Author Archives: rburnham

Dry ice slabs carve linear grooves down Mars dunes

The “megadune” in Russell Crater features linear grooves or gullies a few meters wide, a meter or two deep, and roughly a kilometer or two long. The origin of these gullies and similar ones in other high-latitude craters has been … Continue reading

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Was nitrogen in the early Mars atmosphere a key to ancient habitability?

Scientists have long suspected that ancient Mars had a thicker atmosphere and temperatures warmer and far more habitable than at present. But modelers have difficulties making the numbers come out right, even when they assume a much thicker carbon dioxide/water … Continue reading

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Well-rounded pebbles in Gale Crater’s rocks point to longtime stream flow

Mars Science Laboratory rover Curiosity landed in Gale Crater at a feature called Bradbury Rise, which lies near the far end of the Peace Vallis alluvial fan. The fan is a broad, flat deposit of sand, gravel, and pebbles washed … Continue reading

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Aeolis Serpens, Mars’ longest sinuous ridge, is an ancient riverbed

A linear ridge that winds for more than 200 kilometers (120 miles) through part of South Australia was a river channel roughly 10 million years ago. After the paleoriver stopped flowing, silica-rich groundwater seeped into the riverbed, cementing its sediments. … Continue reading

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Most deltas on Mars created by short, catastrophic floods

Rivers that run into lakes and other standing bodies of water drop sediment where the flow slackens as it enters the body of water. Over time, the accumulating material builds a delta — a wedge of sediment whose form can … Continue reading

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Are brines actually needed to make recurring slope lineae flow?

Recurring slope lineae (RSL) are finger-like dark lines on steep slopes that appear and grow longer during the warmest time of year, then fade and disappear over winter. They repeat the following Mars year in the same places. While scientists … Continue reading

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‘Faint young Sun paradox’ a problem for Mars (and Earth, too)

Astronomers say that billions of years ago when the Sun was young, it shone with only 70 percent its current brightness, notes Robert Craddock (Smithsonian Institution). If that were true of today’s Sun, he explains, Earth’s surface would freeze over, … Continue reading

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Gale’s winds sculpted the Mt. Sharp mound as they built it

The major reason for sending the Mars Science Laboratory rover Curiosity to Gale Crater is the five-kilometer (three-mile) high layered mound, dubbed Mt. Sharp, that looms at the crater’s center. The lowest layers have been altered by water and perhaps … Continue reading

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Dust drifts: new windblown feature on Mars?

Mars has ample loose material blowing around on its surface, a fact which has been known and studied for decades and more. However scientists have paid little attention to sedimentary deposits of dust. New work using detailed images from the … Continue reading

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Icy jets erupt from north polar dunes in spring

Jets of gas erupting in the springtime from beneath slabs of carbon dioxide ice at the Martian south pole was a dramatic finding in 2006. It explained the mysterious “spiders” which came and went each year. Now the same mechanism … Continue reading

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