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A pioneering deep-sea robot, which could function unmanned and untethered to a surface ship, was lost at sea this week. The loss of the 15-year-old Autonomous Benthic Explorer, or ABE, comes as a blow to scientists who study the ocean’s floor. ABE could stay under water for an entire day; it ventured into some of the most remote and risky places on earth, making detailed maps of mid-ocean ridges and was the first autonomous vehicle to locate hydrothermal vents [The Boston Globe]. That’s why it earned a spot on Wired magazine’s list of “The 50 Best Robots Ever.”

ABE was on its 222nd research dive, studying a hydrothermal vent it had discovered off the coast of Chile on the Pacific floor, when all contact was lost with its surface vessel Melville. Scientists suspect that one of the glass spheres that helped keep ABE buoyant imploded. Scientists at the Woods Hole Oceanographic Institution, who designed and built the $1 million vehicle, believe that this implosion–almost two miles undersea and under pressure of more than two tons per square inch-would have caused other spheres in ABE to implode, destroying on-board systems and leaving the robot stranded at the bottom of the ocean floor.

At the time of its loss, ABE, who was brought out of retirement as its replacement Sentry was on another expedition, was researching the Chile Triple Junction–the only place on Earth where a mid-ocean ridge is being pushed beneath a continent in a deep ocean trench [The Boston Globe]. Scientists and engineers on the ABE team reported that after a smooth launch, the final dive started normally. “ABE actively homed to its assigned position, reached the seafloor, released its descent weights, then leveled off to check its ballast. After this point, we received no more acoustic returns from the vehicle on either of its two transponders,” they said. This is when they think they lost ABE. Scientists clarified that this incident had nothing to do with the earthquake activity off the coast of Chile.

ABE was first launched in 1995 and revolutionized deep sea research; it was the precursor to today’s most sophisticated autonomous underwater vehicles (AUVs). The unmanned, untethered ABE roamed the ocean floors easily, as it was programmed to maintain a designated course but also to avoid on-course collisions. While navigating some of the most treacherous territory on earth, ABE made detailed maps of mid-ocean ridges and the 40,000-mile undersea volcanic mountain chain at the boundaries of Earth’s tectonic plates where new seafloor crust is created. It was also the first AUV to locate hydrothermal vents, where hot chemical-rich fluids spew from the seafloor and sustain lush communities of deep-sea life.  ABE explored seamounts, undersea volcanoes, and other areas with harsh, rugged terrain [Woods Hole Oceanographic Institution].

Talking about ABE’s watery end, Chris German, National Deep-Submergence Facility chief scientist said: “Abe was a vehicle that we’ll always have fond memories of— it was a world-beater in its day… In a way, it’s fitting that its demise comes on the job, and that it has gone to be recycled through the Chile subduction zone” [Nature blog].

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Image: Woods Hole Oceanographic Institution

Source: Pioneering Deep-Sea Robot Is Lost to a Watery Grave

The magnitude 8.8 earthquake that rocked Chile on February 27th didn’t just move the Earth’s axis, thereby shortening the day by 1.26 microseconds, but it also caused entire cities to shift their geographical location.

Studying precise GPS images of the area struck by the quake, a team led by earth scientist Mike Bevis discovered that the Chilean city of Concepción had moved 10 feet to the west. The epicenter of the quake was 71 miles northeast of Concepción, which is Chile’s second largest city.

The effect was widespread: The capital city, Santiago, was wrenched 11 inches west-southwest, while Beunos Aires, located nearly 800 miles from the epicenter, jumped an inch to the west. The earthquake was the fifth largest ever to be recorded by seismographs and even caused far-off areas like Fortaleza, Brazil and the Falkland Islands to change location slightly. The changes were detected by teams from The Ohio State University, the University of Hawaii, the University of Memphis and the California Institute of Technology, as well as agencies across South America [CNN].

The area where the quake hit is of particular interest to geoscientists because it is an active subduction zone, where an oceanic plate is colliding with a continental plate and being pushed into the Earth’s molten mantle below [Wired]. The world’s five largest quakes since 1900, including the largest quake ever recorded (a Chilean quake measuring 9.5), have all occurred in subduction zones. Earth scientist Ben Brooks of the University of Hawaii declared that this “earthquake will arguably become one of the, if not the most important, great earthquakes yet studied….We now have modern, precise instruments to evaluate this event” [CNN].

Image: University of Hawaii

Source: The Earth *Really* Moved: Chilean Quake Shifted a City 10 Feet to the West

Will we ever get a solid answer on what killed the dinosaurs? According to a new “K-T Boundary Dream Team” comprising of 41 international experts, including geophysicists and paleontologists, yes, the question has been settled: An asteroid is indeed to blame.

For years, scientists have argued over different theories of what killed the dinos–including one hypothesis that has gained ground recently, which suggests that massive volcanic activity in India’s Deccan Traps wiped them out 65 million years ago. However, the latest expert panel stuck to the asteroid theory, saying a massive impact wiped out the dinos and more than half of the Earth’s other species. The panel’s review was published in the journal Science.

After studying all the available data on the Cretaceous-Tertiary (K-T) mass extinction, the panel concluded that the catastrophic event was caused by a 6-mile-wide asteroid that struck Earth at an angle of 90 degrees and a speed of about 12.4 miles per second – about 20 times faster than a speeding bullet [Guardian]. The asteroid hit Chicxulub, Mexico, with a force one billion times more powerful than the atomic bomb at Hiroshima [Science Daily News].

The impact of the crash would have triggered large scale fires, landslides, earthquakes that measured 10 on the Richter scale, and subsequent tsunamis, scientists said. Debris loosened by the impact would have shrouded the planet, clouding the skies, causing a global darkness, and “killing off many species that couldn’t adapt to this hellish environment” [Science Daily News], according to study coauthor Joanna Morgan.

The scientists noted that the asteroid put an end to dinosaurs, the bird-like pterosaurs, and large marine reptiles, but it also marked a new beginning. Said study coauthor Gareth Collins: “Ironically, while this hellish day signalled the end of the 160 million year reign of the dinosaurs, it turned out to be a great day for mammals, who had lived in the shadow of the dinosaurs prior to this event. The KT extinction was a pivotal moment in Earth’s history, which ultimately paved the way for humans to become the dominant species on Earth” [Science Daily News].

The asteroid theory is far from new. The idea was first proposed by the father-son duo of Luis and Walter Alvarez three decades ago, when they found high levels of iridium in geological samples around the world. The element iridium is rare in the Earth’s crust but is common in asteroids, and can be found at asteroid impact sites. The current panel analyzed soil samples to find that immediately after the iridium layer, there is a dramatic decline in fossil abundance and species, indicating that the KT extinction followed very soon after the asteroid hit [Science Daily News].

The team also based their conclusions on “shocked” quartz. Quartz is shocked when it is hit very quickly by a huge force; shocked quartz is found only at asteroid impact locations and nuclear explosion sites. The abundance of shocked quartz in the rock layers associated with the KT boundary add further weight to the asteroid impact theory, the team declared.

Study coauthor Kirk Johnson says the team discarded the theory that large-scale volcanism made the dinosaurs extinct because the eruptions at the Deccan traps site started at least 400,000 years before the Chicxulub impact with no effect on life. The team traces the extinctions to within plus-or-minus 10,000 years of the impact 65.5 million years ago. “So we are back to where we started with the Alvarez hypothesis, a single, large, (6-mile-wide) impact,” Johnson says [USA Today].

Image: Nasa

Source: Rock-Solid Science: A 6-Mile-Wide Space Rock Did Wipe Out the Dinosaurs, Experts Say

Here we are drinking coffee and tweeting and otherwise going about our lives, generally not giving much thought to the protection that the Earth’s magnetic field affords us from the solar wind. But that magnetic field is crucial for our existence. Now, new findings in Science say that this protective shield originated even 200 million years earlier than scientists had previously thought, perhaps protecting the planet’s water from evaporating away and aiding the rise of life on the early Earth.

To know about the planet’s magnetic field three and a half billion years ago, you need iron, which records not only the direction but also the strength of the magnetic field when it forms. In South Africa, study leader John Tarduno and his team found quartz with iron tucked inside that had remained unchanged in all those years. Using a specially designed magnetometer and improved lab techniques, the team detected a magnetic signal in 3.45-billion-year-old rocks that was between 50 and 70 percent the strength of the present-day field, Tarduno says [Science News]. Three years ago he made a similar find in rocks 3.2 billion years old; thus, this find pushes back the Earth’s magnetic field at least another 200 million years.

Still, you or I wouldn’t find the Earth of that era to be terribly hospitable. In the sun’s more turbulent youth, it likely spun faster and unleashed a greater barrage of radiation. Not only was the Earth’s magnetic field strength quite a bit less than it is today, but also the magnetopause—the furthest extent of the field, where it meets the incoming solar wind—stretched only half as far out from the planet as it does today. With the magnetopause so close to Earth, the planet would not have been totally shielded from the solar wind and may have lost much of its water early on, the researchers say [Scientific American].

Pushing the existence of Earth’s magnetic field back further into the planet’s history helps fill in the picture of how life arose, the researchers argue, and it also has implications for those hunting extraterrestrial life. Life as we know it, they say, requires not only liquid water, but also the right magnetic field strength for that water to last over the long term, says Tarduno. Mars may be dry today because it lost its magnetic field early on, he adds [Science News].

There’s a lot left to learn about the protective layer that makes our lives possible. For a separate study this week in Geophysical Research Letters,  another team ran simulations of the activity in the Earth’s core and concluded that they could predict a flip in the field’s polarity—which has happened now and then during the planet’s history—with no more warning than a few decades. Some models suggest that a flip would be completed in a year or two, but if, as others predict, it lasted decades or longer we would be left exposed to space radiation. This could short-circuit satellites, pose a risk to aircraft passengers and play havoc with electrical equipment on the ground [New Scientist].

Image: John Tarduno and Rory Cottrell

Source: Earth Raised up Its Magnetic Shield Early, Protecting Water and Emerging Life

ailnlv writes “Days on Earth just got shorter. The recent earthquake in Chile shifted the planet’s axis by about 8 cm and shortened days by 1.26 microseconds ‘The changes can be modeled, though they’re difficult to detect physically given their small size… Some changes may be more obvious, and islands may have shifted… Santa Maria Island off the coast near Concepcion, Chile’s second-largest city, may have been raised 2 meters (6 feet) as a result of the latest quake…’”

Source: Chilean Earthquake Shortened Earth’s Day

Money spent unwisely on public works schemes can end up in the hands of insurgents. A U.S. nonprofit comes up with a way to track cash remotely, using GPS cameras and Google Earth.

Source: Using Google Earth and GPS to Track Afghanistan Cash

Supernova 1987A’s light reaches Earth. It’s the brightest of the 20th century, and the first visible to the naked eye since 1604.

Source: Feb 23, 1987: ‘Quintessential’ Supernova Bursts on the Scene

Four decades later, the Murchison meteorite is still full of surprises. When this extraterrestrial hunk fell to Earth near its namesake town in Australia in 1969, people managed to salvage more than 200 pounds of it. And now a new analysis of the meteorite, published this week in the Proceedings of the National Academy of Sciences, shows that it could hold millions of carbon-containing compounds. Researchers say the findings provide insight into the complex chemistry present when the chunk of space-rock formed, back when our solar system was young.

Back in 1969, researchers found amino acids and many other molecules in the carbon-rich rock.  Many researchers have analyzed the chondritic meteorite for amino acids and other possible precursors to life, because some theories hold that life on Earth began with the delivery of prebiotic organic compounds from space via asteroids or comets [Scientific American]. But scanning techniques have advanced since then, so the new team used tools like ultra-high-resolution mass spectrometry to take a fresh look at the meteorite.

In the tiny sample they crushed to study, the team turned up at least 14,000 unique organic (carbon-containing) compounds. They say that is actually conservative guess; the somewhat limited scope of their tool could have missed some, and the true number could be as high as 50,000. And because each collection of atoms can be arranged in numerous ways, the authors estimate that there may be millions of distinct organic compounds in the meteorite [Scientific American].

Not only is Murchison rich in organic compounds, it’s old. Scientists believe the Murchison meteorite could have originated before the Sun was formed, 4.65 billion years ago. The researchers say it probably passed through primordial clouds in the early Solar System, picking up organic chemicals [BBC News]. As a result, the researchers say the meteorite could have something to say about the origin of life and our solar system as it continues to let go of its secrets. It was only two years ago, after all, that scientists confirmed that the presence of subunits of DNA and RNA on Murchison were genuine, and not the result of soil contamination.

Image: Wikimedia Commons

Source: Meteorite, Maybe Older Than the Sun, Shows Chemistry of Ancient Solar System

A new analysis of the Murchison satellite — which fell to Earth in 1969, but hadn’t yet been studied with modern tools — finds several million different molecules, showing just how rich the early solar system’s matter was.

Source: New Chemical Diversity Discovered in Old Meteorite

An anonymous reader writes “Previously unknown organic molecules have been discovered in a 100 kg meteorite that hit Australia in 1969, suggesting that our early Solar System contained a soup of highly complex organic chemistry long before life appeared. Quoting: ‘According to [the study's lead author], the newly discovered compounds in the Murchison meteorite “may have contributed to the organic complexity of the early “soup” that led to the development of life on Earth. The findings also suggest that extraterrestrial chemical diversity surpasses that found on Earth. The meteor probably passed through primordial clouds in the early solar system, accumulating organic molecules in a snowball effect along the way. By tracing the sequence of organic molecules in the meteorite, researchers believe they may also be able to create a timeline for their formation and alteration since the early days of our solar system. ‘”

Source: Meteorite Contains Complex Organic Molecules