that have been monitoring the star have noted that the shrinkage has not been accompanied by a magnitude drop. [Read more...]

Astro-Event of the Week; March 9th-15th; A Transit of Titan.


Titan Transit.

The Situation at 06:22 AM EDT on Thursday the 12th…(Credit Starry Night).

This week’s astro event is a special one. Anyone who has been tracking the planet Saturn as of late knows that the ring plane is nearly edge on. One consequence of this is a series of rare transits are underway, and one of the best occurs this week. Saturn’s largest moon, Titan will transit Saturn’s disk for viewers in North American longitudes westward in the early AM hours of Thursday, March 12th, 2009. [Read more...]