Posts Tagged ‘volcanoes’

Ancient Volcanic Explosions Shed Light On Mercury’s Origins

Mercury1.preview_smMercury was long thought to be lacking volatile compounds that cause explosive volcanism. That view started to change when the MESSENGER spacecraft returned pictures of pyroclastic deposits — the telltale signature of volcanic explosions. Now more detailed data from MESSENGER shows that volcanoes exploded on Mercury for a substantial portion of the planet’s history. The findings suggest Mercury not only had volatiles but held on to them for longer than scientists had expected.

The surface of Mercury crackled with volcanic explosions for extended periods of the planet’s history, according to a new analysis led by researchers at Brown University. The findings are surprising considering Mercury wasn’t supposed to have explosive volcanism in the first place, and they could have implications for understanding how Mercury formed.

Mercury was long thought to be bone dry when it comes to volatiles, and without volatiles there can’t be explosive volcanism. But that view started to change in 2008, after NASA’s MESSENGER spacecraft made its first flybys of Mercury. Those glimpses of the surface revealed deposits of pyroclastic ash — the telltale signs of volcanic explosions — peppering the planet’s surface. It was a clue that at some point in its history Mercury’s interior wasn’t as bereft of volatiles as had been assumed.

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New Insights Concerning The Early Bombardment History On Mercury

The surface of Mercury is rather different from those of well-known rocky bodies like the Moon and Mars. Early images from the Mariner 10 spacecraft unveiled a planet covered by smooth plains and cratered plains of unclear origin. A team led by Dr. Simone Marchi, a Fellow of the NASA Lunar Science Institute located at the Southwest Research Institute (SwRI) Boulder, Colo., office, collaborating with the MESSENGER team, including Dr. Clark Chapman of the SwRI Planetary Science Directorate, studied the surface to better understand if the plains were formed by volcanic flows or composed of material ejected from the planet’s giant impact basins.

Recent images from NASA’s MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft provided new insights showing that at least the younger plains resulted from vigorous volcanic activity. Yet scientists were unable to establish limits on how far into the past this volcanic activity may have occurred, or how much of the planet’s surface may have been resurfaced by very old volcanic plains.

“By comparing the measured craters to the number and spatial distribution of large impact basins on Mercury, we found that they started to accumulate at about the same time, suggesting that the resetting of Mercury’s surface was global and likely due to volcanism,” said lead author Dr. Simone Marchi, who has a joint appointment between two of NASA’s Lunar Science Institutes, one at the SwRI in Boulder and another at the Lunar and Planetary Institute in Houston.

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Monitoring Io’s Insane Volcanic Activity From The Comfort Of Earth

October 17, 2012 Leave a comment

Watching active volcanic eruptions should definitely be done from a distance, but a group of California researchers has figured out how to do it from the comfort of home. Using an ingenious combination of Earth-based telescopic surveys and archival data, they have gathered nearly 40 distinct snapshots of effusive volcanic eruptions and high temperature outbursts on Jupiter’s tiny moon, Io, showing details as small as 100 km (60 miles) on the moon’s surface.

Io, the innermost moon of Jupiter, is an insanely active volcanic wonderland. Although the most detailed observations have come from spacecraft, the Galileo Jupiter orbiter mission ended in 2003 and no future mission capable of studying Io is planned until, at the earliest, 2030. However, there will be no large gap in the monitoring of Io’s volcanoes, thanks to the efforts of teams like that led by Franck Marchis, a researcher at the Carl Sagan Center of the SETI Institute. Marchis will present results from ground-based telescopic monitoring of volcanic activity on Io over the past decade at the 2012 DPS Meeting in Reno, Nevada.

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Astronomers Find Ice and Possibly Methane on Snow White, a Distant Dwarf Planet

August 22, 2011 Leave a comment

An artist's conception of 2007 OR10, nicknamed Snow White. Astronomers suspect that its rosy color is due to the presence of irradiated methane. Credit: NASA

An artist's conception of 2007 OR10, nicknamed Snow White. Astronomers suspect that its rosy color is due to the presence of irradiated methane. Credit: NASA

Astronomers at the California Institute of Technology (Caltech) have discovered that the dwarf planet 2007 OR10—nicknamed Snow White—is an icy world, with about half its surface covered in water ice that once flowed from ancient, slush-spewing volcanoes. The new findings also suggest that the red-tinged dwarf planet may be covered in a thin layer of methane, the remnants of an atmosphere that’s slowly being lost into space.

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