Category: Mars

Planetary geologists have a relatively simple method for calculating the age of a planet’s surface: count the number of impact craters in a region. The older the surface, the more craters there will be from meteorites that have struck the planet over the ages. Areas with fewer craters are generally interpreted as younger surfaces where other geological processes such as volcanic activity or plate tectonics, have erased the impact scars. A new analysis of impact cratering using images from the Mars Express has revealed that Mars has undergone at least five violent, global volcanic upheavals, shaping the surface of Mars we see today.

Using the High Resolution Stereo Camera (HRSC) on Mars Express, planetary scientists are learning more about Mars’ past. “We can now determine the ages of large regions and resurfacing events on the planet,” says Gerhard Neukum. Resurfacing occurs when volcanic eruptions spread lava across the planet’s surface. But unlike Earth, where resurfacing happens gradually and slowly, Mars has had a series of violent volcanic periods. This occurred more than 3.8 thousand million years ago. In between these episodes, the planet has been relatively calm.

During these volcanic episodes, eruptions of lava flowed across Mars. The internal heat generated by the volcanic activity also caused water to erupt from the interior, causing wide-scale flash flooding.

Why did Mars behave like this? Geophysical computer-based models suggest that the planet has been trying to establish a system of plate tectonics, as there is on Earth where the crust is broken into slowly moving plates. On Mars, the volcanic episodes represent the planet almost, but not quite, developing plate tectonics.

We recently saw a landslide on Mars. Could we possibly see a volcanic eruption? “The interior of the planet is not cold yet, so this could happen again,” says Neukum.

Original News Source: ESA Press Release

Despite what it might look like, this is not the beach of a lakeside resort here on Earth. It’s what remains of a dried up lake on the surface of Mars, yet another fantastic image brought to us by the cameras on the High Resolution Imaging Science Experiment (HiRISE.) This is a closeup of the largest of the “fans” leftover from the lake in the bottom of Holden Crater, an 87-mile (140-kilometer) wide crater in the bottom of the larger Holden Basin on Mars.

What’s interesting about a dried up lake bed, besides the spectacular image? Well, it’s the perfect place to start a search for life on Mars. A nice, calm lake would be a likely place for life to form. This site is one of the six possible landing sites for the NASA’s Mars Science Laboratory, which launches next year and will try to answer the question of whether life on Mars existed at one time, or continues to thrive there.

In addition to the possiblity that the lake was at one time inhabited by Martian life, the crater is full of rocks and sediment that are of interest to geologists studying the history of Mars. Called “megabreccia”, the floor of the crater contains a mixture of boulders, sediment and clay. Before the impact that formed the crater, sediments were deposited in the bottom of Holden Basin by channels of water running across the basin. Blocks of the surface as large as 50 meters (164 feet) across were thrown up when the crater was made.

“When large craters form, they produce very large blocks of material. We see them on Earth. Popigai Crater in Russia is one example. But we’d never seen them on Mars, and we knew they ought to be there. Now we’ve seen them with HiRISE,” said John Grant of the Smithsonian National Air and Space Museum, who is the first author on a paper about Holden Crater recently published in the journal Geology.

The crater’s history is even more complicated: the rim of the crater was breached by surrounding water, creating a massive flood that stirred up the sediments on the bottom and re-filled the crater. Boulders and debris from the event are strewn over the top of the megabreccia, and are also covered in fine sediment and clay that settled on them from the lake before it dried up. The volume of water in this catastrophic flood would have been larger than that contained within Lake Huron.

Both images used here are in false color to help reveal details. This second image shows the layers produced by the impact and subsequent flooding, most noticeable on the walls in the upper left-hand corner. Mars was likely wetter during its early history, and the flow of water later in its life was probably reserved to catastrophic events such as the breach of Holden crater.

Images like this and more have been really pouring in from HiRISE. To see more, check out their site and our coverage here at UT on this fantastic image of an avalanche in progress on Mars, and this picture of the Earth and Moon together in one beautiful shot.

Source: University of Arizona Press Release

Will humans ever really go to Mars? Let’s face it, the obstacles are quite daunting. Not only are there numerous, difficult, technical issues to overcome, but the political will and perseverance of any one nation to undertake such an arduous task just can’t be counted on. However, one former NASA engineer believes a human mission to Mars is quite doable, and such an event would unify the world as never before. But Jim McLane’s proposal includes a couple of major caveats: the trip to Mars should be one-way, and have a crew of only one person.

McLane worked at NASA for 21 years before leaving in 2007 to work for a private engineering firm. Being able to look from afar at NASA’s activities has given him a new perspective, he says.

But McLane was still at NASA when he originally had an idea for a one-way, one-person mission to Mars. He calls his proposal the “Spirit of the Lone Eagle,” in deference to Charles Lindbergh’s solo flight from New York to Paris in 1927.

McLane’s idea came from his acquaintance with a Russian cosmonaut. “I noticed the cosmonaut seemed to be a slightly different type of person than the American astronaut,” McLane said. “Cosmonauts are primarily pilots, and like test pilots, they are very focused on getting the job done. The current American astronauts are picked for things such as their speaking ability and social skills, and most of them have advanced degrees. But the cosmonaut struck me as an adventurous, get-things-done-type person, like our original astronauts back in the 1960’s.”

A return to the “get it done” attitude of the 1960’s and a goal of a manned landing within a short time frame, like Apollo, is the only way we’ll get to Mars, McLane believes. Additionally, a no-return, solo mission solves many of the problems currently facing a round-trip, multiple person crew.

“When we eliminate the need to launch off Mars, we remove the mission’s most daunting obstacle,” said McLane. And because of a small crew size, the spacecraft could be smaller and the need for consumables and supplies would be decreased, making the mission cheaper and less complicated.

While some might classify this as a suicide mission, McLane feels the concept is completely logical.

“There would be tremendous risk, yes,” said McLane, “but I don’t think that’s guaranteed any more than you would say climbing a mountain alone is a suicide mission. People do dangerous things all the time, and this would be something really unique, to go to Mars. I don’t think there would be any shortage of people willing to volunteer for the mission. Lindbergh was someone who was willing to risk everything because it was worth it. I don’t think it will be hard to find another Lindbergh to go to Mars. That will be the easiest part of this whole program.”

And like Apollo, such a mission would stimulate new technology and reinvigorate science. McLane feels a mission to Mars should be international in scope, encompassing contributions from multiple nations to represent a milestone for the whole human race.

“I think people have forgotten how exciting the Apollo program was, and this would bring that excitement back,” he said. “And it wasn’t just here in the US; the whole world was excited. This enthusiasm would be the greatest effect of a program that places a man on Mars, over and above anything else, whether it makes jobs, or stimulates the economy, or creates technology spinoffs. We’re all humans and the idea of sending one of our kind on a trip like that would be a wonderful adventure for the entire world. The whole world would get behind it.”

And the whole world would be watching, said McLane, so it wouldn’t be as if the lone astronaut would be completely by himself. “You would have constant communication,” he said. “The astronauts on the International Space Station have an army of people on earth keeping track of what they are doing. They really have no peace. Somebody is constantly planning and monitoring their activities. I don’t think being lonely will be much of a problem on a mission to Mars.”

Of course McLane’s hope is the solo astronaut would be joined by others shortly in the future. Orbital mechanics provides a desirable launch window from Earth to Mars every 26 months. “This person wouldn’t be there by himself for very long. It’s just returning home that would be impossible,” he said. Another option McLane has offered is a one-man and one-woman crew, possibly creating an Adam and Eve-type situation.

Unmanned landers would carry living accommodations, supplies and communication equipment to Mars’ surface before the human mission would even launch. The best location on Mars would be a low, sheltered area, perhaps at the bottom of a canyon, which would provide protection from radiation and weather, as well as the highest possible atmospheric pressure.

While technical issues abound for even the simplest human mission to Mars, McLane says technical issues didn’t deter the Apollo program, and they shouldn’t deter a mission to another planet.

“I can remember during the early days of the Apollo program, there were even many more technical issues than we face today in going to Mars,” said McLane. “People don’t realize that, or have forgotten that fact. Several things were tremendous unknowns back then, any one of which could have been a showstopper for a human moon landing.”

McLane said the early designers of the Apollo spacecraft gambled that in 3 or 4 years, high powered transistors and small guidance computers would be developed. That was the only way the spacecraft would be lightweight enough to land on the moon. “It was almost science fiction, but someone thought it could be done in just a few years, and sure enough the technology was perfected in time to make the mission possible,” he said.

Image: Jim McLane during his career at NASA.

While Apollo 11 astronaut Buzz Aldrin and noted author and physicist Paul Davies have also advocated a one-way trip to Mars, in our risk-averse society most people look askance at such an idea.

Even though explorers in the past traveled, for example, to the south or north pole, knowing they might never return, and thousands of immigrants moved to the US in the 18- and 1900’s, knowing they would never see their homeland again, the human psyche has seemingly changed enough that a one-way ticket off the planet is not acceptable. According to psychologist Molly Dooley from Springfield, IL, it might take a major crisis on Earth for humans to seriously consider such a mission. “Usually it’s the disenfranchised that are willing to take those kinds of risks,” she said. “When our present situation no longer works for us, we become more willing to take risks. The difference between the folks who are interested and those who aren’t is their attachment to their current situation.”

McLane says the main reason NASA hasn’t been able to focus on a human mission to Mars is simple: NASA doesn’t get nearly enough money. “This has been the case for many years,” he said. “They didn’t get enough money to fix problems with the shuttle, and they’ve always been chronically short of money. How we fund NASA is a big handicap, since every year, NASA has to go begging to Congress for funds and justify their budget. The Chinese space program, on the other hand, has an advantage in that they budget their projects in five-year increments. If we really want to go somewhere, we’ll have to change how NASA gets its money.”

But McLane thinks NASA is at fault for not even considering a one-way mission to Mars. “For over forty years they’ve studied all sorts of options, but haven’t admitted to ever looking at a one-way mission to Mars,” he said. “We shouldn’t be stuck on this rock forever. I believe it’s in our human nature to try to go somewhere else, and we’ve almost worn this world out. I think now is the time to reach out and go somewhere else to start with a clean slate. There is no reason not to try.”

Magnificent images of avalanches of ice and rock in the northern polar regions of Mars have been captured by NASA Mars Reconnaissance Orbiter’s (MRO) High Resolution Imaging Science Experiment (HiRISE). These images are not of landslides that have happened in the past, they are actual Mars avalanches happening at the moment of observation. This rare event will be of tremendous value to Mars scientists currently analysing the effects of seasons on the landscape and will provide information on the geological activity of the planet…

This event occurred along a scarp (a distinct cliff, with a steep runoff) around the North Polar Region where surface ice can be found in large quantities. The HiRISE instrument was being used to assess seasonal changes around the North Pole when four areas of activity were seen along the scarp. HiRISE was witness to something more familiar on Earth than on Mars: avalanches.

This particular scarp is a high cliff over 700 m (2300 ft) tall and slopes at over 60 degrees. A mixture of ice, rock and dust can be seen, frozen in time, as it is plummeting down the slope, ejecting a plume of dust as the debris begins to settle on the gentle slope at the bottom of the cliff. The ejected cloud is approximately 180 meters across and extends about 190 meters beyond the base of the cliff. It is worth noting that the clouds are large 3D structures reaching into the Martian atmosphere and not 2D patterns on the surface (shadows from the plume can be seen to the lower left of the clouds of dust).

The Martian landscape does not change very much over millions of years. Unlike the Earth, Mars does not have a thick, eroding atmosphere blasting away at the surface features. The lack of water also reduces these erosion effects. Mars also has very little geological activity as core reactions are thought to have slowed or even stopped – there is therefore very little tectonic movement, no major earthquakes and no evidence for present volcanic activity.

So what caused these avalanches? HiRISE scientists have some ideas:

• Disappearance of carbon dioxide frost, dislodging rocks.
• Expansion and contraction of ice due to seasonal temperature differences.
• Small Mars-quakes.
• A nearby meteorite impact.
• Vibrations from other avalanches causing other avalanches along the scarp

It seems most likely that the trigger may be down to seasonal changes. As the North Polar Region heats up (progressing toward summer), solid carbon dioxide (“dry ice”) may be subliming, weakening rocks around the edge of the cliff. The same could be said for the thermal expansion and contraction of water ice as the seasonal air temperature becomes warmer or cooler.

Whatever the cause, we are very lucky to have captured this event, the science collected from these observations will be critical to understanding how the Martian landscape can change very rapidly. The HiRISE instrument continues to return the most magnificently detailed images of the Red Planets surface, these observations of Mars avalanches will certainly go into the Mars Reconnaissance Orbiter’s Hall of Fame…

Source: HiRISE Project Site

With three orbiters and two rovers currently at Mars, there are always interesting images coming back from the Red Planet. Here’s a round-up of the latest images from the five different spacecraft. First up is a fascinating image from the Mars Odyssey spacecraft of dust devil tracks. It’s amazing just how many tracks there are in just this one image. Martian dust devils can be up to fifty times as wide and ten times as high as dust devils seen on Earth. This image was taken by Odyssey’s Thermal Emission Imaging System (THEMIS), and shows an area in the south polar region, just east of Daly Crater. Resolution is about 17 meters per pixel. Original Image link.

NASA’s Mars Exploration Rover Spirit has this view northward from the position at the north edge of the “Home Plate” plateau where the rover will spend its third Martian winter. And no, that’s not a pool of water in the image. It’s just rippled sand in the “El Dorado” sand dune field, and the image is shown in false color.

Husband Hill is on the horizon. Spirit used its panoramic camera (Pancam) to capture this image during the rover’s 1,448th Martian day, on January 29, 2008.
Original image link.

This view from the Opportunity rover shows a close-up of bedrock from the inside of Victoria Crater, where the rover is currently studying a stratigraphic layer of rocks. This area is informally named “Lyell,” which is the lowermost of three layers the rover has examined at a bright band around the inside of the Crater.

Opportunity used its panoramic camera (Pancam) to capture this image with low-sun angle at a local solar time of 3:21 p.m. during the rover’s 1,433rd Martian day, on February 4, 2008. This image, too, is in false color to highlight the ripples and bands in the bedrock.
Original Image link.

ESA’s Mars Express took snapshots of Candor Chasma, a valley in the northern part of Mar’s huge canyon, Valles Marineris, as it was in orbit above the region on 6 July 2006.

The High Resolution Stereo Camera on the orbiter obtained the data,with a ground resolution of approximately 20 m/pixel. Candor Chasma lies at approximately 6° south and 290° east.
Original Image link.

This image taken by the Mars Reconnaissance Orbiter (MRO) shows a volcanic vent. A volcanic vent is an opening in the crust of a planet that emits lava (molten rock) and volcanic gases. The rough texture of the plains surrounding the vent iindicates that it is lava.

There is a large number of snake-like features emanating from the vent. The parallel lines that outline the features are levees, which mark the edges of channels that carried molten lava. As lava flows, it moves slowest at its edges and bottom because the lava sticks to the non-flowing rocks, and as the lava slows, it cools off and hardens.

Levees form when the sides harden but the center of the flow keeps moving. As the eruption episode ends, and the lava drains, the center is left lower than the sides producing these high-standing structures. Of course, these lava flows are very, very old.
Original Image page.

The High Resolution Imaging Science Experiment (HiRISE) on board NASA’s Mars Reconnaissance Orbiter (MRO) observed what appeared to be fresh gullies formed by a rapid release of water on the Martian surface in 2006. However, new computer models simulating the creation of gullies on the surface of Mars suggest that they are in fact created by the flow of dry debris (i.e. landslides) and not by the flow of water. A blow for the microbial life hunters and a huge blow for mission planners looking for easy sources of water for manned missions…

The MRO isn’t the only orbiter to view apparent gullies forged by spurts of water. The Mars Orbiter Camera (MOC) onboard NASA’s Mars Global Surveyor (MGS) also made news in 2006 when scanning the cratered regions of Terra Sirenum and Centauri Montes. Images taken several years apart revealed some changes in the most recent pictures, highlighting what looked like outflow channels from surges of liquid water (pictured below). What made this especially exciting was that this was possible evidence for the existence of liquid water flowing on Mars within the past few years (albeit very quickly).

New work by scientists at the University of Arizona appears to conflict with these observations. In an attempt to demonstrate the characteristics of water flowing in Martian conditions, Associate Professor Jon D. Pelletier (Geophysics) and colleagues used topological data from the HiRISE instrument (the most advanced imaging system currently orbiting Mars) and modelled the flow of water down a slope. What the simulation showed was a surprise; the researchers went into the project thinking they were going to prove that the gullies were formed by water. Instead, they had shown that the shapes and characteristics of the observed gullies most resembled that of the modelled gullies shaped by dry debris tumbling down a slope.

“The dry granular case was the winner. I was surprised. I started off thinking we were going to prove it’s liquid water.” – Jon D. Pelletier

Looking at the comparison between the two cases (water and dry debris flow) and the HiRISE observations, it is very easy to see the striking resemblance between dry debris flow and what is actually observed. The water simulation appears to be more diffuse, lacking the characteristic “fingers” reaching down the slope.

On hearing the news in 2006 that there was a possibility of liquid water flowing on the Martian surface, biologists hoped that a new tool had been found to pinpoint where sub-surface deposits of liquid water may be stored. This will have provided future missions with a location to hunt for life in the most likely place, near fresh gullies, near a source of water. Unfortunately it seems that these gullies are in fact shaped by small landslides, not by surges of water from a sub-surface reservoir.

Research to be published in the March issue of Geology, entitled: “Recent bright gully deposits on Mars: wet or dry flow?“.

Source: University of Arizona News