Researchers pinpoint date, rate of Earth’s most extreme extinction

By: Bill Graveland, The Canadian Press
Posted: 11/17/2011 1:14 PM | Last Modified: 11/17/2011 2:47 PM

Charles Henderson (middle) of the University of Calgary collects material from a sedimentary layer in Shangsi, Sichuan Province, China. This was one of more important sections studied for ash layers and marine fossils used to pinpoint the dates and rate of Earth's massive extinction. It's not exactly down to the day, month and year, but researchers are closer to pinpointing when most life on our planet became extinct.THE CANADIAN PRESS/HO-Charles Henderson

CALGARY – It’s not exactly down to the day, month and year, but researchers are closer to pinpointing when most life on our planet became extinct.
About 95 per cent of marine life and 70 per cent of terrestrial life became extinct about 250 million years ago when continents were all one land mass called Pangea.

A team of scientists from North America and China published a paper this week in Science which narrows down both the date and the rate of extinction.
“It may sound like it’s not very high resolution … when you compare it to the things we do today, but in terms of geological studies this is as precise as we’ve ever gotten to this point,” Charles Henderson, a professor in the geoscience department at the University of Calgary, said in an interview with The Canadian Press.

The extinction was originally believed to have occurred 251.4 million years ago. Henderson, who is a co-author of the paper, said the new estimate pegs it as happening earlier than that — about 252.2 million years ago.

The study also concludes that extinctions of most marine and terrestrial life took place simultaneously. The trigger was probably a massive release of carbon dioxide from volcanic flows in northern Russia.

“Our information narrows down the possibilities of what triggered the massive extinction and any potential kill mechanism must coincide with this time.”
Henderson’s part in the research involved the study of micro fossils. He said the tiny teeth of an extinct eel-like animal provided a relative time scale on everything from hydrocarbon deposits to global extinctions.

Other colleagues examined stable carbon isotopes. A third study involved high-resolution geo chronology. Henderson said his colleagues examined tiny crystals of zircon found within ash beds which are like “little time capsules” and hold in radioactive decay.

The analysis of various types of dating techniques on well-preserved sedimentary sections from South China to Tibet helped researchers determine when the mass extinction peaked and that it covered a span of less than 200,000 years. Most of the extinction occurred within about 20,000 years.

“These dates are important as it will allow us to understand the physical and biological changes that took place,” said Henderson.

“We do not discuss modern climate change, but obviously global warming is a biodiversity concern today. The geologic record tells us that ‘change’ happens all the time, and from this great extinction life did recover.”

via Researchers pinpoint date, rate of Earth’s most extreme extinction – Winnipeg Free Press.

NASA Launches National Polar-orbiting Operational Environmental Satellite System Preparatory Project

Posted on admin on October 28, 2011

NASA’s newest Earth-observing satellite soared into space early today aboard a Delta II rocket after liftoff at 5:48 a.m. EDT from Space Launch Complex 2 at Vandenberg Air Force Base in California.

NASA’s National Polar-orbiting Operational Environmental Satellite System Preparatory Project, or NPP, successfully separated from the Delta II 58 minutes after launch, and the first signal was acquired by the Tracking and Data Relay Satellite System. NPP’s solar array deployed 67 minutes after launch to provide the satellite with electrical power. NPP is on course to reach its sun-synchronous polar orbit 512 miles (824 km) above Earth.

“NPP is critical to our understanding of Earth’s processes and changes,” said NASA Deputy Administrator Lori Garver. “Its impact will be global and builds on 40 years of work to understand our complex planet from space. NPP is part of an extremely strong slate of current and future innovative NASA science missions that will help us win the future as we make new discoveries.”

NPP carries five science instruments, including four new state-of-the-art sensors, which will provide critical data to help scientists understand the dynamics of long-term climate patterns and help meteorologists improve short-term weather forecasts. The mission will extend more than 30 key long-term datasets NASA has been tracking, including measurements of the ozone layer, land cover, and ice cover.

NPP serves as a bridge mission between NASA’s Earth Observing System (EOS) of satellites and the next-generation Joint Polar Satellite System, a National Oceanic and Atmospheric Administration (NOAA) program that will also collect weather and climate data.

Scientists will use NPP data to extend and improve upon EOS data records. These satellites have provided critical insights into the dynamics of the entire Earth system, including clouds, oceans, vegetation, ice, solid Earth and atmosphere. NPP will allow scientists to extend the continuous satellite record needed to detect and quantify global environmental changes.

“The measurements from NPP will benefit science and society for many years to come,” said Michael Freilich, director of NASA’s Earth Science Division. “NPP will help improve weather forecasts, enable unique scientific insights, and allow more accurate global environmental predictions. I’m confident that the strong partnerships forged in the NPP program between NASA and NOAA, industry, and the research and applications communities will ensure the success of the mission.”

The satellite will be operated from the NOAA Satellite Operations Facility in Suitland, Md. NASA will operate NPP for the first three months after launch while the satellite and instrument are checked out. NPP operations will then be turned over to NOAA and the JPSS program for the remainder of the mission.

NPP data will be transmitted once every orbit to a ground station in Svalbard, Norway, and to direct broadcast receivers around the world. The data will be sent back to the United States via fiber optic cable to the NOAA Suitland facility. NPP data is then processed into data records that NASA and NOAA will make available through various data archives.

The Delta II launch vehicle that delivered NPP into orbit also deployed auxiliary payloads within 98 minutes after launch. The five small “CubeSat” research payloads are the third in a series of NASA Educational Launch of Nanosatellite missions, known as ELaNa missions.

The NPP mission is managed by NASA’s Goddard Space Flight Center in Greenbelt, Md., for the Earth Science Division of the Science Mission Directorate at NASA Headquarters in Washington. The Joint Polar Satellite System program provides the NPP ground system. NOAA will provide operational support for the mission. Launch management is the responsibility of the NASA Launch Services Program at the Kennedy Space Center in Florida.
Source: NASA

via NASA Launches National Polar-orbiting Operational Environmental Satellite System Preparatory Project.

Thick Haze Protected First Life on Earth

Jeanna Bryner | Date: 03 June 2010 Time: 08:04 AM ET

A thick organic haze cloaked early Earth several billion years ago and may have kept the planet from freezing over, protecting primordial life from the damaging effects of the sun’s ultraviolet rays, a new study suggests.

The haze, made from methane and nitrogen chemistry in the upper atmosphere, would have been analogous to the cloudy curtain hovering above Saturn’s largest moon, Titan, the researchers say.

The results help solve a longstanding mystery called the faint young sun paradox: While geological evidence suggests early Earth was ice-free, climate models haven’t been able to get the planet warm enough for such a wet, toasty world.

"Since climate models show early Earth could not have been warmed by atmospheric carbon dioxide alone because of its low levels, other greenhouse gases must have been involved," said lead researcher Eric Wolf, a doctoral student at the University of Colorado at Boulder. "We think the most logical explanation is methane, which may have been pumped into the atmosphere by early life that was metabolizing it."

The findings are published in the June 4 issue of the journal Science.

Early Earth

During the Archean period some 3.8 billion to 2.5 billion years ago, the sun’s output may have been between 20 percent and 30 percent fainter than today, meaning fewer rays, Wolf said. However, previous work by other scientists suggests Earth’s surface temperatures were as warm or warmer than today.

Scientists have long tried to figure out how our planet was warmed. In the 1970s, Carl Sagan and George Mullen proposed early Earth’s atmosphere was full of methane and ammonia and that did the warming trick. This idea fell out of favor in the 1980s and early 1990s, when scientists figured it was actually a carbon dioxide-rich atmosphere that warmed Earth. That also fell out of favor when geological evidence began showing there was a limit to how much carbon dioxide could’ve been in the atmosphere.

Then, about a decade ago scientists suggested a methane-rich atmosphere kept Earth toasty. The problem: A mix of methane and nitrogen produces a haze that was first thought to cause significant cooling. But in this “cooling” model, the haze particles were assumed to be spheres.

Fluffy fractals

That probably wasn’t the case, as Wolf and CU colleague Owen B. Toon found out. They ran computer simulations using a climate model from the National Center for Atmospheric Research and concepts about Titan’s odd haze learned from lab studies by another CU group.

Laboratory studies show that the haze enshrouding early Earth was made up of irregular “chains” of aggregate particles whose geometric sizes were larger than spheres. The particle shapes actually seemed to match those of aerosols believed to populate Titan’s dense atmosphere.

They were likely fluffy looking fractals. The fractal nature of the particles means the haze would have sufficiently shielded Earth from UV light and allowed gases like ammonia to build up, causing greenhouse warming and perhaps helping to keep the planet from freezing over.

“Without a UV shield ammonia is destroyed quickly from high-energy photons,” Wolf told LiveScience.

The fractal particles also would’ve let visible wavelengths pass through to warm the planet.

In order for the fractal haze to pull this warming off, Wolf’s team estimated about 100 million tons of haze were produced annually in the atmosphere of early Earth during the Archean.

“If this was the case, an early Earth atmosphere literally would have been dripping organic material into the oceans, providing manna from heaven for the earliest life to sustain itself,” Toon said.

Methane mystery

“In our model the haze requires methane. It is easy to get methane in our model if you assume we are starting at post-biotic Earth,” Wolf said. “If we step back into the pre-biotic Earth it is a bit harder to find where this methane is coming from.”

That’s the “big question mark now,” Wolf said. If they do find an abiotic source of methane, such as from volcanoes or deep-sea ridges, that would be “very exciting,” he added.

Even while looking into the future, Wolf points out the findings bring scientists back to Sagan’s ideas.

“This study is a step forward but it also has led us back to our original ideas,” Wolf said.

via Thick Haze Protected First Life on Earth | LiveScience.