Tag Archives: climate

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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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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Mars’ ancient climate had a “wet-pass” filter

Volcanic eruptions — and the rocks they produce — dominate the surface of the Red Planet. Mars also shows evidence for activity by liquid water — sediments, channels, and valley networks — through much of its history. While volcanos can … Continue reading

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Mars’ explosive childhood

Mars is widely understood to be a volcanic planet — its surface shows abundant evidence of volcanic activity, both ancient and more recent. Spacecraft detect lava flows in many locations, and spectroscopic evidence of volcanic rocks lies almost everywhere. The … Continue reading

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Hesperian lava floods thicker than previously thought

A study examining layered “megablocks” of lava in the central parts of Mars craters concludes that flood lavas in the Hesperian epoch were at least 23 percent thicker than previously known. The research says this shows there has been more … Continue reading

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Hidden valley at the north pole

The north polar cap of Mars has a wide, deep trough called Chasma Boreale that slices into the polar cap for 560 kilometers (350 miles). The floor of the chasma exposes a layer of sand and dust cemented with water … Continue reading

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Home Plate’s volcanic bomb landed with a splat

One of the unusual features that Mars Exploration Rover Spirit discovered at Home Plate, a former hydrothermal vent in the Columbia Hills, was a “bomb sag,” complete with its partially embedded volcanic bomb. To geologists, volcanic bombs are rocks or … Continue reading

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