When the Messenger spacecraft swooped low past the planet Mercury on October 6 2008, it gathered up a wealth of data that will have planetary scientists puzzling for years. As researchers sort through findings regarding Mercury’s volcanic past, meteor impacts, and the effect of the solar wind on the innermost planet’s magnetosphere, one broad conclusion stands out: Mercury isn’t just a boring chunk of rock. Marilyn Lindstrom, a NASA program scientist, said the Messenger findings show that Mercury is “just an amazingly dynamic planet, both in the past and in the present” [Baltimore Sun].
Superficially, Mercury looks a lot like the moon: small, grayish-brown and pockmarked with craters. Some scientists assumed that Mercury’s surface formed the same way the moon’s did, with lighter rocks rising to the surface of a magma ocean and congealing into a brittle crust early on. But the new observations reveal that 40 percent of the surface was formed by volcanoes. “Up until before Messenger’s arrival, we weren’t even sure that volcanism existed on Mercury” [Wired], says researcher Brett Denevi. The presence of titanium oxide also suggests that the planet was hot enough in its first 100 million years to be covered in magma oceans.
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About 2.7 billion years ago, the primordial seas already hosted the first photosynthetic microbes, the blue-green algae that took in carbon dioxide and released oxygen into the air. But they were outnumbered by methane-producing bacteria called methanogens [that] thrived in nickel-rich seas. The high amounts of methane that this early life pumped into the environment prevented oxygen accumulation in the atmosphere because the methane reacted with any oxygen, creating carbon dioxide and water [Science News], according to one theory. Now, a group of researchers say they’ve found the trigger that allowed oxygen to build up, and therefore allowed for a profusion of oxygen-breathing life.
The secret was the concentrations of the metal nickel, according to the new study, published in Nature. The scientists found that by analysing a type of sedimentary rock known as banded-iron formations they could monitor levels of nickel in the oceans of the early Earth dating as far back as 3.8 billion years ago. They found there was a marked fall in nickel between 2.7 billion and 2.5 billion years ago [The Independent]. That stretch of time correlates with what researchers call the Great Oxidation Event, when oxygen began to take hold in the atmosphere.
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Saturn’s moon Titan is already an object of fascination to astronomers: The moon has seasonal weather patterns, a thick atmosphere, and lakes of liquid methane on its surface, and some scientists think it’s one of the likeliest spots to find extraterrestrial life in our solar system. Now, researchers have found new evidence that the moon has cryovolcanoes, which, in the cold of the outer Solar System, would spew a slurry of ice and liquid hydrocarbons, instead of lava. “It’s as if it’s a sort of constant bubbling cauldron that occasionally explodes big time,” says Robert Nelson, a Cassini team scientist [Nature News].
The still-controversial theory regards an area of Titan called Hotei Arcus, which appears to fluctuate in brightness on timescales of several months…. The cryovolcanism idea was bolstered in 2008, when observations of Hotei Arcus by a radar instrument aboard NASA’s Cassini probe revealed structures that resembled lava flows [New Scientist]. The new findings, discussed at this week’s Lunar and Planetary Science Conference, are based on radar images taken by Cassini on recent flybys of the moon (radar is required to penetrate Titan’s thick methane atmosphere). Overlapping images were used to create a topographical map of Hotei Arcus; the map shows several lobe-like formations, more than 300 feet high, which researchers say resemble the oozing of a viscous, lava-like material.
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The Alaskan volcano Mount Redoubt erupted last night with four large explosions, sending an plume of ash 50,000 feet into the air, the Alaska Volcano Observatory reported. The volcano lies only 100 miles southwest of Anchorage, Alaska’s largest city, but geologists say that current wind patterns are likely to carry the ash cloud to the north. “It looks like (Anchorage) might dodge the bullet,” Alaska Volcano Observatory geophysicist Peter Cervelli said [Anchorage Daily News]. Mudflows are also possible on nearby rivers.
The 10,200-foot Mount Redoubt last erupted during a four-month period from 1989-90…. Alaska volcanos typically explode and shoot ash upward, sometimes to 50,000 feet, high into the jet stream. An eruption of Redoubt on Dec. 15, 1989, sent ash 150 miles away into the path of a KLM jet, stopping its engines. The jet dropped more than two miles before the crew was able to restart engines and land safely at Anchorage [Fox News]. This time, Anchorage airport officials say they’ve canceled some flights, but have no immediate plans to close the airport.
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Astrobiologists searching for the ultimate prize on Mars–extraterrestrial life–should send a robot scout straight to the mighty Martian volcano Olympus Mons, geologists say in a new study. New research shows that liquid water probably once sloshed beneath the 15-mile-high volcano. It may still be there, and it may be nice and warm, thanks to volcanic heat. “Olympus Mons is a favored place to find ongoing life on Mars,” said the study’s lead author, geophysicist Patrick McGovern…. “An environment that’s warm and wet, and protected from adverse surface conditions, is a great place to start looking” [Wired].
Rising three times higher than Mount Everest, Olympus Mons was active at least 40 million years ago, and perhaps more recently [ABC Science]. For the new study published in Geology, researchers used computer modeling to investigate how the volcano formed, looking particularly at its asymmetrical slopes. They concluded that the Martian volcano has one steep side and one long, gradual slope because of variations in the underlying sediment. The gradual slope probably formed because it slid on something slippery like water-rich clay, they say, and pockets of water could still be trapped deep beneath the surface.
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It’s entirely possible that researchers may have detected the first ever evidence of extraterrestrial life. Researchers who spent seven years studying the atmosphere of Mars say they glimpsed discrete plumes of methane gas rising from the surface of the planet in 2003, which could have been produced by bacteria living deep underground. On Earth, a class of bacteria known as methanogens breathes out methane as a waste product [The New York Times].
Before the public could get too excited, the researchers noted that that the biological explanation is just one of two possibilities–there’s also geological processes to consider. The methane could have been produced by geothermal chemical reactions involving water and heat like those in the hot springs of Yellowstone…. [N]o signs of recent volcanism, or even any hot spots, have been spotted on Mars [The New York Times], but ancient volcanic activity could have left methane deposits trapped underground, and puffs of that gas could be routinely released. Finally, the source could be a process known as serpentinisation that occurs at low temperatures and occurs when rocks rich in the minerals olivine and pyroxene react chemically with water, releasing methane [BBC News].
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In a happy accident for science, a geothermal energy company drilling a borehole near the Hawaiian volcano Kilauea drilled right into a magma chamber, giving researchers a glimpse of a primal geological force. The unprecedented discovery could act as a “magma observatory,” allowing scientists to test their theories about how processes transformed the molten rock below Earth’s surface into the rocky crust that humans live on today [Wired News].
Volcanologist Bruce Marsh described the discovery at the ongoing meeting of the American Geophysical Union, saying that it’s “the first time a magma has been found in its natural habitat…. Before, all we had to deal with were lava flows; but they are the end of a magma’s life. They’re lying there on the surface, they’ve de-gassed. It’s not the natural habitat. It’s the difference between looking at dinosaur bones in a museum and seeing a real, living dinosaur roaming out in the field” [BBC News].
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An asteroid that crashed into the earth 65 million years ago may not have been the cause of the dinosaurs‘ extinction, a group of researchers are arguing. Instead, that impact may have been just a prelude to the main event, when a wave of volcanic eruptions spewed out massive clouds of sulfur dioxide, clouding the air and bringing showers of acid rain. The researchers are basing their theory on studies of an area in India called the Deccan Traps, which was convulsed with volcanic activity around 65 million years ago. At least four waves of massive eruptions spread successive sheets of thick basalt across the land for more than 500 miles, and they piled into a plateau more than 11,000 feet high over thousands of years [San Francisco Chronicle].
The new research on the Deccan Traps volcanoes, announced at the ongoing meeting of the American Geophysical Union, are the first major challenge to the asteroid theory that has dominated dinosaur extinction studies for three decades. That theory posits that a six-mile-wide asteroid slammed into Mexico’s Yucatan peninsula, creating the Chicxulub crater and cooling the climate so drastically that the majority of life forms went extinct in what’s known as the Cretaceous-Tertiary (or K-T) extinction. But geologist Gerta Keller and her colleagues argue that the impact occurred well before the massive die-offs began. By examining sediment layers, the team found that the crater impact appears to have occurred about 300,000 years before the K-T boundary, with virtually no effects to biota. “There is essentially no extinction associated with the impact,” Keller said [LiveScience].
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A small remote-controlled helicopter could help protect thousands of people living in the shadows of active volcanoes, according to a prize committee that awarded $100,000 to the helicopter’s inventor. Scottish volcanologist Andrew McGonigle, who just won a Rolex Award for Enterprise, flies his prototype helicopter over Italian volcanoes like Etna, Stromboli, and Vulcano, checking for a mixture of gases that indicate an imminent eruption. (DISCOVER features McGonigle in the article “Up in Smoke,” in the December issue.)
Sulfur dioxide is pushed out of volcanoes as the magma rises within, and is routinely measured by scientists from afar. However, measuring carbon dioxide can provide a better early warning system, says McGonigle. “The gases are telegrams for the earth’s interior, especially the CO2 which is released 10 kilometres deep and which comes out a long time before the magma gets to the surface,” he said [Telegraph]. Carbon dioxide is released from rising magma weeks or months before an eruption, which would give nearby residents ample time to evacuate.
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The evolution of minerals on our planet has been propelled by the evolution of life on earth, a sweeping new study demonstrates. While the underlying assumption isn’t new, the study is the first to chart how the emergence of algae and then complex microorganisms gave rise to the 4,300 or so minerals that are now present on earth.
In the early days of the universe, clouds of gas and dust contained all the naturally occurring elements found in the periodic table, but most were too widely dispersed to form minerals; scientists believe there were only about a dozen minerals in the interstellar medium. According to the study, around a further 60 different minerals formed 4.5 billion years ago, as clumps of matter collided and coalesced to begin forming the Solar System. The smaller fragments congealed into larger, planet-sized bodies, where volcanism and the effects of water took the mineral count into the hundreds. The planets Mars and Venus have got this far [Nature News], and have minerals created by hot magma like quartz and zircon.
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On October 6, NASA’s Messenger space probe swooped down to within 125 miles of the surface of Mercury, and the just-released images from that flyby are shaking up astronomers’ ideas about the planet’s geologic history. The remarkable pictures reveal a vast patch of lava, indicating that the planet was shaped by a long age of volcanic eruptions. Astronomers used to dismiss Mercury, the planet closest to the sun, as mere “dead rock,” little more than a target for cosmic collisions that shaped it, said MIT planetary scientist Maria Zuber. “Now, it’s looking a lot more interesting,” said Zuber [AP].
Messenger’s cameras spotted a crater of about 60 miles in diameter that was not as deep as other nearby craters, and determined that it had been filled in with a huge amount of solidified lava. To get an idea of how much, Zuber explains, you could imagine the entire Baltimore-Washington region covered with a layer of solidified lava about 12 times the height of the Washington monument. “So it’s a great, great deal of vulcanism,” she says. “That’s an awful lot of volcanic material in one place for such a little planet” [NPR News]. Researchers think the eruption happened between 3.8 and 4 billion years ago.
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Vials holding the results of a famous chemistry experiment conducted 55 years ago have been discovered in dusty cardboard boxes, and a new analysis of their contents has revealed fresh insights into a big question: the origin of life on earth. In 1953, chemist Stanley Miller tried to duplicate the conditions present on the primordial earth in laboratory flasks, and while some of his results were published to great acclaim, other results were packed away and forgotten–until now.
Miller’s classic experiment involved putting atmospheric components thought to reflect those of the early Earth (ammonia, hydrogen, methane, and water) in a closed system and stimulating that mixture with an electric current to mimic the effects of lightning storms. He generated a small number of biochemically significant compounds, including amino acids, hydroxy acids, and urea, showing that conditions of primitive earth can create the building blocks of life [Ars Technica]. These results generated considerable excitement, but later researchers argued that Miller was wrong about the composition of the young earth’s atmosphere, and the experiment was written off as a novelty.
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Mount Vesuvius, the mighty Italian volcano that destroyed the Roman city of Pompei, has been gradually transforming into a less menacing presence, according to a new study. Researchers studied rock samples from four different eruptions, from the Pompei disaster in 79 AD to the Pollena eruption in 472 AD, and determined the pressure and temperature conditions under which the rocks were formed; the results showed that the magma chamber had gradually shifted upward throughout the centuries. This makes eruptions less dangerous, researchers say, because magma at shallower depths is under less pressure.
Researchers keep a careful eye on the towering volcano, for good reason. The blast in 79 AD was so violent that it covered Pompeii in nearly 100 feet of ash. If Vesuvius erupted today, it could kill up to 700,000 people in southern Italy, including the residents of Naples [Scientific American]. The last eruption was in 1944, when lava flowed down the volcano’s flanks and demolished several villages and military staging grounds.
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About 93 million years ago, a burst of volcanic activity on the ocean floor led to a massive extinction event that killed one-tenth of the world’s marine invertebrates, according to a new study. The Caribbean region was the likely source of the sea-floor eruptions, says [study coauthor Steven] Turgeon. He says massive amounts of lava would have burbled and blasted up from inside the earth, setting off a “chain reaction” that took thousands of years to play out [Canwest News Service].
[T]he volcanoes spewed out metal-rich fluids that seeded the upper level of the ocean with micronutrients…. Tiny life forms on the sea surface, called phytoplankton, gorged on the food, and storing up carbon as they grew. They then sank to the sea floor and decayed, stripping the ocean of oxygen [BBC News] in a large-scale example of the phenomenon that causes the annual “dead zone” in the Gulf of Mexico. The oxygen-starved waters were a poor environment for marine life, and creatures from giant clams to tiny invertebrates went extinct.
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It’s almost as if lunar researchers got jealous of all the attention their Martian colleagues have been receiving for their discovery of water ice on Mars, and decided to compete: Lunar researchers say they’ve discovered trace amounts of water inside some moon rocks brought back by NASA’s Apollo astronauts.
A new study of volcanic glass pebbles that date from 3 billion years ago has revealed that although the planet is nearly bone dry today, it may have once harbored significant amounts of water in rocks deep below the surface. The findings challenge researchers’ understanding of how the moon formed around 4.5 billion years ago. The Moon is thought to have been created in a violent collision between Earth and another planet-sized object. Scientists thought the heat from this impact had vaporised all the water [BBC News].
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