Science! By Graham Templeton Nov. 16, 2013 11:05 am
When it comes to Mars, NASA is mostly interested in history. Of course the agency cares about the current state of the Red Planet, about its suitability for colonization and even terraforming, about its hidden caches of useful or precious elements. Still, with Curiosity providing an ever-more-pessimistic view of the chances of modern life on Mars, NASA is turning its sights on the past. Curiosity is blithely blasting at rock samples to try to determine some basic facts about the planet’s geological past, but more specialized historians will be needed to continue the search. Last week saw the launch of the latest such historian, the Mars Atmosphere and Volatile Evolution mission, or MAVEN for short.
When it arrives at the Red Planet late next September, MAVEN will begin to ask why Mars is the way it is. We have strong evidence suggesting that the planet was once covered in liquid water, where none can be found today. It’s probable that the planet was once hospitable to life, where today its thin atmosphere seems ill-suited to an organism’s uses.
Up to about 4 billion years ago, it seems that Mars was a relatively Earth-like place, and a credible starting point for life. So, what happened? MAVEN will set up in orbit around Mars in an attempt to answer that very question.
The video below features an artistic rendering of Mars as it might have existed four billion years ago. Today we can still see dry riverbeds and the effects of flowing water, so seemingly fanciful ideas like the a lake on Mars aren’t quite as far-fetched as they might at first appear.
In the universe, there are some constants that seem to be at least broadly reliable. One of these is the idea of standard isotopic ratios, that different versions of a particular element have properties that make them more or less prevalent in the environment. With no confounding factors, for instance, we should see about 5 times more argon-36 than argon-38; if scientists observe a different ratio than that, they immediately begin looking for a pressure that could push argon away from its natural equilibrium. In the case of Mars, which has an extremely non-standard argon ratio, the most probable explanation is a rapid loss of atmosphere.
One of MAVEN’s components receiving work leading up to its launch late last week.
If some event could start a rapid evacuation of the Martian atmosphere — the two prevailing theories are an unimaginably powerful blast of solar wind and an unimaginably huge planetary impact — then the lighter isotope (the argon-36) would be carried away more quickly than its heavier cousin, thus changing the ratio between the two. Further investigation by explorers like Phoenix and Curiosity confirm the idea that Mars underwent a major ecological shift around that same projected time, but until MAVEN reaches Mars there are few ways to investigate the issue any further.
From its place in orbit, MAVEN will look at the upper atmosphere of the Red Planet to view how it interacts with radiation from the Sun. If Mars did indeed lose its atmosphere due to a blast of solar wind, it would have been because the strong charged particles stripped away the planet’s intrinsic magnetic field and disrupted its ability to hold on to a natural atmosphere. NASA should gain some insight into this hypothesis by watching modern interactions between small gusts of solar wind and the now-thin upper atmosphere.
MAVEN is an orbital accompaniment to Curiosity’s land-based investigations. While NASA’s newest land explorer can dig out samples of rock to be blasted, its talents at surveying the atmosphere are limited. With its high vantage point and ability to look through kilometers of the Martian atmosphere, MAVEN can see what the rovers can not: the gaseous evidence that might just be the key to figuring out why our neighbor planet is a cold, unliving desert.
Now read: Curiosity proves that bits of Mars fall to Earth as meteorites
More...
When it arrives at the Red Planet late next September, MAVEN will begin to ask why Mars is the way it is. We have strong evidence suggesting that the planet was once covered in liquid water, where none can be found today. It’s probable that the planet was once hospitable to life, where today its thin atmosphere seems ill-suited to an organism’s uses.
Up to about 4 billion years ago, it seems that Mars was a relatively Earth-like place, and a credible starting point for life. So, what happened? MAVEN will set up in orbit around Mars in an attempt to answer that very question.
The video below features an artistic rendering of Mars as it might have existed four billion years ago. Today we can still see dry riverbeds and the effects of flowing water, so seemingly fanciful ideas like the a lake on Mars aren’t quite as far-fetched as they might at first appear.
In the universe, there are some constants that seem to be at least broadly reliable. One of these is the idea of standard isotopic ratios, that different versions of a particular element have properties that make them more or less prevalent in the environment. With no confounding factors, for instance, we should see about 5 times more argon-36 than argon-38; if scientists observe a different ratio than that, they immediately begin looking for a pressure that could push argon away from its natural equilibrium. In the case of Mars, which has an extremely non-standard argon ratio, the most probable explanation is a rapid loss of atmosphere.
One of MAVEN’s components receiving work leading up to its launch late last week.If some event could start a rapid evacuation of the Martian atmosphere — the two prevailing theories are an unimaginably powerful blast of solar wind and an unimaginably huge planetary impact — then the lighter isotope (the argon-36) would be carried away more quickly than its heavier cousin, thus changing the ratio between the two. Further investigation by explorers like Phoenix and Curiosity confirm the idea that Mars underwent a major ecological shift around that same projected time, but until MAVEN reaches Mars there are few ways to investigate the issue any further.
From its place in orbit, MAVEN will look at the upper atmosphere of the Red Planet to view how it interacts with radiation from the Sun. If Mars did indeed lose its atmosphere due to a blast of solar wind, it would have been because the strong charged particles stripped away the planet’s intrinsic magnetic field and disrupted its ability to hold on to a natural atmosphere. NASA should gain some insight into this hypothesis by watching modern interactions between small gusts of solar wind and the now-thin upper atmosphere.
MAVEN is an orbital accompaniment to Curiosity’s land-based investigations. While NASA’s newest land explorer can dig out samples of rock to be blasted, its talents at surveying the atmosphere are limited. With its high vantage point and ability to look through kilometers of the Martian atmosphere, MAVEN can see what the rovers can not: the gaseous evidence that might just be the key to figuring out why our neighbor planet is a cold, unliving desert.
Now read: Curiosity proves that bits of Mars fall to Earth as meteorites
More...
