Fossilised Marks Of Raindrops Reveal Ancient Atmosphere

Fossilised imprints left by raindrops in South Africa 2.7 billion years ago. Credit: Wlady Altermann/University of Pretoria

Fossil Raindrops Reveal Ancient Atmosphere -- Cosmos

BRISBANE: The fossilised marks of raindrops that fell 2.7 billion years ago in South Africa have revealed the composition of the Earth's early atmosphere.

According to a new study published in Nature today, the early Earth had an atmosphere with similar air pressure to the present day, but much higher levels of greenhouse gases. The findings, from a time when the Earth already had abundant microbial life, should improve our knowledge of what kinds of extrasolar planets might support life.

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My Comment: In short .... greenhouse gases were abundant during the time.

Did Comets Bring Life To Earth?

Photo: The combination of water, energy and amino acids – which bind together to form proteins – could have caused the first chemical reactions which are believed to be the origin of life Photo: ALAMY

Life Brought To Earth By Comets -- The Telegraph

Life on Earth may have been sparked by comets carrying with them the key ingredients for our existence, scientists claim.

NASA scientists have replicated the impact of a comet and demonstrated that amino acids, a building block of life, could have survived the intense heat and shock waves given off in the collision.

The combination of water, energy and amino acids – which bind together to form proteins – could have caused the first chemical reactions and created proteins, the researchers said.

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World's Oldest Rivers Mapped Under Huge Desert Dunes

The Simpson desert's fabled dunes block its underground water channels from remote sensing (Image: visionandimagination.com/Getty)

From New Scientist:

A network of ancient rivers and streams that once flowed beneath Australia's Simpson desert – famed for its dune fields – has been mapped in a new study. The map could lead the way to valuable minerals and water resources in this drying continent.

Michael Hutchinson and John Stein of the Australian National University in Canberra extracted data from previous ground surveys to map an ancient river system 35 metres below the surface of the desert. They think the channels are among the world's oldest at 50 million years old, when the now barren land would have been lush and well watered.

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Early Earth Embroiled In Constant Solar Storm

The larger auroral oval relative to the modern is the result of a weaker dipole magnetic field and stronger solar wind dynamic pressure. The auroral intensity is brighter due to solar wind densities many times greater than those today, and the dominant color reflects greater energies of the precipitating particles and the mildly reducing Paleoarchean atmosphere. Credit: J. Tarduno and R. Cottrell/University of Rochester

From Cosmos:

SYDNEY: A weak magnetic field and powerful solar wind stripped water from the early Earth's atmosphere 3.5 billions years ago and created stunning auroras, scientists said.

Scientists have long thought that Mars' small magnetic field left it vulnerable to the solar wind, a stream of charged particles emitted by the Sun that interacts with Earth's magnetic field and atmosphere, and forms the auroras on Earth.

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Geologists Look For Answers In Antarctica: Did Ice Exist At Equator Some 300 Million Years Ago?

From Science Daily:

Science Daily (Feb. 24, 2010) — Focusing on a controversial hypothesis that ice existed at the equator some 300 million years ago during the late Paleozoic Period, two University of Oklahoma researchers originated a project in search of clues to Earth's climate system.

"The Paleozoic Period was a rare time in history," says Gerilyn Soreghan, OU professor of geology. "Broadly speaking, it was the last time our planet experienced the type of climate system we have today and in the recent past." Soreghan believes comparing more modern systems in a range of different climates might help support her hypothesis.

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Upside-Down Answer For Deep Mystery: What Caused Earth To Hold Its Last Breath?

Volcano eruption (Reunion island, Indian Ocean).
(Credit: iStockphoto)

From Science Daily:

Science Daily (Feb. 18, 2010) — When Earth was young, it exhaled the atmosphere. During a period of intense volcanic activity, lava carried light elements from the planet's molten interior and released them into the sky. However, some light elements got trapped inside the planet. In the journal Nature, a Rice University-based team of scientists is offering a new answer to a longstanding mystery: What caused Earth to hold its last breath?

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First Breath: Earth's Billion-Year Struggle For Oxygen

The complex story of oxygen's rise (Image: Reso/Rex Features)

From The New Scientist:

OXYGEN is life. That's true not just for us: all animals and plants need oxygen to unleash the energy they scavenge from their environment. Take away oxygen and organisms cannot produce enough energy to support an active lifestyle, or even make them worth eating. Predation, an essential driver of evolutionary change, becomes impossible.

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Mediterranean Was Created In Earth's Biggest Deluge

The deluge that formed the Mediterranean. Photograph: Roger Pibernat

From The Guardian:

Catastrophic flooding caused sea levels to rise by 10 metres a day, according to new research.

The Mediterranean Sea was formed by the most spectacular flood in Earth's history when water from the Atlantic Ocean breached the mountain range joining Europe and Africa with the force of a thousand Amazon rivers, scientists say.

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Colossal Flood Created The Mediterranean Sea

Mediterranean Sea and the Strait of Gibraltar photographed by NASA. Part of Spain can be seen above and Africa, below, in the photo.

From Live Science:

The Mediterranean Sea as we know it today formed about 5.3 million years ago when Atlantic Ocean waters breached the strait of Gibraltar, sending a massive flood into the basin.

Geologists have long known that the Mediterranean became isolated from the world's oceans around 5.6 million years ago, evaporating almost completely in the hundreds of thousands of years that followed.

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Fossils Suggest An Ancient CO2-Climate Link

Mark Pink / Alamy

From Time Magazine:

Some of the best evidence linking rising carbon dioxide levels to a warmer world comes from the coldest places on earth. Samples of ancient air extracted from deep inside the Antarctic and Greenland ice caps make it clear that CO2 is scarce in the atmosphere during ice ages and relatively abundant during warmer interglacial periods — like the one we're in now.

The relationship between CO2 and climate is clear going back about 800,000 years. Before that, however, it gets murkier. That's largely because ice and air that old haven't yet been found. So scientists rely instead on indirect measurements — and these have led to a climate mystery: some episodes of past warming, including a planetary heat wave about 15 million years ago and another about 3.5 million years ago, seem to have happened without a rise in CO2. No one quite understands why. Maybe other greenhouse gases were the cause — methane, for example. Or maybe it had to do with changes in ocean circulation.

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When You Could Fling A Frisbee From Canada To Zimbabwe

Ancient basalt vein, Greenland Credit: Michael A. Hamilton

From Live Science:

Imagine flipping a Frisbee in Quebec, Canada, and seeing it land in Zimbabwe. That’s a distance of 8,000 miles now, but 2.6 billion years ago, with good wrist action, it would have been no feat at all (if only there had been Frisbees and, of course, people).

Present-day Quebec and Zimbabwe were adjacent way back then, say geologists who are using new techniques to map Earth’s early continents.

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Argentina Site Of World's Biggest Crater Field

The Barringer Crater in Arizona, USA, is one of the largest
obvious craters known on Earth. Credit: Wikipedia

From Cosmos/AFP:

BUENOS AIRES: Argentina can lay claim to the world's largest crater field: a volcanic area in Patagonia known as the Devil's Slope, according to a new study.

Covering 400 square kilometres, the Bajada del Diablo field is peppered with at least 100 depressions left by the collisions of meteorites or comets from 130,000 to 780,000 years ago, the study found.

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Flash Recovery Of Ammonoids After Most Massive Extinction Of All Time

Asteroceras, a Jurassic ammonite from England.
(Credit: Courtesy of Wikimedia Commons)

From Science Daily:

ScienceDaily (Sep. 14, 2009) — After the End-Permian extinction 252.6 million years ago, ammonoids diversified and recovered 10 to 30 times faster than previous estimates. The surprising discovery raises questions about paleontologists' understanding of the dynamics of evolution of species and the functioning of the biosphere after a mass extinction.

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Ancient Oceans Offer New Insight Into Origins Of Animal Life

In prehistoric times, Earth experienced two periods of large increases and fluctuations in the oxygen level of the atmosphere and oceans. These fluctuations also led to an explosion of multicellular organisms in the oceans, which are the predecessors for life as we know it today. (Credit: iStockphoto/Sebastian Meckelmann)

From Science Daily:

Science Daily (Sep. 10, 2009) — Analysis of a rock type found only in the world's oldest oceans has shed new light on how large animals first got a foothold on Earth.

A scientific team led by Professor Robert Frei at the University of Copenhagen in Denmark, and including scientists from Newcastle University, UK, and universities in Uruguay and Southern Denmark, have for the first time managed to plot the rise and fall of oxygen levels in the Earth's atmosphere over the last 3.8 billion years.

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Diving Deep For A Living Fossil

Light-equipped booms on Alvin illuminate the sea floor and pillow lava formations created by eruptions on the Mid-Atlantic Ridge. The Stephen Low Company and Rutgers University

From The New York Times:

For 33 years, Peter A. Rona has pursued an ancient, elusive animal, repeatedly plunging down more than two miles to the muddy seabed of the North Atlantic to search out, and if possible, pry loose his quarry.

Like Ahab, he has failed time and again. Despite access to the world’s best equipment for deep exploration, he has always come back empty-handed, the creature eluding his grip.

The animal is no white whale. And Dr. Rona is no unhinged Captain Ahab, but rather a distinguished oceanographer at Rutgers University. And he has now succeeded in making an intellectual splash with a new research report, written with a team of a dozen colleagues.

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Did an Ancient Volcano Freeze Earth?

Remnant. Toba today comprises a caldera lake, a newly arising cone (central island), and a pip-squeak of a volcanic progeny named Pusukbukit (left). Credit: NASA

From Science Now:

One fine day about 74,000 years ago, a giant volcano on Sumatra blew its top. The volcano, named Toba, may have ejected 1000 times more rock and other material than Mount St. Helens in Washington state did in 1980. In the process, it cooled the climate by at least 10°C, causing a global famine. But could the aftermath have been even worse? A new study puts to rest questions about whether Toba plunged Earth into a 1000-year deep freeze and whether an equivalent event today could jump-start a new, millennia-long ice age.

Giant volcanic eruptions such as Toba briefly cause the opposite of global warming. Although eruptions do emit greenhouse gases such as carbon dioxide, volcanoes also spew sulfur dioxide. Combined with water vapor, sulfur dioxide forms sulfate aerosols, which can spread around the globe, blocking solar radiation and chilling the air before becoming acid rain and snow.

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Was Ancient Earth A Green Planet?

From The New Scientist:

Earth's landmasses in the late Precambrian probably weren't pleasant, but at least they were green. A new analysis of limestone rocks laid down between 1 billion and 500 million years ago suggests that there was extensive plant life on land much earlier than previously thought.

The plants were only tiny mosses and liverworts, but they would have had a profound effect on the planet. They turned the hitherto barren Earth green, created the first soils and pumped oxygen into the atmosphere, laying the foundations for animals to evolve in the Cambrian explosion that started 542 million years ago.

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How Earth Got Its Oxygen

Cyanobacteria scum is now considered a nuisance, but these microbes oxygenated our planet over 2 billion years ago. Credit: Washington State Dept. of Health

From Live Science:

The first half of Earth's history was devoid of oxygen, but it was far from lifeless. There is ongoing debate over who the main biological players were in this pre-oxygen world, but researchers are digging up clues in some of the oldest sedimentary rocks on the planet.

Most scientists believe the amount of atmospheric oxygen was insignificant up until about 2.4 billion years ago when the Great Oxidation Event (GOE) occurred. This seemingly sudden jump in oxygen levels was almost certainly due to cyanobacteria – photosynthesizing microbes that exhale oxygen.

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Could Life Be 12 Billion Years Old?

From Live Science:

Much of the search for life outside of Earth's biological oasis has focused on examining the conditions on the other planets in our solar system and probing the cosmos for other Earth-like planets in distant planetary systems.

But one team of astronomers is approaching the question of life elsewhere in the universe by looking for life's potential beginning.

Aparna Venkatesan, of the University of San Francisco, and Lynn Rothschild, of NASA's Ames Research Center in Moffett Field, Calif., are using models of star formation and destruction to determine when in the roughly 13.7 billion-year history of the universe the biogenic elements – those essential to life as we know it – might have been pervasive enough to allow life to form.

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Early Rocks To Reveal Their Ages

From BBC:

A new technique has been helping scientists piece together how the Earth's continents were arranged 2.5 billion years ago.

The novel method allows scientists to recover rare minerals from rocks.

By analysing the composition of these minerals, researchers can precisely date ancient volcanic rocks for the first time.

By aligning rocks that have a similar age and orientation, the early landmasses can be pieced together.

This will aid the discovery of rocks rich in ore and oil deposits, say the scientists. The approach has already shown that Canada once bordered Zimbabwe, helping the mining industry identify new areas for exploration.

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