Scientists Discuss Results from Titan Landing

Imagine a frigid world where complex hydrocarbon particles clump together in the thick smog-like atmosphere and fall like black snow onto a light water ice surface. Occasional methane rains and methane springs that emerge from the side of hills wash some of the particles off higher ground and concentrate them in river channels. These rivers flow through the hills to lower-lying areas. Some of the liquid methane with its hydrocarbon particle load collects into pools and lakes. Eventually, the liquid evaporates or soaks into the ground, until the pools are dry, waiting for the next rainfall.

Titan is that world, revealed this morning by scientists involved with the Huygens space probe mission. After last week’s successful landing on the exotic Saturnian moon, data from the probe’s mass spectrometer, imaging system and other sensors confirmed the presence of liquid methane on or near the surface of Titan. Because Huygens detected methane just a few centimeters below the surface, scientists believe that it may have rained recently in the area, perhaps in the few days or weeks before the landing.

Marty Tomasko, Principle Investigator for the Descent Imager-Spectral Radiometer (DISR) on board Huygens, stated that Titan was a world of “earth-like processes” using “exotic materials.” Instead of water, methane is the primary liquid at work on the surface of the moon, and rather than silicate rocks, the rocks of Titan are made of water ice. They interact to create breathtaking vistas such as those near the Huygens landing site: river channels flowing down ridges to temporary lowland lakes with distinct shorelines.

Because no current pools of liquid were detected on the surface, the region photographed by Huygens may be a relatively more arid region of Titan, though little is known about the rest of the moon to substantiate this theory. The region may resemble the deserts of Arizona, where liquid water plays an important role in shaping the landscape despite the aridness, resulting in dry river beds between episodes of seasonal flooding.

“Do You Like Movies About Gladiators?”

New Scientist reports this week on the work of archaeologist Steve Tuck of the University of Miami who suggests that the combat of gladiators in ancient Rome might have been all show, perhaps more WWE than a bloody fight to the death. Dr. Tuck examined the many examples of art from the period that depicted this combat and found that they resembled images in martial art guides from other periods and cultures. These step-by-step guides were used for the artistic expression of fighting skills rather than killing the opponent. Other lines of evidence include indications that gladiators at the time were too well paid to suffer real harm. Of course, not every expert agrees.

The modern historian uses science to learn what actually happened rather than relying on reports from often subjective contemporary observers. Like all scientific fields of inquiry, history has seen its own share of breakthroughs, surprises, and controversies of late.

Mars Meteorite in Color

Opportunity continues to study the first meteor discovered on another planet. NASA released a color image of the metallic body sitting in martian sands. The pitted meteorite is composed of iron and nickel, just like metallic meteorites that land on the Earth. Yet to be determined is how rare the object is, whether or not the rate of meteor falls on Mars is different from the Earth, the history of impact and erosion on the meteorite, and how long the meteorite might have been sitting there, waiting for Opportunity to stumble across it.

Meteorite on Mars

It should not be too surprising that meteorites are not just rocks that have fallen from space to a final resting place on the surface of the Earth. Meteoroids fall on bodies throughout our solar system. Opportunity, the rover currently at work on Mars, recently came across a metallic-looking rock lying in the desert sands of Meridiani Planum. Steve Squires, primary science investigator for the Mars Exploration Rover (MER) mission, recently confirmed to various publications that the rock is a meteorite. It has an iron-nickel composition.

Although not a native martian object, the meteorite could reveal something about the martian atmosphere at the time it fell to Mars. Opportunity will spend some time with the meteorite to gather further data.

Apple Aggressively Attacks

Hoping to increase Apple’s market share and bring their products to the masses, Steve Jobs announced several new products last week, including a computer beginning at US$499 and a flash memory-based iPod beginning at US$99. While Apple’s iPod has been a big seller over the past few years, few purchasers have made the transition from PC computers to Apple computers. With the Mac mini and iPod shuffle that could change quickly.

The Mac mini was designed for people ready to make the transition from PC computers to Apple computers. The 6.5-inch by 6.5-inch by 2-inch box allows buyers to attach the mouse, keyboard and monitor they already own.

The iPod shuffle holds up to 120 on the 512MB version and up to 240 songs on the 1GB version. Designed for those who enjoy shuffling their music playlist, the iPod shuffle has no LCD screen and is smaller than most packs of gum. Apple aimed the newest iPod at the 30 percent market share of personal music players that they do not already own.

The iPod shuffle and Mac mini are available for purchase now on the Apple Store website and will be available in most Apple Store retail locations on January 22, 2005.

Open-Source Titan

One of the early promises of the Information Age was contained in the adage “information wants to be free.” The massive transfer of data to digital formats and the Internet, the rapid explosion in memory capacity and communication bandwidth, and the falling price of technology are related trends reshaping humankind’s relationship with knowledge. The latest example is the public availability of raw images from the current space probe missions, including Cassini-Huygens at the Saturnian system.

In a surprising turn, imaging enthusiasts and amateurs outside ESA and NASA are beating the space agencies at turning the raw data returned by the Huygens space probe from the surface of Titan into breathtaking panorama, mosaics, cleaned-up single images, 3D renderings, and anaglyphs. These images are not official, but reflect the remarkable abilities of these individuals, most of them in Europe. The public seems to be responding; traffic has slowed down the servers of these enthusiasts to a crawl.

The most popular site appears to be anthony.liekens.net, where various contributors have sent in their weekend work. The number of images dwarfs the available images from ESA and NASA. From the site:

“This work has been done by amateurs with no extensive scientific background, publishing the first images in under 8 hours. We’ll have to wait for ESA/NASA to deliver us the correct images, so please, take the resulting images on this page with a grain of salt (that was a disclaimer).”

Impatience and enthusiasm have never come together so beautifully.

The Shores of Titan

A new composite image from Titan appears to show a shoreline where river channels or canyons empty into a black sea. Huygens took the image as it was drifting down toward the surface. Scientists have not yet been able to confirm whether or not the black sea-like region and apparent river channels are full of liquid.

Scientists also pieced together a full 360-degree panorama around Huygens as it drifted out over the black sea-like body. On the left are the channels and shoreline and just right of center is the spot where Huygens landed.

Unlike Mars, where old river beds are billions of years old and show little or no evidence of recent fluvial activity, evidence from the Titan landing site strongly suggest recent fluvial activity. Should scientists confirm that liquid currently exists on its surface, Titan would become only the second known body after the Earth to have such conditions. On Titan, however, the liquid would likely be methane or ethane, rather than water. Because of the extremely cold conditions on Titan, H20 there is solid and the primary mineral in the moon’s rocks.

Titan’s Surface in Color

Dr. Lyn Doose, Co-Investigator of the Descent Imager-Spectral Radiometer (DISR) instrument on the Huygens probe, presented to a packed crowd tonight at the University of Arizona’s Kuiper Space Sciences Building the first scientific results from Friday’s successful landing on Titan. Highlights of his speech included the display of the first images from the surface of Titan, revealing an orange-color world with a thick atmosphere, rock-like pebbles likely composed of ice, and evidence for rivers and seas of liquid methane or ethane.

The DISR instrument was designed to photograph images as the probe descended by parachute through Titan’s atmosphere before impacting the ground. Dr. Doose stated that he had not been confident that the probe would survive the impact and was surprised that Huygens continued to take images for at least a half hour after it came to rest on the surface. According to Dr. Doose, other surprises include the buffeting Huygen’s took during descent by Titan’s winds, apparent images of methane fog, and the terrain that makes Titan look more like the Earth than other moons in our solar system.

The first color image was created by combining reflective spectra data compiled by Dr. Doose and a colleague with a black and white image previously released by the European Space Agency (ESA). The image depicts the color a human would see from the surface of Titan. Titan has a thick atmosphere of nitrogen and methane, which contribute to the color. The image also shows pebble-sized chunks of rock, likely made out of water ice. The roundness of the pebbles suggests deposition by fluvial processes, perhaps by flows of liquid methane.

During the question-and-answer session that followed Dr. Doose’s talk, a young boy asked what the planet would smell like. Dr. Doose answered that methane is odorless, though other hydrocarbons present in the atmosphere of Titan might contribute to a distinctive smell. He said that because methane is odorless, companies here on the Earth that supply natural gas (of which methane is a primary component) must add a signature odor as a safety measure so that people can smell a leak.

Entitled “Descending to a New World”, the free public event was sponsored by the Planetary Image Research Laboratory (PIRL) and the Department of Planetary Science Lunar and Planetary Laboratory (LPL) at the University of Arizona through LPL’s public outreach program. Guests included members of the team from Lockheed Martin, the company that built DISR. Because of the unexpectedly high public turnout, organizers scrambled to set up a second projector in the atrium outside the auditorium within which Dr. Doose spoke. Waiting for the first images from Titan to be displayed on the screen, people stood shoulder-to-shoulder on several floors of the atrium. A follow-up presentation entitled “New Discoveries on Titan” is planned for next Saturday in the same location.

Rivers and Seas on Titan?

Elated scientists are now examining the data sent from the surface of Titan by the Huygens probe. The first image was displayed in special video coverage from the European Space Operations Centre (ESOC) in Darmstadt, Germany. The image appears to show a drainage system emptying into a dark body, though this has not yet been confirmed. Scientists had previously lowered their expectations for finding liquid on the surface of Titan after previous images from Cassini failed to show any obvious signs of oceans or lakes.

Huygens has a much better vantage point than Cassini did because it fell through the moon’s atmosphere to the surface, snapping pictures along the way. Images beneath the haze layer that covers the moon are expected to show great detail. Despite being designed to last for just a few minutes once it landed on the surface, Huygens lasted for over two hours. In fact, it was still sending data to Cassini (to be transmitted later to Earth) when Cassini traveled below the horizon, cutting off the signal. Radio telescopes on the Earth continued to pick up Huygens’ carrier signal hours after the successful landing.

The European Space Agency (ESA) developed the Huygens probe that rode with Cassini to the Saturnian system.