Category: Mars

Try to walk on Mars today, and the planet will simultaneously freeze and suffocate you. Not to mention the minimal air pressure and relentless radiation from space. But billions of years ago, the Red Planet was much warmer and liquid water flowed on its surface. Warm temperatures on Earth are maintained by the carbon cycle, but maybe another greenhouse gas – sulfur dioxide (SO2) – maintained the temperatures on Mars.

This is the hypothesis put forward by Harvard and MIT researchers, published in the December 21st edition of the journal Science.

Over millions of years on Earth, our climate has been controlled by the carbon cycle. Carbon dioxide is released from volcanoes, and then chemical reactions with silicate rocks on the Earth’s surface remove it back out of the atmosphere and turn it into limestone.

There are vast deposits of limestone on Earth; evidence that the carbon cycle has been going on for eons. But planetary geologists haven’t found any limestone on Mars. If the planet was kept warm, the limestone should be there.

Perhaps another greenhouse gas, sulfur dioxide – also released in vast quantities from volcanoes – kept the atmosphere warm. On Earth, sulfur dioxide is removed quickly from the atmosphere, since it’s even more reactive with silicate rocks than carbon dioxide.

“The sulfur dioxide would essentially preempt the role of carbon dioxide in surface weathering reactions,” says Itay Halevy, the first author of the report. “The presence of even a small amount of sulfur dioxide in the atmosphere would contribute to the warmer climate, and also prevent limestone deposits from forming.”

So if this is true, sulfur minerals, and not limestone, should have formed in bodies of water. This may help to explain the surprising discovery the rovers have made that sulfur minerals are an abundant component of Martian soils.

With sulfur dioxide, the Martian oceans would have been much more acidic than Earth’s oceans. There might have been periods on Earth when our atmosphere was similar, and there could be similar periods when sulfur kept us warm too.

The similarities and differences of the two planets still have much to teach scientists.

Original Source: Harvard News Release

Okay, now you can tell your friends and family that Mars is making its closest approach, and not August like that annual hoax email that goes around. This image of Mars, taken by the Hubble Space Telescope, was captured when the planet was only 88 million km (55 million miles) away from Earth. Their closest point occurs on December 18th at 1145 UTC (6:45 p.m. EST).

This close encounter between the Earth and Mars happens every 26 months. That’s because Earth makes more than two orbits for every one Martian trip around the Sun. As the Earth catches up with Mars in orbit, the planet brightens in our skies until it becomes one of the brightest objects we can see.

Since both Earth and Mars have elliptical orbits, the point of their closest approach changes from year to year. Back in 2003, when that closest approach between Earth and Mars actually happened, the two planets were 32 million km closer (20 million miles) than today. (Of course, Mars never looked as large as the Moon in the sky, it was always just a bright red star.)

The image attached to this story was made up of a series of photographs captured by Hubble over the last 36 hours. They were then stitched together on computer to make up this composite photograph.

The large triangular dark shape on Mars is Syrtis Major, and the region on the left is called Sinus Meridani. That’s roughly where NASA’s Opportunity rover is currently rolling across the Martian landscape.

When Hubble took this photograph, the planet was largely free of the dust storms that plagued the Mars rovers earlier this year. Although, you can see clouds near the northern and southern poles.

Original Source: Hubble News Release

Just in case you needed more evidence that yes, there are robots from Earth roving around on Mars, check out this photograph. Okay, so it’s a little blurry, and you wouldn’t actually know what you were looking at unless I told you. That’s NASA’s Spirit rover, photographed by the Mars Reconnaissance Orbiter.

The blue diamond-shaped feature in the image is “Home Plate”; a puzzling region located inside the massive Gusev Crater on Mars. Spirit is a tiny dark grey speck inside Home Plate? See it? No, ah well, we’ll just have to trust the imaging folks over at NASA and the University of Arizona.

This colour image of Spirit was captured on September 27th by the High Resolution Imaging Science Experiment on board NASA’s Mars Reconnaissance Orbiter. During this period it was flying about 270 km (168 miles) above the surface of the planet.

Although you really can’t see too much of Spirit, the image helps planetary geologists put data sent back by Spirit into context.

Spirit is now driving itself to a safe, north-facing slope on the north side of Home Plate. This will position its solar panels towards the Sun, so that it can soak up as much of the Sun’s light as possible during the long Martian winter. This will let the rover continue its science operations.

Original Source: UA News Release

There will never be a better time to ask Santa for a telescope than this Christmas! Over the last few weeks the planet Mars has doubled in brightness… and for every minute that passes… Earth and Mars get about 590 kilometers closer! Closer, that is, until December 18 when our separation will be about 88.5 million kilometers apart.

Like a cosmic present, the Red Planet will reach opposition on December 24 when it will be exactly opposite the Earth from the Sun and visible from dusk til’ dawn. At around twice the size of Luna and over 230 times further away, Mars will never appear as large as the Full Moon, but it will outshine the rest of the stars in the sky for a short time. What a wonderful holiday treat for even a small backyard telescope!

Don’t be disappointed if the view doesn’t look like a Hubble image. The average telescope will reveal Mars’ soft orange globe, dark mottling and a wink of a polar cap with steady seeing. You might even spot the blue-tinged haze of a carbon-dioxide atmosphere. If you view Mars on several different occasions at various times, you’ll soon learn to spot surface markings. Remember to be patient!

The best views come during a moment of steady seeing and too much magnification can harm the view. Some good advice is to wait until Mars is reaching culmination (its highest point) and make sure your telescope has reached outdoor temperature. Begin with the lowest magnification possible and work your way up to what the sky will allow. Don’t just take a peek and walk away! Stay and watch for awhile…

Sketching is a good way to train your eye to see more details and provides you with your own observing record to compare with photographs of features. Try using great on-line interactive tools like this one from Sky & Telescope, Mars: Which Side Is Visible?

SkyWatchers aren’t the only ones taking advantage of the Mars’ approach! In August 2007 NASA launched the Phoenix Lander and its due to reach Mars in May 2008 where it will join Spirit and Opportunity. When you look at Mars, think of what the future might bring! Less than four decades ago, mankind made the monumental achievement of standing on the lunar surface in around three days.

Now missions like the Mars Pathfinder arrive at an even more distant world in seven months. According to NASA, mankind will soon be heading to the Moon “for extended periods of time, astronauts will search for resources and learn how to work safely in a harsh environment — stepping stones to future exploration.” To Mars; “Robotic missions have found evidence of a watery past, suggesting that simple life forms may have developed long ago and may persist beneath the surface today. Human exploration could provide answers to some profound questions.” and Beyond; “As humans and robots work together exploring the moon and Mars, NASA spacecraft will continue to send back scientific data from throughout the solar system, laying the groundwork for potential human journeys.”

Perhaps one day future astronauts will be wishing us a “Very Martian Christmas”!

With a fleet of spacecraft orbiting Mars, and rovers crawling across its surface, there’s a flood of images of the Red Planet. It’s nice to know the scientists working on those missions can take the time to look elsewhere every now and then. So today, let me present to you some images of the Martian moons: Phobos and Deimos.

The two images of the Martian moons were captured by the Compact Reconnaissance Imaging Spectrometer for Mars on board NASA’s Mars Reconnaissance Orbiter. Both images were captured while spacecraft was over Mars’ night side, and the ground below was dark.

In order to reorient away from Mars to view the moons, MRO had to turn off its normal nadir-viewing geometry.

The image of Phobos (on the top) was captured on October 23, and shows features as small as 400 metres (1320 feet) across. The image of Deimos was captured on June 7, and shows features as small as 1.3 km (0.8 miles) across.

Phobos is only 21 km (13 miles) across, and orbits Mars once every 7 days, 39 minutes. Because the moon orbits Mars faster than it rotates, Phobos would appear to travel backwards across the sky from an observer on the ground. This is just an illusion, though. Even though it’s tiny, Phobos orbits so closely that it would appear to be 1/3rd the size of our own moon in the sky.

Deimos is even smaller – 12 km (7.5 miles) – but it orbits more distantly than Phobos. It takes 1 day, 6 hours and 17 minutes to orbit the planet. Deimos isn’t large enough that you could make out any features from the surface of Mars. Instead, it would just look like a bright star in the night sky.

The first ever spacecraft observations of the Martian moons were made by Mariner 9 and the Viking Orbiter spacecraft. They found the moons to have very low reflectivity, and appeared to be similar in structure to carbonaceous chondrite meteorites. This led to the commonly held view that the moons are captured asteroids.

Original Source: MRO News Release

Here’s an interesting image released today captured by NASA’s Mars Reconnaissance Orbiter. It’s of an unnamed crater on Mars in the Terra Cimmeria region that could contain ancient deposits of chloride salts. The region is one of the most geologically interesting on Mars. It’s riddled with impact craters, crisscrossed by dried up river channels, and sculpted by wind. Water probably acted on the region a long time ago, building up the salt deposits.

This region of Mars is of great interest to scientists. Three separate missions have studied the area in great detail: Mars Global Surveyor, Mars Odyssey, and now the Mars Reconnaissance Orbiter. Over the years, they have shown how these small deposits of chloride salts are scattered across the Martian surface.

They’re more widely found in the Noachian (most ancient) regions, and less found in the Hesperian (middle geologic time) terrain. This means that the deposits were probably laid down in the earliest epochs of Martian history, and then later geologic processes resurfaced them.

This image, captured by the HiRISE instrument on NASA’s Mars Reconnaissance Orbiter shows one of these deposits. The photograph reveals an area about 900 metres across, including a partially buried unnamed crater in Terra Cimmeria. The chloride salt deposits in this photograph are the lighter toned colour. The deposits are relatively thin and occur in low lying areas. This one has been heavily eroded, which suggests that it’s very old.

Original Source: HiRISE News Release