I found this blog post over at The Planetary Society discussing an increasing daytime upper atmospheric temperature in the southern hemisphere of Mars.

Right now Mars is well into its northern autumn or southern spring. This means that, due to the tilt of Mars (about the same as Earth's), the southern pole is beginning to be pointed more directly towards the Sun. The increasing sunlight leads to increasing temperatures both on the ground and in the atmosphere. It also turns out that as the south moves into summer, the heating is even greater than it is in the north since Mars is about 35 million miles closer to the Sun (Earth's orbit varies by only about 5 million miles).

The heating and pressure difference during southern summer can loft dust up into the air. This dust can heat up very quickly during the day but it also cools quickly overnight. So if there is an increasing amount of dust in the air, we would expect to see more summer heating in the daytime atmosphere than in the night time atmosphere.

Well, the Mars Climate Sounder aboard the Mars Reconnaissance Orbiter is seeing just that. The MCS measures the amount of infrared light emitted by the martian atmosphere by looking at the limb of the planet—so the background is just cold, dark, space.

You can check out the changing MCS measurements over the last few days and see the images at the team blog site noted above.

A fellow MarsWatch'er pointed me to notices of some very interesting work that has been presented at the 40th Annual Lunar and Planetary Science Conference (I don't usually go to this meeting and had not yet gone over the abstracts). The work itself was presented on 23 March and reported on rather quickly by friend-of-planetary-science Kelly Beatty at Sky & Telescope.

It appears that some photos of the leg strut of the Mars Phoenix lander showed what appear liquid drops clinging to it. What makes this so amazing is that water on Mars simply can not exist in the liquid phase. Why is that? It's due primarily to the atmospheric pressure. For example, if you put water into a pot and seal a lid on it, you can heat that water far above the standard boiling point, and thus cook food faster—that how a pressure cooker works in your kitchen. On the other side, those who have lived at altitude know that water boils at a lower than normal temperature. Back when I was in Laramie, Wyoming we used to have fun watching students' faces when they measured the boiling temperature in the lab. It never reached 100°C but instead boiled in the low 90's. This is one reason for "high altitude" baking directions.

The lower boiling point is because there is less air pressure above the liquid making it easier for individual water molecules to leave the liquid surface. It also depends on the local humidity, but that is temperature and pressure dependent as well. So now if we go to Mars where the air pressure is about 1% that of Earth, it is very easy for water molecules to leave a liquid surface; in fact, individual molecules can easily leave a solid surface so the ice will simply sublime away. You can see this effect in your own freezer if you leave ice cubes in there for a long period of time—they decrease in size but never leave behind a puddle of liquid.

So how can we have a picture of liquid water on Mars? The key is salts. Those living in northern climates know that adding salt to ice lowers its melting point. This means that it can be liquid at colder temperatures and your sidewalk won't be icy. Salts also increase the boiling point so that you can have liquid at higher temperatures.

Combine the pressure and salt effects and, according to Nilton Renno and his collaborators you can get liquid brine on Mars. You can see a summary of his work, and some pictures, at this page at the University of Michigan where he does his work.

Of course, the most interesting point of this is that liquid water appears to be the most important ingredient of life. And now we have it on Mars.

A while back I received notice that some images from our site had gone missing. It turned out to be far more severe than that—all of the 2007/8 images had gone missing. Seems some hack-bot script had hijacked my space on the server and in the process, deleted all the images. And me without an archival backup!

I sent out a message to all contributors to ask for resubmission and the first reply I got back, from Ljubomir Djurisic, said that he had done an entire archive of the images up through about mid-June 2008. This recovery saved me a lot work so my thanks go out to Ljubomir.

For the images that came in after that, I have been able to contact those observers and have also recovered those—thanks to them for helping!

I think the archive is good now; the problem is fixed and we should be fine going forward. Just a note to the concerned: the hack was not anything that could affect visitors to the site, that is, no viruses were planted for spreading so you have nothing to fear for uploads during the next apparition.

A week ago last Sunday (28 January) Spirit seems to have had a "mental" hiccup. On its 1800th sol (20 times longer than it was expected to work) it reported that it had received its commands to move but chose not to. It also failed to record its activities for that day into its memory.

While it could be that Spirit is getting old and forgetful (a condition with which I can sympathize) it may be more problematic than that. When it was put through its paces to find the Sun and reorient, it worked, but the Sun was not were it was expected to be. This means the rover was not in its expected orientation. This might mean that some of its attitude sensing hardware (gyroscope and accelerometer) may be damaged.

The rover team is still working on diagnosing the problem. So far, Spirit seems to be following commands, taking pictures, saving info and downloading it. The team will test the attitude hardware and if that checks out, Spirit may resume its journey.

Big news: NASA says there's methane on Mars! Why is this big news? Well, here on Earth most of our atmospheric methane is produced by little microbes in the stomachs of ruminants (e.g. cows and caribou) which makes one wonder if the methane on Mars is also produced by living bacteria.

Back in 2003 three groups reported possible discoveries of methane using the technique of spectroscopy—you break up the light from Mars into hundreds or thousands of colors, then look for "missing" light. The missing colors were absorbed by specific compounds or materials and can be used as a fingerprint to identify them. It's really not quite this simple in practice, but with a lot of diligent effort, it really works quite well.

One group (Mumma et al.) was working from the NASA Infrared Telescope Facility, another was working from the Canda-France-Hawaii Telescope, and the last was using data from the Planetary Fourier Spectrometer on Mars Express. Since then they have all been working hard to confirm their discoveries by gathering more/better data, improving analysis techniques, and working to account for all the known variables in their models. So a few days ago, the fruits of that labor were announced by NASA.

Of course, methane can be produced non-biological means. One such method is that it could have been created during a comet-crash on Mars. One science group calculates that impacts into the Martian dust could have produced enough methane, an efficient greenhouse gas, to have helped keep Mars above freezing for quite some time. Of course, that methane would be long gone today as sunlight rapidly destroys it.

Another idea is that olivine, a mineral discovered to be in one of the methane areas can be chemically altered by water into serpentine to produce methane. This requires relatively warm, liquid water and so, if this is the mechanism, it must happen at depth and during warmer seasons. The produced methane would then seep out of cracks in the rocks and soil, also during warmer seasons when the ice in the cracks is more likely to have sublimated away into the atmosphere.

Either way, biologic or geochemical, this discovery is quite exciting! For more scientific details, you can check out Google-Scholar.