Earth Archives

January 23, 2010December 24, 2015 by Ken Kremer

NASA advanced Solar Observatory nearing February launch; will send IMAX like movies daily

SDO and two piece payload fairing inside “clean room” at Astrotech Spaceflight facility near KSC on Jan 21. Fairing protects spacecraft during ascent through earths atmosphere. Credit: Ben Cooper/Spaceflight Now

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NASA’s new solar science satellite, dubbed the Solar Dynamics Observatory, or SDO, moved an important step closer to launch when it was encapsulated inside its two piece payload fairing on Thursday (Jan 21) at the Astrotech Space Operations Facility nearby to the Kennedy Space Center (KSC). SDO is the most sophisticated spacecraft ever designed and constructed to study the sun and its dynamic behavior.

Liftoff of SDO aboard an Atlas V rocket from Cape Canaveral Air Force Station is targeted for Feb 9, just 2 days after the shuttle Endeavour blasts off with the Tranquility module and heads for the ISS.

“SDO will revolutionize our view of the sun. It will reveal how solar activity affects our planet and help us anticipate what lies ahead”, said Madhulika Guhathakurta at a Jan 21 press briefing. She is the SDO program scientist at NASA Headquarters.

The enclosed observatory will be transported on a specially designed trailer to Launch Complex 41 on Tuesday (Jan. 26) and then be hoisted up and bolted atop the two stage booster rocket. The 19 story tall Atlas V will propel the 8,800 pound spacecraft into an inclined geosynchronous orbit where it will study the sun in multiple wavelengths during its 5 year primary mission. It carries sufficient fuel to operate for another 5 years.

An Atlas rocket similar to this vehicle I observed at Cape Canaveral Pad 41 will launch SDO. Credit: Ken Kremer

SDO arrived at KSC on July 9 for final processing, testing and fueling operations. It was shipped from NASA’s Goddard Space flight Center where it was built by teams of technicians, engineers and scientists at a cost of $848 million.

SDO is the first spacecraft to be launched as part of NASA’s Living with a Star (LWS) science program initiative. The goal is to better understand the causes of solar variability and to create better forecasts for predicting “space weather” which directly affects the Earth and all life inhabiting it. Furthermore, this information will be used to help protect and provide early warning to valuable satellites operating in space as well as astronaut crews working aboard the International Space Station.

When active regions on the sun erupt suddenly and violently in the form of a solar flare or coronal mass ejection (CME), they hurl millions of tons of solar material and charged particles toward Earth which can damage orbiting satellites, disrupt navigation systems and cause failures in the power grid.

SDO is equipped with 3 science instruments which will measure and characterize in-depth the Suns interior and atmosphere, magnetic field, hot plasma of the solar corona and the density of the radiation that creates the ionosphere of the planets.

SDO will collect huge volumes of data which amount to a staggering 1.5 terabytes per day. This is the equivalent of downloading a half million songs each day or filling a CD every 36 seconds. “That’s almost 50 times more science data than any other mission in NASA history”, says Dean Pesnell, the SDO project scientist at NASA Goddard.

SDO is enclosed in its payload fairing and ready for transport on Jan 26 to Atlas V launch pad. Credit: NASA/Jim Grossman

“SDO is going to send us images ten times better than high definition television” according to Pesnell. “The pixel count is comparable to an IMAX movie — an IMAX filled with the raging sun, 24 hours a day.”

“We’ll be getting IMAX-quality images every 10 seconds,” says Pesnell. “We’ll see every nuance of solar activity.” Because no orbiting spacecraft has ever come even close to this incredible speed, there is a vast potential for ground breaking science discoveries. Scientists hope to learn how storms are generated inside the sun and how they then evolve and propagate outwards through the suns atmosphere and towards earth and the rest of the solar system.

Since SDO has no on-board recording system, the data will be transmitted continuously on a 24/7 basis to dedicated receiving stations on the ground in New Mexico as it maintains position over 22,000 miles high above earths equator.

I will be reporting on site from the Kennedy Space Center in February and directly from the launch pads for both SDO and STS 130. See my earlier STS 130 reports here.

NASA SDO Website

December 18, 2009December 24, 2015 by Nancy Atkinson

Deep, Fiery Undersea Volcano Captured on Video

The orange glow of magma is visible on the left of the sulfur-laden plume. The area shown in this image is approximately six feet across in an eruptive area approximately the length of a football field that runs along the summit. (Image courtesy of NSF, NOAA, and WHOI Advanced Imaging and Visualization Lab)

Ever seen fire and smoke under water before? Oceanographers using a remotely operated underwater vehicle discovered and recorded the first video and still images of the deepest underwater volcano actively erupting molten lava on the seafloor. The ROV Jason vehicle captured the powerful event nearly 1.2 km (4,000 feet) below the surface of the Pacific Ocean, in the “Ring of Fire” region, near Fiji, Tonga and Samoa. “It was very exciting. We’ve never seen anything like that on the ocean floor,” said Bob Embley, a marine geologist with NOAA, who described the event an underwater Fourth of July. “When we started to see red flashes of light, everyone was extremely excited. Then we had to get down to the work of actually understanding of what we were seeing.”

The scientists presented their findings, along with HD video at the American Geophysical Union’s fall meetings in San Fransciso. The video was taken in May of 2009, and the science team said the undersea volcano is likely to still be erupting, and may have started activity in late 2008.

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Embly said the eruption couldn’t be seen above the water, but there were “water column anomlies which indicated an eruption going on. We knew within a few hundred feet where the eruption was taking place.”

There were actually two erupting regions, but the video shows the most dramatic one. Visible in the video is magma – sometimes fiery, red hot at 1,371 C (2,500 degrees F) – bursting up through the seawater, with fragments of rock being propelled and magma flowing down the slope of the volcano. Hot sulfer “smoke” plumes can also be seen.

The volcano is spewing a type of lava known as Boninite, which until now had only been seen in extinct volcanoes more than a million years old.

A underwater “hydrophone” recorded the sound, and it was synched with the video.

The ROV Jason is designed and operated by the Woods Hole Oceanographic Institution for the National Deep Submergence Facility.

Samples collected near the volcano showed the seawater to be highly acidic, similar to battery or stomach acid, the researchers said. Despite the harsh conditions, scientists found and photographed a species of shrimp apparently thriving near the volcanic vents.

“Nobody would have predicted that things would have survived long enough in water that acidic. It seems like it’s too harsh a condition,” said University of Washington chemical oceanographer Joseph Resing.

They hope to go back in a few months and see all the other creatures that have taken up residence there.

Sources: WHOI, NOAA, NSF, AGU press conference

December 10, 2009December 24, 2015 by Nancy Atkinson

Earth’s Atmosphere Came from Outer Space

A new study from the University of Heidelberg suggests that flash-heating and carbon depletion could have been intrinsic to the emergence and evolution of life on Earth. Credit: NASA

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A new study finds the gases which formed the Earth’s atmosphere – as well as its oceans – did not come from inside the Earth but from comets and meteorites hitting Earth during the Late Heavy Bombardment period. A research team tested volcanic gases to uncover the new evidence. “We found a clear meteorite signature in volcanic gases,” said Dr. Greg Holland the project’s lead scientist. “From that we now know that the volcanic gases could not have contributed in any significant way to the Earth’s atmosphere. Therefore the atmosphere and oceans must have come from somewhere else, possibly from a late bombardment of gas and water rich materials similar to comets.”

Holland said textbook images of ancient Earth with huge volcanoes spewing gas into the atmosphere will have to be rethought.

According to the theory of the Late Heavy Bombardment, the inner solar system was pounded by a sudden rain of solar system debris only 700 million years after it formed, which likely had monumental effects on the nascent Earth. So far, the evidence for this event comes primarily from the dating of lunar samples, which indicates that most impact melt rocks formed in this very narrow interval of time. But this new research on the origin of Earth’s atmosphere may lend credence to this theory as well.

The researchers analyzed the krypton and xenon found in upper-mantle gases leaking from the Bravo Dome gas field in New Mexico. They found that the two noble gases have isotopic signatures characteristic of early Solar System material similar to me teorites instead of the modern atmosphere and oceans. It therefore appears that noble gases trapped within the young Earth did not contribute to Earth’s later atmosphere.
The study is also the first to establish the precise composition of the Krypton present in the Earth’s mantle.

“Until now, no one has had instruments capable of looking for these subtle signatures in samples from inside the Earth – but now we can do exactly that,” said Holland.

The team’s research, “Meteorite Kr in Earth’s Mantle Suggests a Late Accretionary Source for the Atmosphere” was published in the journal Science.

Sources: Science, EurekAlert

November 25, 2009December 24, 2015 by Jon Voisey

Jupiter – Our Silent Guardian?

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We live in a cosmic shooting gallery. In Phil Plait’s Death From the Skies, he lays out the dangers of a massive impact: destructive shockwaves, tsunamis, flash fires, atmospheric darkening…. The scenario isn’t pretty should a big one come our way. Fortunately, we may have a silent guardian: Jupiter.

Although many astronomers have assumed that Jupiter would likely sweep out dangerous interlopers (an important feat if we want life to gain a toehold), little work has been done to actually test the idea. To explore the hypothesis, a recent series of papers by J. Horner and B. W. Jones explores the effects of Jupiter’s gravitational pull on three different types of objects: main belt asteroids (which orbit between Mars and Jupiter), short period comets, and in their newest publication, submitted to the International Journal of Astrobiology, the Oort cloud comets (long period comets with the most distant part of their orbits far out in the solar system). In each paper, they simulated the primitive solar systems with the bodies in question with an Earth like planet, and gas giants of varying masses to determine the effect on the impact rate.

Somewhat surprisingly, for main belt asteroids, they determined, “that the notion that any ‘Jupiter’ would provide more shielding than no ‘Jupiter’ at all is incorrect.” Even without the simulation, the astronomers say that this should be expected and explain it by noting that, although Jupiter may shepherd some asteroids, it is also the main gravitational force perturbing their orbits and causing them to move into the inner solar system, where they may collide with Earth.

Contrary to the popular wisdom (which expected that the more massive the planet, the better it would shield us), there were notably fewer asteroids pushed into our line of sight for lower masses of the test Jupiter. Also surprisingly, they found that the most dangerous scenario was an instance in which the test Jupiter had 20% in which the planet “is massive enough to efficiently inject objects to Earth-crossing orbits.” However, they note that this 20% mass is dependent on how they chose to model the primordial asteroid belt and would likely change had they chosen a different model.

When the simulation was redone for for short period comets, they again found that, although Jupiter (and the other gas giants) may be effective at removing these dangerous objects, quite often they did so by sending them our way. As such, they again concluded that, as with asteroids, Jupiter’s gravitational jiggling was more dangerous than it was helpful.

Their most recent treatise explored Oort cloud objects. These objects are generally considered the largest potential threat since they normally reside so far out in the solar system’s gravitational well and thus, will have a greater distance to fall in and pick up momentum. From this situation, the researchers determined that the more massive the planet in Jupiter’s orbit, the better it does protect us from Oort cloud comets. The attribute this to the fact that these objects are initially so far from the Sun, that they are scarcely bound to the solar system. Even a little bit of extra momentum gained if they swing by Jupiter will likely be sufficient to eject them from the solar system all together, preventing them from settling into a closed orbit that would endanger the Earth every time it passed.

So whether or not Jupiter truly defends us or surreptitiously nudges danger our way depends on the type of object. For asteroids and short period comets, Jupiter’s gravitational agitation shoves more our direction, but for the ones that would potentially hurt is the most, the long period comets, Jupiter does provide some relief.

November 20, 2009November 3, 2021 by Nancy Atkinson

What If Earth Had Rings?

Earth's Rings over San Bernadino. Credit: Kevin Gill (CC BY-SA 2.0)

Here’s a video that poses — and answers — an interesting question: what would Earth look like if it had rings like Saturn? This animation was done by artist Roy Prol, and it shows not only how the rings would look from space, but also the view Earthlings would have of the rings.

Prol says the ring views from Earth’s surface were created according to the location’s latitude and the viewer’s orientation, and that the size of the rings was calculated respecting the Roche limit for the Earth. As you can se in the video, the rings would look different, depending on where you were on our planet. A very intriguing concept, and the video is very well done.

The only bad thing about Earth having rings is that we probably wouldn’t have our beautiful Moon. Imagine, instead of all the songs, poems and paintings of the Moon over the past centuries, we’d have odes to our rings.

One of our favorite image editing artists is Kevin Gill, and he’s also created imagery of Earth having rings, such as our lead image, which shows Earth’s Rings over San Bernadino, California and this one, below:

Earth’s Rings from New Hampshire. Credit: Kevin Gill (CC BY-SA 2.0)

October 26, 2009December 24, 2015 by Nancy Atkinson

The Stats Are In: No Global Cooling

Global Temperature graph. Credit: National Climatic Data Center, via the Associated Press.

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The idea that the world is now cooling has been repeated in opinion columns, talk radio, pundit television and more. After a poll was released last week indicating that only 57 percent of Americans now believe there is strong scientific evidence for global warming, which is down from 77 percent in 2006, Seth Borenstein from the Associated Press decided to check out what the statistics are really saying about global warming or cooling. In a blind test, Borenstein sent accumulated ground temperature data from the past 130 years to four independent statisticians. He disguised the sources (NASA, NOAA and British meteorological data) and didn’t tell the statisticians what the numbers represented; he asked them to just look for trends in the data. The experts found no true temperature declines over time; additionally, the last ten years comprise not only the highest data set in the record, but they also have a continued, positive trend.

It seems recent weather trends have been cool — 2008 was cooler than previous years, especially the really hot years of 1998 and 2005.

Global land and ocean temperature indexes. Credit: Goddard Institute for Space Studies.

Borenstein wanted to know if this was a longer climate trend or just weather’s normal ups and downs. All four of the statisticians agreed independently the statistics overall clearly show an upward trend of warming. Also included was a data set of satellite temperature data that is often favored by skeptics of global warming. Same story there: global temps are on the rise.

The ups and downs during the last decade, which some skeptics say show a cooling rather than warming, are variations that are repeated randomly in data as far back as 1880.

One statistician said that “cherry-picking” a micro-trend within a bigger trend is not the way to look at data.

This “blind” review of the data isn’t the only review that has shown obvious warming. Borenstein said that NOAA recently re-examined its data because of the recent “chatter” about cooling, and no cooling trend was found, and earlier this year, climate scientists in two peer-reviewed publications statistically analyzed recent years’ temperatures against claims of cooling and found them not valid.

For the full story, read Borenstein’s article here.

Source: Associated Press

September 28, 2009December 24, 2015 by Fraser Cain

Picture of Earth from Space

Looking for a picture of Earth from Space? Here is a collection.

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Here’s a spectacular image of the earth with the full coverage of the Pacific Ocean. This image was obtained by the Galileo spacecraft on December 12, 1990 while on its way to planet Jupiter 1.6 million miles from the Earth.

This is a spectacular full view of our planet earth. It was taken by the Apollo 17 during their journey to the moon in December 7, 1972. The south polar ice cap of Antarctica can be clearly seen in the image. This region constitutes 70% of the world’s freshwater. This photo of the earth was the first to feature the south polar ice cap.

Here’s an image of different storms and hurricanes forming at the Atlantic Ocean. This image was generated using the data provided by the Geostationary Operational Environmental Satellite (GOES) satellite on September 3, 2008.

Here’s a nice view of the earth particularly focusing on the Western Hemisphere. Earth is the third planet from the sun and is the only place in the universe where life is known to exist.

This is a nice view of the planet earth and the moon in one frame as seen from the Galileo spacecraft 6.2 million kilometers away.

Here’s a picture of Earth from Space as well as the Moon. These images were taken separately and then stitched together on computer to show them together.

This picture was taken by the Space Shuttle, and shows the Earth from high orbit. You can see how the clouds rise up into the atmosphere.

Here’s another picture of Earth. Again, this was taken from the space shuttle.

This is a satellite map that shows all of the Earth.

This is the classic “Blue Marble” photo of Earth.

Earth from Space at Night

Here’s a photo of the entire Earth, seen from space at night. You can easily see cities and towns in North America, Asia and Europe. And you can also see vast regions of the Earth which are totally dark.

Here’s a photo of the city of Chicago at night. It might look upside down, but that’s because it was captured from the International Space Station as it was passing over the city.

This night space image shows the city of Tokyo at night. The blue green glow in the photograph comes from the mercury vapor lighting that lines the streets of the city.

This space pic from night shows the city of London. You can see the brightest areas are the most densely populated, and the less dense areas are dimmer. You can see the ring road that surrounds London, as well as the path of the Thames river.

Here’s one of the brightest cities in the world. It’s Los Angeles from space, seen at night.

Earth at Night Wallpaper — A Crescent Earth at Midnight

Here’s an amazing picture of the earth in crescent. This breathtaking view of our planet was obtained by the Geostationary Operational Environmental Satellite (GOES-8) on June 22, 1996. GOES is primarily assigned in monitoring the weather particularly the development of storms and hurricanes in different parts of the earth.

This is an amazing still photo of the earth taken during its transition from day to night. This beautiful photo was taken from the International Space Station in June 2001.

This spectacular image of the crescent earth was captured by the Optical Spectroscopic and Infrared Remote Imaging System (OSIRIS) camera on board the Rosetta spacecraft in November 2007.

Here’s a nice view of Houston, Texas at night as seen from the International Space Station on February 28, 2010. This photo was taken by the crew member of the Expedition 22 mission. Houston, Texas is the world’s energy capital.

Earth from Orbit

Here’s an image of the Manicougan Reservoir situated at Canadian Shield in the province of Quebec. This was taken from the International Space Station in December 1983. Manicougan Reservoir covers an area of about 1,942 km².

This image of the sunset on earth was captured from the International Space Station by an Expedition 13 astronaut in August 10, 2006. Expedition 13 mission was able to accomplish a total of 2,886 orbits.

This photo shows the Central Gulf Coast obtained from the International Space Station by an Expedition 11 astronaut in September 10, 2005.

This is a photo of the eye of Hurricane Alberto taken in August 19, 2000 during the Terra orbit 3571. Hurricane Alberto is a Category 3 hurricane in the Atlantic that lasted for 19.75 days.

This beautiful view of the eye of Hurricane Emily and the moon was captured from the International Space Station in July 16, 2005. Hurricane Emily is a Category 5 hurricane having a maximum wind speed of 160 mph.

Earth from the Space Shuttle

Earth from Space Shuttle — Sunrise in Space

This photo of the earth’s atmosphere during sunrise was taken in July 2005 by a Discovery crew member during the STS-114 mission. STS-114 mission was the first Return to Flight mission after the unfortunate loss of the Columbia space shuttle.

This image of the earth was taken from the space shuttle Endeavor during the STS-59 mission in April 12, 1994. The image particularly shows the shuttle’s payload bay and the region of the Andes Mountains in Bolivia.

Here’s a stunning image of the Sinai Peninsula and the Mediterranean Sea as seen from the space shuttle Atlantis. A crew member of the STS-125 mission took this photo during the mission’s first flight in space.

Here’s a unique photo of the earth’s atmosphere taken by the crew members of Atlantis’ STS-125 mission during its preparation for landing on May 20, 2009.

Here’s a great view of the Aurora Australis taken in May 1991 by the STS-39 crew member onboard the space shuttle.

We have written many articles about pictures of Earth from Space for Universe Today. Here’s a story about the Earth from space at night, and here’s an article about images of cities from space.

You can get many more images of Earth from space at NASA’s Earth Observatory website.

We have recorded a whole episode of Astronomy Cast about our planet. Listen to it here, Episode 51: Earth.

July 21, 2009December 24, 2015 by Anne Minard

Heat-Shocked Diamonds Provide New Clue of Horse-Killing Impact

California's Channel Islands, where heat-shocked soot and diamonds are suggesting a killing comsic impact. Courtesy NOAA and UC Santa Barbara

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Archeologists have been divided about whether an extraterrestiral impact blasted North America about 12,900 years ago, wreaking havoc on Earth’s surface and sending scores of species — including a pygmy mammoth and the horse — into oblivion.

New clues from California’s Channel Islands should put any doubt to rest, says an international team of researchers.

This transmission electron microscopy close-up shows a single lonsdaleite crystal, left, and associated diffraction pattern. Credit: University of Oregon

The 17-member team, led by University of Oregon archaeologist Douglas J. Kennett, has found what may be the smoking gun.

The team has found shock-synthesized hexagonal diamonds in 12,900-year-old sediments on the Northern Channel Islands off the southern California coast.

The tiny diamonds and diamond clusters were buried deeply below four meters (13 feet) of sediment. They date to the end of Clovis — a Paleoindian culture long thought to be North America’s first human inhabitants. The nano-sized diamonds were pulled from Arlington Canyon on the island of Santa Rosa, which had once been joined with three other Northern Channel Islands in a landmass known as Santarosae.

The diamonds were found in association with soot that forms in extremely hot fires, and they suggest associated regional wildfires, based on nearby environmental records.

Such soot and diamonds are rare in the geological record. They were found in sediment dating to massive asteroid impacts 65 million years ago in a layer widely known as the K-T Boundary. The thin layer of iridium-and-quartz-rich sediment dates to the transition of the Cretaceous and Tertiary periods, which mark the end of the Mesozoic Era and the beginning of the Cenozoic Era.

“The type of diamond we have found — Lonsdaleite — is a shock-synthesized mineral defined by its hexagonal crystalline structure. It forms under very high temperatures and pressures consistent with a cosmic impact,” Kennett said. “These diamonds have only been found thus far in meteorites and impact craters on Earth and appear to be the strongest indicator yet of a significant cosmic impact [during Clovis].”

The age of this event also matches the extinction of the pygmy mammoth on the Northern Channel Islands, as well as numerous other North American mammals, including the horse, which Europeans later reintroduced. In all, an estimated 35 mammal and 19 bird genera became extinct near the end of the Pleistocene with some of them occurring very close in time to the proposed cosmic impact, first reported in October 2007 in PNAS.

Source: University of Oregon, via Eurekalert. The results appear in a paper online ahead of print in the Proceedings of the National Academy of Sciences.

July 17, 2009December 24, 2015 by Anne Minard

Solar Cycle Triggers La Nina, El Nino-like Climate Shifts

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Researchers have discovered a link between the 11-year solar cycle and tropical Pacific weather patterns that resemble La Niña and El Niño events.

When it comes to influencing Earth’s climate, the Sun’s variability pales in recent decades compared to greehouse gases — but the new research shows it still plays a distinguishable part.

The total energy reaching Earth from the sun varies by only 0.1 percent across the solar cycle. Scientists have sought for decades to link these ups and downs to natural weather and climate variations and distinguish their subtle effects from the larger pattern of human-caused global warming.

Co-authors Gerald Meehl and Julie Arblaster, both affiliated with the National Center for Atmospheric Research in Boulder, Colorado, analyzed computer models of global climate and more than a century of ocean temperature records. Arblaster is also affiliated with the Australian Bureau of Meteorology.

In the new paper and a previous one with additional colleagues, the researchers have been able to show that, as the sun’s output reaches a peak, the small amount of extra sunshine over several years causes a slight increase in local atmospheric heating, especially across parts of the tropical and subtropical Pacific where Sun-blocking clouds are normally scarce.

That small amount of extra heat leads to more evaporation, producing extra water vapor. In turn, the moisture is carried by trade winds to the normally rainy areas of the western tropical Pacific, fueling heavier rains.

As this climatic loop intensifies, the trade winds strengthen. That keeps the eastern Pacific even cooler and drier than usual, producing La Niña-like conditions.

“We have fleshed out the effects of a new mechanism to understand what happens in the tropical Pacific when there is a maximum of solar activity,” Meehl said. “When the sun’s output peaks, it has far-ranging and often subtle impacts on tropical precipitation and on weather systems around much of the world.”

The result of this chain of events is similar to a La Niña event, although the cooling of about 1-2 degrees Fahrenheit is focused further east and is only about half as strong as for a typical La Niña.

True La Niña and El Nino events are associated with changes in the temperatures of surface waters of the eastern Pacific Ocean. They can affect weather patterns worldwide.

Although the Pacific pattern in the new paper is produced by the solar maximum, the authors found that its switch to an El Niño-like state is likely triggered by the same kind of processes that normally lead from La Niña to El Niño.

The transition starts when the changes of the strength of the trade winds produce slow-moving off-equatorial pulses known as Rossby waves in the upper ocean, which take about a year to travel back west across the Pacific.

The energy then reflects from the western boundary of the tropical Pacific and ricochets eastward along the equator, deepening the upper layer of water and warming the ocean surface.

As a result, the Pacific experiences an El Niño-like event about two years after solar maximum — also about half as strong as a true El Niño. The event settles down after about a year, and the system returns to a neutral state.

“El Niño and La Niña seem to have their own separate mechanisms,” Meehl said, “but the solar maximum can come along and tilt the probabilities toward a weak La Niña. If the system was heading toward a La Niña anyway,” he adds, “it would presumably be a larger one.”

The study authors say the new research may pave the way toward predictions of temperature and precipitation patterns at certain times during the approximately 11-year solar cycle.

In an email, Meehl noted that previous work by his team and other research groups has shown that “most of the warming trend in the first half of the 20th Century was due to an increasing trend of solar output, while most of the warming trend in the last half of the 20th Century and ever since has been due to ever-increasing GHG (greenhouse gas) concentrations in the atmosphere from the burning of fossil fuels.”

The new paper appears this month in the Journal of Climate, a publication of the American Meteorological Society. (Sorry, it’s not yet available online.)

Source: Eurekalert

July 17, 2009December 24, 2015 by Anne Minard

Ancient Domes Reveal 3.45-billion-year-old Life History

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Ancient, dome-like rock structures contain clues that life was active on Earth 3.45 billion years ago, according to new research — and the findings could help shed light on life’s history on Earth and other planets, including Mars.

Abigail Allwood, who studies planetary habitability at NASA’s Jet Propulsion Laboratory, led the research. She and her colleagues studied stromatolites, which are dome- or column-like sedimentary rock structures formed in shallow water, layer by layer, over long periods of geologic time.

Geologists have long known that the large majority of the relatively young stromatolites they study—those half a billion years old or so—have a biological origin; they’re formed with the help of layers of microbes that grow in a thin film on the seafloor.

The microbes’ surface is coated in a mucilaginous substance to which sediment particles rolling past get stuck.

“It has a strong flypaper effect,” said John Grotzinger, a Caltech geologist and a study co-author. In addition, the microbes sprout a tangle of filaments that almost seem to grab the particles as they move along. “The end result,” Grotzinger explains, “is that wherever the mat is, sediment gets trapped.”

So in a young stromalite, dark bands like those seen in the close-up cross section at left indicate organic material. But 3.45 billion years ago, in the early Archean period of geologic history, things weren’t quite so simple.

“Because stromatolites from this period of time have been around longer, more geologic processing has happened,” Grotzinger says. Pushed deeper toward the center of Earth as time went by, these stromatolites were exposed to increasing, unrelenting heat. This is a problem when it comes to examining the stromatolites’ potential biological beginnings, he explains, because heat degrades organic matter. “The hydrocarbons are driven off,” he says. “What’s left behind is a residue of nothing but carbon.”

As such, geologists debate whether or not the carbon found in these ancient rocks is diagnostic of life.

Allwood and her team turned to the texture and morphology of the rocks themselves, from samples gathered in Western Australia. The samples, says Grotzinger, were “incredibly well preserved.” Dark lines of what was potentially organic matter were “clearly associated with the lamination, just like we see in younger rocks. That sort of relationship would be hard to explain without a biological mechanism.”

Allwood set about trying to find other types of evidence. She looked at what she calls the “microscale textures and fabrics in the rocks, patterns of textural variation through the stromatolites and—importantly—organic layers that looked like actual fossilized organic remnants of microbial mats within the stromatolites.”

She saw “discrete, matlike layers of organic material that contoured the stromatolites from edge to edge, following steep slopes and continuing along low areas without thickening.” She also found pieces of microbial mat incorporated into storm deposits, which disproved the idea that the organic material had been introduced into the rock more recently, rather than being laid down with the original sediment.

“In addition,” Allwood notes, “Raman spectroscopy showed that the organics had been ‘cooked’ to the same burial temperature as the host rock, again indicating the organics are not young contaminants.”

Allwood said she, Grotzinger, and their team have collected enough evidence that it’s no longer a great leap to accept the stromatolites as biological in origin. And the researchers say the implications of the findings don’t stop at life on Earth.

“One of my motivations for understanding stromatolites,” Allwood says, “is the knowledge that if microbial communities once flourished on Mars, of all the traces they might leave in the rock record for us to discover, stromatolite and microbial reefs are arguably the most easily preserved and readily detected. Moreover, they’re particularly likely to form in evaporative, mineral-precipitating settings such as those that have been identified on Mars. But to be able to interpret stromatolitic structures, we need a much more detailed understanding of how they form.”

Both images courtesy of Abigail Allwood.

Source: Eurekalert, a media service of the American Association for the Advancement of Science (AAAS). The research appeared in online June 10 and in print June 16 in the Proceedings of the National Academy of Sciences (PNAS).