I recently speculated that spacecraft both orbiting and sitting upon Mars may have already detected signs of life. In particular, some spacecraft have detected signs of methane:
In 2004 the European Space Agency probe Mars Express detected the presence of methane in the atmosphere of Mars. Methane can be produced geologically (and Mars is not short on volcanoes), or biologically. (Though media reports of that observation got a bit out of hand.) Either way, this is an important observation and research on the source of this methane is still ongoing.
The existence of methane is ambiguous: Though methane is produced biologically, as I wrote above, it’s also produced geologically (and, in fact, the methane detected on Mars tends to be both localized and emanating from some of the more volcanic regions). It can also be delivered by comets. Given its ubiquity, methane may raise hopes, but in the end turn out to be a poor biomarker. Detecting life elsewhere will require multiple lines of evidence.
Planets and moons do not give up their secrets willingly or easily — they make us work for every clue we get. That seems particularly true when it comes to the search for extraterrestrial life. Even then, some bodies in the Solar System make us work harder than others.
Take Titan, for example. Two weeks ago, I wrote that observations of Titan from Cassini have been interpreted by some as possible signs of life, in particular:
Now it turns out that computer simulations based upon Cassini observations, simulations which hint at depletions of various chemical species at Titan’s surface may again hint at the possibility of life on Titan. The results are very preliminary, but fascinating nevertheless.
It’s highly unlikely that we’ll ever be able to make a positive determination if there’s life on Titan based upon Cassini data alone. Cassini is, after all, an orbiter, and its observations of Titan’s surface come from hundreds, even thousands, of kilometers away–limited to those that can be attained during flybys. To ascertain the presence of life, we’ll need what scientists in the field of remote sensing call “ground truth”–we’ll have to wait until we are able to send a followup probe to the surface of Titan. Perhaps we’ll send a probe to Titan similar to Tiny–the Titan rover who has guest-starred in episodes of this season’s Eureka.
Even then it could turn out that, unless NASA’s version of Tiny returns samples to Earth for human examination, the results could remain ambiguous and leave scientists scratching their heads. That is what’s happening with Mars.
Titan hides its secrets beneath a thick photochemical haze, but when it comes to planets that jealously guard their secrets, Mars is the champion. The Great Galactic Ghoul of Mars destroys our spacecraft. Mars throws us curve balls; Mars lies to us. Mars even laughs at the spacecraft it does allow to explore it.
It’s a case of actual science passing into the realm of myth. What began as an amazing astronomical affair is now an annoying astronomical aftermath. It’s the “Opposition of Mars this coming August 27th.” Perhaps you got the email? Well the situation is like this…
Every 26 months Mars and Earth are in opposition, meaning that you could draw a (nearly) straight line between the Sun, Earth, and Mars. Although Earth’s orbit is not a perfect circle, if you could see one entire orbit, traced out over an entire year, you would be hard-pressed to tell that it wasn’t a perfect circle. The same can not be said for Mars. Mars has a nontrivial orbital eccentricity — where the term “eccentricity” is a measure of how “out-of-round” an orbit is. So if you could see the orbits of both Earth and Mars traced out, it would look a little like a hard-boiled egg cut down its long axis.
One of my favorite authors (and one of the most scientifically grounded around) is Ben Bova, who has recently published the third book in his trilogy about Mars exploration called Mars Life. The Biology in Science Fiction blog has an interview with Bova, where he talks about the possibility of life on Mars, and why he doesn’t like the idea of terraforming the red planet.
Singing Mad Scientist Alert: Dr. Horrible comes online today and its pretty frakkin’ good. If only Whedon had the foresight to cast NPH in the Buffy musical.
Ahead of our ComicCon panel next week on good science in good science fiction, some musings on the opposite phenomenon: when science fiction hurts good science. [io9, Science Fiction in Biology and Mike Brotherton via SF Signal]
UPDATE: I totally missed the main point of this last story, which was that Buzz Aldrin was the guy who said that popular scifi was hindering science. Active discussion on the topic going on now at Bad Astronomy.
Pixar worked its magic this weekend, shooting to the top of the box office for the ninth consecutive time with WALL-E. And deservedly so–the movie pulls you into its world, and anybody whose heart doesn’t go out to the title character has a soul made of burnt toast. WALL-E is the name of the last robot left cleaning up the garbage-strewn Earth. All the humans left for an intergalactic cruise while the planet was getting spruced up, but the cruise has been going on for 700 years now with no end in sight.
Used to being pampered by robots and never leaving their hover-chairs, the humans have gotten a little bit portly over the centuries, and now find it difficult to even walk (if it ever occured to them to do so). Which is a problem that lurks in the minds of the people who are planning real-life expeditions to Mars.
One of my favorite science-fiction movie scenes is the opening sequence of Armageddon, which depicts the asteroid impact that marked the end of The Dinosaur Show. After the impact, hellfire rains down across the globe in deadly, but photogenic, fashion.
But as impressive a visual as that scence is, it is small beans compared to what scientist think might have actually happened to Mars. After sifting through huge amounts of data sent back from NASA’s Mars Reconnaissance Orbiter and the Mars Global Surveyor probes, scientists believe they are closer to an explanation of one of the great puzzles of the solar system: why the northern hemisphere of the planet is so different from the southern hemisphere.
The southern hemisphere is a jangle of ancient and rough terrain. The surface of northern hemisphere is much younger, and one of the flatest places in the solar system. Suggested explanations include the notion that the northern hemisphere is the sea bed of long-vanished ocean, that lava flows from the interior smoothed out the surface, or that it’s actually just a really big crater from a really, really big asteroid.
A new analysis of the shape of the Northern plain that (and this was the hard part) took into account later volcanic action that distorted the outline over the eons has put considerable weight behind the crater theory. This would make Mars host to the largest crater in the solar system and give us new insight into just how dangerous the early solar system was—it’s believed that an even bigger asteroid collided with the Earth, splitting the planet completely open and splashing off gobs of material that later formed our moon.