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| Autumn Equinox: 5 Odd Facts About Fall!

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Autumn Equinox: 5 Odd Facts About Fall ~ Jeanna Bryner, Managing Editor, Live Science.

The pools have closed and crisp temperatures and crunchy leaves are on their way. Today (Sept. 22) marks the end of summer and the beginning of fall, also called the autumn equinox, in the Northern Hemisphere.

The autumn equinox occurs today at 4:44 p.m. EDT (20:44 UTC) when the sun is directly in line with Earth’s celestial equator, or the equator projected onto the sky. Day and night last about equally long on Sunday, with about 12 hours of light and 12 hours of dark. This same phenomenon occurs on the spring equinox, which will next occur on March 20.

The date of the fall equinox (and its spring counterpart) varies slightly each year, sometimes falling on the 23rd or 24th depending on the quirks of the calendar, along with Earth’s slightly irregular orbit. Here are five surprising facts about fall and the autumn equinox.

The colorful foliage of autumn

A carpet of fallen leave beneath nearly bare trees, with green grass in the background serving as a memory of summer gone by.
Credit: goran cakmazovic

The pools have closed and crisp temperatures and crunchy leaves are on their way. Today (Sept. 22) marks the end of summer and the beginning of fall, also called the autumn equinox, in the Northern Hemisphere.

The autumn equinox occurs today at 4:44 p.m. EDT (20:44 UTC) when the sun is directly in line with Earth’s celestial equator, or the equator projected onto the sky. Day and night last about equally long on Sunday, with about 12 hours of light and 12 hours of dark. This same phenomenon occurs on the spring equinox, which will next occur on March 20.

The date of the fall equinox (and its spring counterpart) varies slightly each year, sometimes falling on the 23rd or 24th depending on the quirks of the calendar, along with Earth’s slightly irregular orbit. Here are five surprising facts about fall and the autumn equinox.

1. Amazing light shows

In addition to the brilliant colors of fall leaves, the autumn equinox signals another colorful spectacle — the aurora borealis, also called theNorthern Lights. Besides the lengthening of nights and cool evening weather, which are great for stargazers, autumn truly is “aurora season,” according to NASA. That’s because geomagnetic storms are about twice as frequent as the annual average during the fall. [Aurora Photos: Northern Lights Dazzle in Night-Sky Images]

Particles that get discharged from the sun during such geomagnetic storms zip toward Earth at breakneck speed. As the particles slam into Earth’s magnetic field, they bump into atoms and molecules of oxygen, nitrogen and other elements. The result? Dazzling light shows, with hues most commonly of pink, green, yellow, blue, violet and occasionally orange and white — depending on what elements the particles collide with.

2. Animals respond, testes swell

Living things respond to the light changes that come with fall, with trees shedding their leaves and animals preparing for hibernation. Fall can bring an especially noticeable change to the high-attitude-livingmale Siberian hamster. That’s because the rodent’s testes swell up 17 times their size from short days to long; the swelling allows, in part, the animals to time reproduction properly.

Hamsters aren’t the only creatures to herald in fall in strange ways. When autumn hits, the black-capped chickadee goes gangbusters collecting seeds and hiding them in hundreds of different spots in trees and on the ground. At the same time, the tiny bird’s hippocampus balloons by 30 percent as new nerve cells pop up in this part of the brain, which is responsible for spatial organization and memory.

3. Full moon named for autumn

Autumn gets its own full moon, the Harvest Moon. From Wolf and Sturgeon to Hunter and Harvest, full moons are named for the month or season in which they rise. The Harvest Moon is the full moon closest to the autumn equinox, which occurred on the night of Sept. 18-19 this year.

Before artificial lighting, farmers took advantage of the full moon’s light to harvest their crops. In late summer and early autumn, many crops ripen all at once, making lots of work for farmers who had to stay in the fields after sundown to harvest all the goods. Such moonlight became essential to their harvest, and the Harvest Moon emerged, according to NASA.

4. Why fall leaves may fade

Climate change may dull the picture most synonymous with autumn — fall leaves. Leaves change their wardrobes in response to chilly temperatures and less light (as days begin to shorten); they stop producing chlorophyll, the green pigment that helps leaves capture sunlight to power photosynthesis. As green fades, the leave’s other pigments, such as the orange and yellow of carotenoids shine through. Vibrant red hues are the result of anthocyanins, pigments that are produced in the fall. [Photos of Turning Leaves: The Rich Colors of Fall Foliage]

These autumn colors could be some of the casualties of global warming, say scientists. Research has shown as the world warms, fall-colored leaves are delayed since their cues to change color come partly from cooling temperatures.

Fall’s cool nights and sunny days also help to trigger trees like the sugar maple to store their anthocyanins temporarily in their leaves, giving leaf peepers a show of red. But if global warming leads to warmer nights, paired with autumn’s shortening days, trees may not use their sugars to make red pigments, instead sending that fuel to twigs or burning it off, according to Howie Neufeld, a plant physiologist at Appalachian State University in North Carolina.

Climate change may also alter suitable habitats for trees like the sugar maple known to be big players in fall’s vibrant colors.

5. When is the equinox?

The autumnal equinox falls on different dates each year, usually Sept. 22, like this year, or Sept. 23; but in 1931, the equinox happened on Sept. 24. The reason: The Gregorian calendar doesn’t match up perfectly with the position of Earth in its orbit around the sun.

As Earth orbits the sun, it revolves around its axis at a 23.5-degree angle so that it is pointed directly toward the sun at the summer solstice, directly away from the sun during the winter solstice, and at a right angle with the sun on the equinoxes; that right angle means the sun shines about equal amounts of light across the Northern Hemisphere on the equinoxes. If this trek around the sun took exactly 365 days, Earth would be in its autumn equinox position on the same day each year. Since Earth takes 365.25 days to make a complete journey around the sun, the date is slightly different each year. The fall equinox won’t happen again on Sept. 24 until 2303.

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| Origin of gold – is it from outer space?

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Does gold come from outer space? ~ William Kremer, BBC World Service.

The idea that gold came from outer space sounds like science fiction, but it has become well-established – it’s pretty much received opinion in the field of earth sciences. How did this bizarre theory take hold, and is it here to stay?

A man holding a nugget of gold and the planet earth

For the chieftains of pre-Columbian America, the dazzling yellow stuff they found glinting at the bottom of streams or buried in the rocky ground captured the power of the sun god. They dressed themselves in battle armour wrought from the enchanted metal, believing it would protect them.

They were sadly deceived.

Gold, an unusually soft metal, wasn’t any match for the steel of the Spanish. But the Native Americans may well have been right in believing the element was otherworldly.

“Why do you find nuggets of gold on the surface of the Earth?” asks science writer John Emsley. “The answer to that, is that they’ve arrived here from space in the form of meteorites.”

This theory has come in the last few decades to be held by the majority of scientists as a way of explaining gold’s abundance. There may only be 1.3 grams of gold per 1,000 tonnes of other material in the Earth’s crust (the rocky shell of the planet that is around 25 miles thick) but that’s still too much to fit with the standard models of our planet’s formation.

Meteoric milestones

A meteor storm
  • It is thought the Earth was created by a process of “accretion” – dust and gas were moulded into meteorites and small planets that crashed together, forming larger bodies
  • Soon after Earth reached its current dimensions a crash with an object the size of Mars is thought to have tilted it on its axis and created the moon
  • A spike in meteoric activity took place about 500m years later – the terminal bombardment – which scientists still can’t completely explain
  • Earth’s craters from this period have been softened by tectonic activity that does not take place on the moon, which is why it appears less pock-marked

After its birth four-and-a-half billion years ago, the surface of the Earth heaved with volcanoes and molten rock. Then, over tens of millions of years, most of the iron sank down through the outer layer, known as the mantle, to the Earth’s core. Gold would have mixed with the iron and sunk with it. Matthias Willbold, a geologist at Imperial College London, likens the process to droplets of vinegar collecting at the bottom of a dish of olive oil.

“All the gold should be gone,” he says.

It isn’t though. So science has had to come up with an explanation, and the answer currently favoured is – a meteoric shower.

“The theory is that after the core formed there was a meteoric shower that struck the Earth,” says Willbold. “These meteorites contained a certain amount of gold and that replenished the Earth’s mantle and the continental crust with gold.”

Willbold says the theory fits with the pattern of meteorite activity as scientists understand it, climaxing with a huge storm that took place more than 3.8 billion years ago, referred to as the “terminal bombardment”. The meteorites punched out the craters we see on the moon and came from an asteroid belt that still exists between Earth and Mars.

This idea of the gold-laden-meteorite “veneer” was first proposed following the Apollo moon landings of the 1970s. Scientists examining rock samples from the moon’s mantle found much less iridium and gold than they did in samples from the surface of the moon or from the earth’s crust and mantle. It was proposed that the moon and Earth had been battered by iridium-rich meteorites, known as chondrites, from outer space. While the precious fallout from this meteoric shower lay scattered on the surface of the moon, on Earth the planet’s internal activity had churned it into the mantle too.

The idea, called the “late veneer hypothesis”, has become a fundamental theory in planetary science.

It also helps to explain many other anomalies in the Earth’s composition – it is thought that the same meteorites delivered the carbon, nitrogen, water and the amino acids that are vital to all life on the planet.

Graphic showing the late veneer theory

“They are basically the building blocks of Earth,” says Willbold.

Two years ago, he and a team from the universities of Bristol and Oxford examined some rocks from Greenland which had their origins in a part of the Earth’s mantle that was insulated from meteorite activity for a crucial period some 600 million years. The team did not look at the gold content of the 4.4-billion-year-old rocks, but at tungsten. Tungsten has some similarities to gold but exists in different forms or isotopes, and this provides scientists with more historical information.

“The tungsten-isotopic composition of these rocks was basically really different from the tungsten-isotopic composition of other rocks,” says Willbold.

He infers that the Greenland rocks are a remnant of Earth’s composition prior to the start of the late veneer meteorite shower, postulated to have taken place between 4.4 and 3.8 billion years ago.

A lady trying on a gold necklace

The Why Factor is broadcast on BBC World Service on Fridays at 18:30 GMT

Willbold’s influential study, published in Nature in September 2011, provides the most compelling evidence yet for the late veneer hypothesis. This hypothesis seems the best explanation for the unusual tungsten-isotopic profile of Willbold’s Greenland rocks, just as it seemed to explain the different quantities of gold and iridium in the mantles of the Earth and the Moon in the 1970s.

But the hypothesis has been challenged.

Last year, Mathieu Touboul and a team from the University of Maryland examined some different rocks, this time from Russia and significantly younger than those in the Greenland study – a mere 2.8 billion years old.

These younger rocks had their full complement of elements known as siderophiles – the iron-loving group of metals that includes gold – but in terms of tungsten isotopes, the rocks turned out to be very similar to Willbold’s. And yet they date from after the time proposed for the late veneer bombardment.

“We reach a different conclusion about what is generating these tungsten anomalies inside the rocks,” says Touboul. He thinks differences in the Earth’s mantle might have caused tungsten isotopes to develop in different ways.

Touboul though still believes the late veneer hypothesis is right – he just doesn’t think that tungsten isotope measurements provide a demonstration of it.

Other scientists think it’s time for a major rethink.

The “magma ocean” theory

Diagram showing the magma ocean theory
  • Some gold and palladium sank to the centre of the Earth, but some remained dissolved in the mantle, to eventually reappear in the crust
  • This theory currently still requires a veneer of meteorite activity to explain the relative abundance of different elements

“I used to accept the late veneer hypothesis back when we had so little data that it seemed to be a sensible interpretation, but I think it’s past its prime now,” says Munir Humayun of Florida State University.

“It seemed so elegant, but there were so many gaps in the data. We presumed a lot and knew very little back then.”

Humayun says the original 1970s studies on moon and Earth rocks produced imprecise results, at variance with more sophisticated follow-up studies from the 1990s.

One of these studies, from the University of Maryland, found less resemblance than expected between the Earth’s rocks and chondrites – the iridium-rich meteorites. “This is where the late veneer failed in my opinion,” says Humayun. “The answer came back that none of the known meteorite types were anything like the veneer.”

Scientists also began to find metals like gold much deeper in the Earth’s mantle than they had anticipated. This could be explicable if the Earth underwent a much bigger meteoric barrage than originally supposed, and at an earlier point in time. But the way Humayun sees it, the late veneer hypothesis stopped answering old questions – and started posing new ones.

He is one of a small group of scientists who subscribe to an alternative theory. Their proposition is that all the gold in the Earth’s crust – or the overwhelming majority of it – was here on Earth all along. Most of it certainly alloyed with iron and migrated to the Earth’s core, but a significant proportion – perhaps 0.2% – dissolved into a 700km deep magma “ocean” within the Earth’s outer mantle.


Munir Humayun

“Why the analytical community likes the idea (of a late veneer) so much is something that continues to trouble me” ~ Munir Humayun, Florida State University

Later, the gold was brought back up to the crust by volcanic action. This is the stuff we wear round our necks and on our fingers today.

This theory requires gold and other siderophile elements to be more soluble than has previously been thought, otherwise insufficient quantities would have dissolved in the magma.

Experiments by two scientists at Nasa – Kevin Righter and Lisa Danielson – indicate that gold’s solubility in mantle rocks does increase with high pressures and temperatures.

However, it has not yet been possible to measure in a lab the solubility of all the highly siderophile elements over the full range of temperatures and pressures of the Earth’s mantle, so for now this proposed explanation for the abundance of gold also remains no more than a hypothesis. But it is attracting interest and was bashed against the late veneer theory at length in a session last month at geochemistry’s annual international symposium – the Goldschmidt Conference in Florence.

Matthias Willbold, who attended the session, says the consensus in the room was that the late veneer hypothesis was still the best explanation for the unusual tungsten-isotopic profile of his Greenland rocks.

He adds that, unlike Humayun, most scientists believe that chondritic meteorites are a “match” for concentrations of metals in the Earth’s mantle and crust. But he says he accepts that the case for the late veneer hypothesis is not exactly sewn-up.

“You can never be absolutely sure,” he says. “But the beauty of our model at the moment is that all the numbers match up very well.” His isotope measurements indicate that about 0.5% of the Earth’s mantle mass fell in the form of meteorites (that’s 20 billion billion tonnes, if you were wondering). This figure matches geologists’ current best guess, based on the overall concentrations of precious metals in the Earth’s mantle and crust. Willbold describes this match as a “smoking gun”.

A gold prospector
For now it remains unproven why there is just so much gold on Earth

But Humayun says that the extent to which geochemists believe it depends on their precise field of study.

Analytical geochemists – the group of researchers that measures trace elements in rocks – have come to see their research as crucial to understanding the emergence of life on Earth. Humayun says that experimental geochemists – the group of scientists attempting to recreate the conditions of the mantle in the lab – are more open-minded.

“It’s about how you make your money! If you’re an experimentalist, then you’re eating the late veneer guys’ lunch by doing these experiments.

“Why the analytical community likes the idea (of a late veneer) so much is something that continues to trouble me. It’s because of this relevance they have tied in to the origin of life. There’s a lot riding on it!”

The Why Factor is broadcast on BBC World Service on Fridays at 18:30 GMT. Listen to the gold episode via iPlayer or The Why Factor download.

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| Earth life ‘may have come from Mars!’

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Earth life ‘may have come from Mars’ ~ Simon Redfern, BBC.

Gale crater, MarsLife would face challenges on Mars today, but billions of years ago conditions might have been better

Life may have started on Mars before arriving on Earth, a major scientific conference has heard.

New research supports an idea that the Red Planet was a better place to kick-start biology billions of years ago than the early Earth was.

The evidence is based on how the first molecules necessary for life were assembled.

Details of the theory were outlined by Prof Steven Benner at the Goldschmidt Meeting in Florence, Italy.

Scientists have long wondered how atoms first came together to make up the three crucial molecular components of living organisms: RNA, DNA and proteins.

“

The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock”

Prof Steven BennerWestheimer Institute for Science and Technology

The molecules that combined to form genetic material are far more complex than the primordial “pre-biotic” soup of organic (carbon-based) chemicals thought to have existed on the Earth more than three billion years ago, and RNA (ribonucleic acid) is thought to have been the first of them to appear.

Simply adding energy such as heat or light to the more basic organic molecules in the “soup” does not generate RNA. Instead, it generates tar.

RNA needs to be coaxed into shape by “templating” atoms at the crystalline surfaces of minerals.

The minerals most effective at templating RNA would have dissolved in the oceans of the early Earth, but would have been more abundant on Mars, according to Prof Benner.

This could suggest that life started on the Red Planet before being transported to Earth on meteorites, argues Prof Benner, of the Westheimer Institute of Science and Technology in Gainesville, US.

The idea that life originated on Mars and was then transported to our planet has been mooted before. But Prof Benner’s ideas add another twist to the theory of a Martian origin for the terrestrial biosphere.

Red or deadHere in Florence, Prof Benner presented results that suggest minerals containing the elements boron and molybdenum are key in assembling atoms into life-forming molecules.

The researcher points out that boron minerals help carbohydrate rings to form from pre-biotic chemicals, and then molybdenum takes that intermediate molecule and rearranges it to form ribose, and hence RNA.

Shergottite meteorite from Mars
Meteorites from Mars have been arriving on Earth throughout our planet’s history

This raises problems for how life began on Earth, since the early Earth is thought to have been unsuitable for the formation of the necessary boron and molybdenum minerals.

It is thought that the boron minerals needed to form RNA from pre-biotic soups were not available on early Earth in sufficient quantity, and the molybdenum minerals were not available in the correct chemical form.

Prof Benner explained: “It’s only when molybdenum becomes highly oxidised that it is able to influence how early life formed.

“This form of molybdenum couldn’t have been available on Earth at the time life first began, because three billion years ago, the surface of the Earth had very little oxygen, but Mars did.

“It’s yet another piece of evidence which makes it more likely life came to Earth on a Martian meteorite, rather than starting on this planet.”

Early Mars is also thought to have had a drier environment, and this is also crucial to its favourable location for life’s origins.

“What’s quite clear is that boron, as an element, is quite scarce in Earth’s crust,” Prof Benner told BBC News, “but Mars has been drier than Earth and more oxidising, so if Earth is not suitable for the chemistry, Mars might be.

“The evidence seems to be building that we are actually all Martians; that life started on Mars and came to Earth on a rock,” he commented.

“It’s lucky that we ended up here, nevertheless – as certainly Earth has been the better of the two planets for sustaining life. If our hypothetical Martian ancestors had remained on Mars, there may not have been a story to tell.”

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| Just a Few Words, From God: On Iron!

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Just a Few Words, From God: On Iron ~ Supererogatory.

Stars are powered by fusion; in their superhot cores, the lightest elements are pressed together, by almost unimaginable force, into heavier elements, unleashing furious bursts of energy, which we perceive as light, though like the fullness of the world, we can only physically capture, through our eyes, part of this output. As stars die, they seek, almost like living beings, to desperately fuse, out of heavier elements, still heavier elements, but their cause is doomed. They die.

Some unimaginably—the weightiest become black holes, disappearing from our horizons—some spectacularly—they implode and explode—and some sadly—fading away, into small and pathetic things. But through their deaths comes life. Yours and mine.   It is fusion, and specifically the fusion at the desperate end of a star’s lifespan, that produces the heavier elements, which in turn have rained down onto Earth from comets and comes into us from afar—needless to say, these elements, which include the elements necessary for our existence, do not come “from” the Earth, but from the cosmos around the Earth.

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It is not terribly inaccurate thus to say: Life here began out there.  (When I first posted this to Facebook, a friend added: Iron has the highest binding energy per nucleon, making it the most stable. When stars are making bigger and bigger elements from fusion, they eventually generate iron. However, since iron is so stable, it actually takes more energy to fuse iron into a heavier element. At this point, the star is unable to produce more energy, and it eventually collapses and dies because of this. So that verse in Surat Hadid is additionally significant because Iron specifically is the ‘strongest’ element from the perspective of stellar evolution.)

And then I came across the 25th verse of Surat al-Hadid, which includes this passage: ‘…And we sent down iron.’ Just like that. One simple verb, into which centuries of human knowledge are collapsed. God has spoken Truth. The Universe is His imagination, just as you and I are. Be and it is. And we are. The verb, “anzala” (anzalna, ‘We make descend’) is the same verb, from the same root, as we use for revelation—as in His Word, coming down to us via Muhammad, peace be upon him.

He sent down iron. 

Muhammad Iqbal, the great South Asian philosopher, said the Qur’an includes 3 types of signs (in Arabic, ayahs): The verses themselves (ayahs), historical evidences, and the natural world. Literally then iron is a sign of His Will and His Presence, just as Revelation is, and both came to us from outside and beyond the world, and it is to that realm which we cannot perceive, but which we feel especially in this month, that we are called back. No matter what you are going through right now, and maybe you’re in a bad place, remember this.

He made you not for this place, but for another. And He calls us back.

truth 01

May we be joined in the gardens beyond description and entered into the company of those we love and those we admire, and may we be given peace, may we be healed of all our hurts, forgiven all our wrongs, elevated beyond ourselves, and given fullness and fulfillness in His shade. On these nights, when the heavens are apparent to us—step outside the mosque, and look up, just for a moment—think of what he sends down for us, and how this speaks to His creation of us, but what comes down comes down only for this reason: For us to ascend.

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| Earth’s 6-Year Twitch Changes Day Length!

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Earth’s 6-Year Twitch Changes Day Length ~ Becky Oskin, Live Science.

Earth's magnetic field
Supercomputer model of Earth’s magnetic field.
CREDIT: NASA

Periodic wobbles in Earth’s core change the length of a day every 5.9 years, according to a study published today (July 10) in the journal Nature.

Teasing out this subtle cycle, which subtracts and adds mere milliseconds to each day, also revealed a match between abrupt changes in the length of day and Earth’s magnetic field. During these short-lived lurches in the magnetic field intensity, events called geomagnetic jerks, Earth’s day also shifts by 0.1 millisecond, the researchers report. Since 1969, scientists have detected 10 geomagnetic jerks lasting less than a year.

Seemingly negligible, these fleeting variations are mighty to those who study the planet and its core. All of a sudden, a planet changes its spin like a figure skater open or closing her arms. The rotational effect helps scientists understand what’s happening inside theEarth’s core. Shifts in the magnetic field also provide clues to the inaccessible iron core. But their source remains a mystery.

Lead study author Richard Holme suspects a shimmy in the solid inner core that drives the 5.9-year cycle, transferring angular momentum to the outer core. But no one knows what causes geomagnetic jerks.

“I have no clue,” said Holme, lead study author and a geophysicist at the University of Liverpool in the U.K. “Something is happening at the core-mantle boundary, because you’re seeing the geomagnetic and the rotational effect at the same time, but we don’t know what’s going on,” Holme told LiveScience‘s OurAmazingPlanet.

What’s up down there?

Researchers still actively debate how the fluid outer core produces our planet’s protective magnetic field, which has weakened and flipped polarity many times in geologic history. [What if Earth’s Magnetic Poles Flip?]

Earth's layers

Scientists believe that gyrating iron fluid generates Earth’s magnetic field, like a giant dynamo. Both yearly and millennial-scale changes in the field have been attributed to the swirling, spinning outer core. Tracking changes in the magnetic field helps researchers create models of how the dynamo may work.

“Essentially, we are using the variations as a tracer for flow,” said Mathieu Dumberry, a geophysicist at the University of Alberta in Canada, who was not involved in the study.

Since geomagnetic jerks were first discovered in 1969, researchers have sought to explain and model how Earth’s dynamo produces these quick changes in the magnetic field.

Finding a connection with changes in the length of day provides a new way of thinking about the phenomenon, Holme said.

For example, the results could help modelers better understand how the core and mantle exchange angular momentum, Holme said. Perhaps electromagnetic friction creates torque, akin to an electric car battery. But the electrical conductivity of the lower mantle (or the ease with which electrical charges flow within it) can’t be too high, or it would cause a delay in the magnetic field responding to the rotational shift, Holme said. Instead, Holme and co-author Olivier de Viron of the Institut de Physique du Globe in Paris saw simultaneous geomagnetic jerks and jumps in the length of day.

“We’ve got some ideas, but it’s just me having an amused flight of fancy. I’m a data hound, and I want to propel thinking about this,” Holme said.

But Dumberry is not convinced that the study proves a link between jerks and changes in day length. “In that, it’s not such a strong story,” he said. There is a remarkable correlation between a geomagnetic jerk in 2003 and a length of day change, but earlier links aren’t as strong, he said.

Length of day oscillates

Other forces also change the planet’s spin. Since Earth formed, tugging from the sun and moon have slowed the planet’s rotation. On shorter time scales, earthquakes, melting glaciers, ocean currents and strong winds, such as the jet stream, can alter how fast the planet spins, shortening or lengthening a day by about 1 millisecond.

Holme and de Viron removed these external and planetary effects from five decades of length of day data, exposing the 5.9-year period. They then compared bumps in the cycle, which correspond to sudden jumps in the length of day, with geomagnetic jerks detected since 1969.

Dumberry praised the pair’s careful work in extracting the 5.9-year signal. “This multiyear length of day signal is the best so far,” he said.

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| Neoproterozoic era: Evidence oceans flowed on ‘Snowball Earth!’

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Evidence Oceans Flowed on ‘Snowball Earth’ ~  Charles Q. Choi, OurAmazingPlanet Contributor, LiveScience.com.

When ice possibly swathed the entire world, the oceans underneath may have nevertheless surprisingly churned, potentially helping to provide life with vital nutrients, new research suggests.

For decades, scientists have proposed that the planet may once have been a “Snowball Earth,” with geological evidence suggesting ice reached all the way to the equator at least twice during the Neoproterozoic era (about 635 million to 750 million years ago) in stints lasting millions of years. The ice sheets blanketing Earth were not completely solid — there were likely many holes or thin patches around warm spots such as volcanoes — but in many other places, ice may have been more than a half-mile thick.

During these Snowball Earth periods, it is also thought that ancient life may have begun its drive toward explosive diversity. However, until now, little was done to model how water and nutrients might have flowed in the ice-capped oceans in which this primordial life dwelled. Past research did suggest that oceans might have flowed sluggishly due to ice shielding the waters from wind, and such relatively stagnant water would not have been as conducive to driving the developing diversity of primordial life in the oceans. But such studies failed to account for geothermal heat from the planet that could potentially drive ocean mixing, researchers said.

Snowball Earth oceans

To simulate oceans during Snowball Earth times, a group of scientists developed a high-resolution 3D model of the oceans and continents during the Neoproterozoic. The simulation accounted for weak geothermal heat and about 3,300 feet (1 kilometer) of ice covering the land and oceans. The findings are detailed in the March 7 issue of the journal Nature.

Surprisingly, the researchers found the oceans were not stagnant pools during a Snowball Earth — rather, they were quite dynamic. [50 Amazing Facts About Earth]

“It’s counterintuitive,” said team member Daniel Schrag, a geologist at Harvard University. “Our assumption, and I think everyone else’s, was that when you had ice keeping winds from mixing the oceans, you would end up with relatively stagnant oceans.”

Geothermal heat would cause water at the ocean bottom to rise, triggering the kind of convection seen in pots of boiling water. In fact, water temperature and saltiness would have effectively been uniform across all depths nearly everywhere, a pattern completely different from that expected during any other period in Earth’s history, researchers said.

“The ocean today is much more stratified — you have warm, buoyant water on top and cold, dense water on the bottom, and it resists mixing, although it does mix because of tides and winds,” Schrag said. “In the snowball ocean, everything almost has the same density, so it takes much less energy to mix the oceans, and it turns out to mix very well.”

Ocean mixing

In addition, powerful currents would have wrapped around the equator, and strong upwelling would have existed along the coasts. Unstable flows at the equator would have caused eddies that in turn would have generated jet streams reminiscent of those seen in the atmosphere of Jupiter, the researchers added. This circulation, including that of warm water, suggests melting rates near continents may have been as much as 10 times larger than previously estimated.

“You really have to think about Snowball Earth as being like a different planet,” Schrag told OurAmazingPlanet. “Some criticisms people have made about the Snowball Earthhypothesis are based on assumptions of how the Earth worked that depend on how Earth works today. I think these findings are another nice example of how Snowball Earth was a very different planet, even though it’s this planet. When you cover Earth with ice for so long, it changes many things you think are fundamental, including ocean circulation.”

And all this churning might have helped provide life under the ice with a regular flow of nutrients.

“The ice-covered ocean was a pretty hard place to live — it’s not a booming ecosystem,” Schrag said. “This model makes us think harder about how nutrients would have mixed in the snowball, how oxygen and carbon might mix. It suggests there was really quite vigorous ocean-mixing.”

Future research should investigate ancient rocks to look for evidence to test their model, Schrag added.

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| NASA X-rays the Moon + gets a Theory of Life on Mars!

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Via the Moon, a Theory of Life on Mars ~ , The Atlantic.

NASA captures, quite literally, gravity’s rainbow.

 

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A gravitational map of the moon, depicting newly quantified lunar mass: Red indicates more massive areas and blue indicates less mass (NASA/JPL-Caltech/MIT/GSFC)

Scientists care about the moon in part because it is the moon — our moon. But they care about it, also, because its body is in some ways a proxy for our Earth’s: Its surface, like ours, bears the scars of a long existence in our little corner of the Milky Way. And new research suggests that that existence might have been much more violent — and perhaps more hospitable to life — than we humans initially believed. Yes.

The story begins, officially, around five years ago. In 2007, the Japanese lunar satellite Kaguya released two small probes into orbit around the moon. Those satellites, working in tandem, created the first gravity map of the far side of the moon — a chart that showed, in color-coded detail, the variations in mass on our nearest planetary neighbor.

The same year, NASA announced plans for a similar mission: the launch of twin spacecraft that would spend several months doing their own moon-mapping work, measuring the lunar gravity field in unprecedented detail. In late 2011, NASA began that mission, sending a pair of spacecraft — collectively known as GRAIL (Gravity Recovery and Interior Laboratory) — to orbit the lunar surface. The pair of satellites (named, awesomely, Ebb and Flow) fly in formation around the moon, sending each other — and Earth — microwave measurements of our only natural satellite. The twin vehicles, each about the size of a washing machine, work by detecting tiny changes in the distance between them — variations caused by lunar mountains, craters, and subsurface mass concentrations.

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An artist’s rendering of GRAIL’s twin spacecraft, flying in tandem orbits around the moon (NASA/JPL)

The GRAIL satellites and their operators use a technique pioneered by GRACE, the Gravity Recovery and Climate Experiment, launched in 2002 and run jointly by NASA and the German Aerospace Center. The Grace satellites have been taking detailed measurements of Earth’s gravity field — tracking, in particular, gravity changes related to the movement of mass within Earth (like, say, the melting of ice at its poles and changes in its ocean circulations). GRAIL has been applying the lessons of GRACE to our planetary neighbor — helped along by the fact that the moon lacks an atmosphere, which allows the satellites to orbit wonderfully close to its surface: between 10 and 30 miles above the lunar crust. (The ESA’s GOCE satellite, which does gravitational mapping of Earth, has to stay 10 times farther away from its target to avoid atmospheric drag.)

So. Between March and May of 2012, the Ebb and Flow satellites essentially X-rayed the moon, assessing our nearest planetary neighbor both from and beyond its surface. Scientists took measurements from the moon’s crust to its core to reveal both the moon’s subsurface structures and — indirectly — its thermal history. And partial results of that work are reflected in the amazing graphic shown above, which is, GRAIL says, the highest-resolution map of this kind ever generated for a celestial body. The colors in question represent the variations in the moon’s structure, with red indicating more massive areas and blue representing less-massive.

And here, along those lines, is a map depicting the bulk density of the lunar highlands on both the near (left) and far (right) sides of the moon — generated using both gravity data from the GRAIL mission and topography data from NASA’s Lunar Reconnaissance Orbiter. Solid circles correspond to prominent impact basins. White denotes regions that contain mare basalts (thin lines) and that were not analyzed; red corresponds to higher than average densities; and blue corresponds to lower than average densities.

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A graphic depicting the bulk density of the lunar highlands on the near and far sides of the moon. (NASA/JPL-Caltech/ IPGP)

So what do these maps actually mean? Well, first, consider the craters. The color-coding suggests that the moon was pummeled by impacts that were much more violent than previously assumed. The moon’s crust is pretty much covered by craters — and, if those impacts were caused by asteroids and other space debris, it would stand to reason that Earth, along with Mercury, Venus, and Mars — our nearest neighbors — once endured similar punishment. As Maria Zuber, GRAIL’s principal investigator, put it in a press conference announcing the findings: The discovery “really opens a window to this early stage of just what a violent place the surfaces of all terrestrial planets were early in their history.”

The data also suggest that the moon’s crust is thinner than previously thought — just 21 to 27 miles. (Earlier estimates had it ranging from 30 to 40 miles deep.) And underneath that crust, Ebb and Flow detected several large, linear structures — structures, composed of solidified magma, that can run for up to 300 miles. Those lunar “dikes” are covered by craters, which would suggest that they predate most of the moon’s violent impacts. And they could have formed, most interestingly, only if the moon’s crust were extending — only if the moon’s interior were heating up and expanding.

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An artist’s rendering of a planetary collision near the star Vega: The Moon may have formed from the debris of this kind of impact between Earth and a Mars-sized body. (NASA)

This gives more evidence in favor of the Giant Impact hypothesis, the leading theory for the moon’s origin — a theory suggesting that the moon was formed from the fragments of Earth that gathered after a Mars-size body smashed into our planet about 4.5 billion years ago. A warmer-on-the-inside/cooler-on-the-outside moon would be consistent with that kind of coalescent lunar formation. As GRAIL guest scientist Jeff Andrews-Hanna noted in the team’s press conference: “This had been predicted theoretically a long time ago, but there was no direct observational evidence to support this period of early lunar expansion until this GRAIL data.”

And! Finally! The new information about the moon also suggests some evidence for a theory of how life might exist, or have existed, on other rocky planets. Because the cracks on the moon’s surface could provide a pathway for fluids — which might explain what happened to the ocean that some scientists believe once existed on the surface of, yes, Mars. As Zuber noted, “that ocean could well be underground.” As the Martian surface dried out, the sub-surface water could have provided a hospitable environment for any microbes that were living on the planet’s surface. Microbes, Zuber said, “could have gone very deep within the crust of Mars.”

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| Black Marble Vid [2m] – Night Time Earth in HD!

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Night Time Earth in HD ~ .

 

 

In daylight our big blue marble is all land, oceans and clouds. But the night – is electric.

This view of Earth at night is a cloud-free view from space as acquired by the Suomi National Polar-orbiting Partnership Satellite (Suomi NPP). A joint program by NASA and NOAA, Suomi NPP captured this nighttime image by the satellite’s Visible Infrared Imaging Radiometer Suite (VIIRS). The day-night band on VIIRS detects light in a range of wavelengths from green to near infrared and uses filtering techniques to observe signals such as city lights, gas flares, and wildfires. This new image is a composite of data acquired over nine days in April and thirteen days in October 2012. It took 312 satellite orbits and 2.5 terabytes of data to get a clear shot of every parcel of land surface.

This video uses the Earth at night view created by NASA’s Earth Observatory with data processed by NOAA’s National Geophysical Data Center and combined with a version of the Earth Observatory’s Blue Marble: Next Generation.

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| Salty Life: Ancient Microbes Found in Antarctic Lake‏!

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Ancient Microbes Found in Antarctic Lake‏ ~ NASA.

Nearly 65 feet beneath the icy surface of a remote Antarctic lake, scientists from NASA, the Desert Research Institute (DRI) in Reno, Nev., the University of Illinois at Chicago, and nine other institutions, have uncovered a community of bacteria existing in one of Earth’s darkest, saltiest and coldest habitats.

Lake Vida, the largest of several unique lakes found in the McMurdo Dry Valleys, contains no oxygen, is mostly frozen and possesses the highest nitrous oxide levels of any natural water body on Earth. A briny liquid, which is approximately six times saltier than seawater, percolates throughout the icy environment where the average temperature is minus 8 degrees Fahrenheit. The international team of scientists published their findings online Nov. 26, in the Proceedings of the National Academy of Sciences Early Edition.

Lake Vida (splash)

Scanning electron micrograph of very small and numerous bacterial cells inhabiting icy brine channels in Antarctica’s Lake Vida, which lies in the Victoria Valley, one of the northernmost of the Antarctic dry valleys. Credit: Christian H. Fritsen, Desert Research Institute

“This study provides a window into one of the most unique ecosystems on Earth,” said Alison Murray, a molecular microbial ecologist and polar researcher at the DRI and the report’s lead author. “Our knowledge of geochemical and microbial processes in lightless icy environments, especially at subzero temperatures, has been mostly unknown up until now. This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments.”

Despite the very cold, dark and isolated nature of the habitat, the report finds the brine harbors a surprisingly diverse and abundant variety of bacteria that survive without a current source of energy from the sun. Previous studies of Lake Vida dating back to 1996 indicate the brine and its inhabitants have been isolated from outside influences for more than 3,000 years.

“This system is probably the best analog we have for possible ecosystems in the subsurface waters of Saturn’s moon Enceladus and Jupiter’s moon Europa,” said Chris McKay, a senior scientist and co-author of the paper at NASA’s Ames Research Center, Moffett Field, Calif.

Murray and her co-authors and collaborators, including Peter Doran, the project’s principal investigator at the University of Illinois at Chicago, developed stringent protocols and specialized equipment for their 2005 and 2010 field campaigns to sample from the lake brine while avoiding contaminating the pristine ecosystem.

Lake Vida (field camp)

Research field camp on Lake Vida, Victoria Valley.

“The microbial ecosystem discovered at Lake Vida expands our knowledge of environmental limits for life and helps define new niches of habitability,” said Adrian Ponce, co-author from NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who enumerated viable bacterial spore populations extracted from Lake Vida.

To sample unique environments such as this, researchers must work under secure, sterile tents on the lake’s surface. The tents kept the site and equipment clean as researchers drilled ice cores, collected samples of the salty brine residing in the lake ice and assessed the chemical qualities of the water and its potential for harboring and sustaining life.

Geochemical analyses suggest chemical reactions between the brine and the underlying iron-rich sediments generate nitrous oxide and molecular hydrogen. The latter, in part, may provide the energy needed to support the brine’s diverse microbial life.

Additional research is under way to analyze the abiotic, chemical interactions between the Lake Vida brine and its sediment, in addition to investigating the microbial community by using different genome sequencing approaches. The results could help explain the potential for life in other salty, cryogenic environments beyond Earth, such as purported subsurface aquifers on Mars.

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| Before Baumgartner: Five daredevils who helped science!

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Before Baumgartner: Five daredevils who helped science ~ BBC News.

Before Baumgartner: Five daredevils who helped science

Felix Baumgartner

Felix Baumgartner, who has become the first skydiver to go through the sound barrier, says the main goal of his exploit was to collect scientific data. The aim, his team insists, is to assist in the development of high-altitude parachute systems that will save lives when spacecraft are evacuated in the stratosphere.

There is a long history of people undertaking daring feats and helping science into the bargain. Here are five examples.

Captain Scott

Emperor penguin on rope lead with member of Scott's team - photo from Royal Geographical Society collection
The team spent months monitoring penguin colonies

Robert Falcon Scott is famed as the explorer who lost the race to the South Pole and who led his team to their deaths on the return journey. But his expedition also laid the foundations of modern polar science, says historian David Wilson, great-nephew of Scott’s naturalist, Edward Wilson. One of the fossils found alongside Scott’s frozen body was of a beech-like tree, Glossoptera indica, which proved that Antarctica and Australia had once been part of an ancient super-continent – and “helped us change our geological understanding of the planet” according to Wilson. Scott also collected the first Emperor penguin eggs. These disproved the theory, then current, that an embryo passed through all the stages of its species’ evolution as it developed. Scientists had expected the eggs to show the link between dinosaurs and birds – but they didn’t.

George Hedley Stainforth

Seaplanes retrace classic race route

On 29 September 1931, RAF pilot George Hedley Stainforth became the first man in the world to exceed 400mph (643Km). This broke the record set by his team earlier that year during a competition for the Schneider Trophy, in five races around the waters of the Solent, in the UK, watched by hundreds of thousands of people. The seaplane used, the Supermarine S.6, was designed by RJ Mitchell, who used it as the basis for the Hurricane, and also the Spitfire – one of the fastest fighters of its time, which became the backbone of RAF Fighter Command in World War II. The Schneider trophy was crucial to the defeat of Germany, says pilot John Russell. “If they hadn’t done that exponential development of aeronautics and engine development over the 18 years it took place, then we wouldn’t really have the aircraft like the Hurricane and Spitfire to be available by the time of the Battle of Britain.” The competition, set up by a French industrialist to encourage technical advances in aviation, ran from 1913 to 1931, with a gap during World War I. Stainforth went on to break the world record for flying upside-down – for 12 minutes.

John Paul Stapp

John Paul Stapp

In 1954, US Air Force medical researcher John Paul Stapp earned the title “the Fastest Man Alive” when he rode a rocket-powered sled to a then-world record land speed of 632mph (1.017km/h), going from a standstill to a speed faster than a 45-caliber bullet in five seconds. He then screeched to a dead stop in 1.4 seconds, sustaining a force equivalent to 46.2 times gravity. It was an experiment that tested the limits of human endurance, with the aim of making transportation safer. He suffered broken bones and detached retinas, but out of these wild rides – by December 1954, Stapp had volunteered for 29 rocket sled deceleration and windblast experiments – came improved helmets, arm and leg restraints, better aircraft seats, stronger safety harnesses and techniques for positioning the body to help absorb powerful forces.

As he had long felt that the safety measures he was developing for military aircraft should also be used for civilian automobiles, Stapp also campaigned for the installation of seat belts and other safety features in American cars. He was in the room on 9 September 1966 when US President Lyndon Johnson signed the Highway Safety Act of 1966, requiring seatbelts in all new cars sold in the US.

According to the official website of the US Air Force, Stapp is also credited with coining one of the most famous phrases in American history when he suffered injuries owing to a mistake by one of his assistants Captain Murphy. After he discovered what happened, Stapp observed that “Whatever can go wrong, will go wrong.” It’s been called “Murphy’s Law” ever since.

Yuri Gagarin

Yuri Gagarin

Russian cosmonaut Yuri Gagarin became an international celebrity on 12 April 1961, when he became the first man in space – effectively, a human guinea pig. His single orbit of Earth during a 108-minute flight – reaching an altitude of 203 miles, and a speed of 17,025mph (27,000km/h) – proved that man could endure the rigours of lift-off, re-entry, and weightlessness. It launched the era of manned spaceflight, and intensified the superpower space race that had begun with the launch of Sputnik, the first satellite, in 1957. “No-one knew what effect zero-g would have on the astronauts when they were up there. They were so concerned that he might be disorientated and disabled once he was in weightlessness,” says Reginald Turnill, the BBC’s aerospace correspondent from 1958-1975. “It was decided right from the beginning that he would not be allowed to control the spacecraft, it would all be done from the ground.” In fact, Gagarin almost lost consciousness for a different reason – a service module failed to separate from Gagarin’s capsule before he returned to earth, leading it to spin wildly and the temperature within to rise dangerously high.

Dan Martin

Dan Martin

When intensive care consultant Dan Martin climbed Everest, he reported the lowest level of oxygen in the human body ever recorded – his own. While not a daredevil as such, he is part of a team of doctors studying how the human body behaves in low-oxygen environments, in particular at high altitude, and drawing lessons for treatment of critically ill patients. “When people go into intensive care, they commonly suffer with low levels of oxygen in their blood. Some can tolerate it, some can’t. Our understanding of it is very poor,” he says. The team has already established that giving patients lots of oxygen in intensive care does not necessarily lead to better outcomes. It has also noted that Sherpas have high levels of nitric oxide in their blood, and is experimenting with raising levels of nitric oxide in the blood of patients.

Reporting by Bethan Jinkinson and Vanessa Barford.

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