August seems to be the silly season for Mars as inboxes fill with a perennial hoax e-mail that arrives at about this time every year. The mail tells readers that Mars is due to an incredibly close approach, so close in fact that it will appear as it the Earth has two moons in the sky. The story seems to have originated from the genuine close approach of August 2003, when the planet came within 35 million miles of us. By no stretch of the imagination did it appear as large as our own moon, but it was some 6 times large than normal and 85 times brighter. From this has sprung the hoax mail, which somehow re-emerges every year no matter where Mars is in the firmament. Alas, to get anything like a repeat of the 2003 show, you’ll have to wait for 2018, though it won’t actually be until 2287 that we’ll get an approach as close again.
The Opportunity and Spirit rovers are facing the most serious threat yet encountered on their 3 year sojourns on Mars, with a massive dust storm reducing power levels to their lowest ever levels. Opportunity is the worst effected of the two rovers, with direct sunlight levels to its solar panels reduced by up to 99% in the last few days. Mission scientists have been scaling back science operations for both Rovers, switching off instruments and basically hunkering the machines down in the hope that they can survive. The biggest problem is that they can't simply switch the rovers off and on again after the storm clears. A minimum amount of power is required to run heaters that keep vital core electronics from becoming too cold and Opportunity is coming perilously close to the point where it will not be able to cope. Power levels dipped on Wednesday 18th to an unprecedented 128 watt hours, prompting scientists to take the extraordinary action of suspending some of the regular communication sessions with the Rover, a contingency that has never been enacted before.
With an eye to the eventual greening of Mars, Scientists in Mexico are examining Pine trees living on the side of a volcano to see how they cope with the adverse conditions. The snow-capped Pico de Orizaba is not only a dormant volcano but also Mexico's tallest mountain, so the Trees that cling to the side are a hardy breed. Learning how they survive may give clues as to how to one day cultivate plants on Mars, but first we'll need to warm the planet up. Scientist Rafael Navarro-Gonzalez of Mexico City's UNAM University thinks the idea is not necessarily the stuff of science fiction. Global warming here on Earth gives a clue to the process required. If we can introduce highly insulating gases like methane or nitrous oxide in sufficient volume, we could heat Mars. If we can raise the temperature to 41 degrees Fahrenheit from the present minus 67 F, this would match temperatures where trees grow at 13,780 feet on Pico de Orizaba. NASA scientist Chris McKay believes we might see Trees on Mars within 100 years, and sees them as a vital component of any terraforming effort, since Trees are the major "engines of the biosphere."
Fears that a growing dust storm on Mars will deplete power to the Opportunity rover have caused mission planners to delay by a few days the descent into Victoria crater. Opportunity has been surveying the edge of the crater for months, looking for a safe place to begin the perilous descent, but with dust cutting nearly half the available power to the rover, (from 765 watt-hours to 402 watt-hours per day) the decision has been taken to keep the rover in sleep mode as much as possible, with a tentative date of July 13th pencilled in for a full resumption of the mission. The storm has been growing since June, and while mission scientists remain confident that it will abate and be no threat to Opportunity and Spirit, there is some concern that the storm may go global. Such storms are not uncommon, seeming to follow a rough pattern of occurring every 6 years. The last global storm was in 2001, so the planet is due one.
An ancient Mars of rolling oceans is an image pregnant with implications and one that has gained a lot of currency amongst researchers in recent years, but it is good to be occasionally reminded that this is just a theory, and there are plenty of other ways of interpreting the evidence. New Scientist magazine is reporting this week that results from Mars Express cast some doubt on the idea that Mars was once a very wet environment, because it appears to have lacked the necessary carbon-dioxide-rich atmosphere to make this possible. Since the sunlight reaching Mars is 25% less than that on Earth, a very effective greenhouse effect powered by large concentrations of CO2 would have been needed to generate a warm thick atmosphere, 80% more than is experienced on Earth. Analysis of clays, or phyllosilicates, found on the planet by the OMEGA spectrometer on Mars Express seems to indicate that the presence of these clays rules out a large amount of CO2 in the atmosphere since this would have prohibited their formation. Methane, which can also act as a greenhouse gas has been proposed as an alternative driver of a greenhouse effect, but Methane in any significant volume would need an extremely active biosphere, and while it is nice to imagination a tropical Mars in the past, this does not seem very likely. Intriguingly, another alternative has it that large meteor impacts may have caused very brief flurries of wet activity on Mars, in the order of a few thousand years at a time. The question then arises, would a few thousand years of rain (even repeated multiple times) have been sufficient to carve out the river valley like features seen on Mars. Read the article at New Scientist.