Comet May Not Have Rocked Stone Age World

From Live Science:

While most scientists agree that a large object from space likely crashed into Earth and led to the eventual demise of the dinosaurs, a new study takes aim at theories that suggest similar events spelled bad news for large animals and Stone Age hunters nearly 13,000 years ago.

For about three years, scientists have debated over what caused drastic climate changes and gaps in the archaeological record at the end of the Pleistocene Epoch, a period of time spanning from about 1.8 million to 11,500 years ago.

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Life On Earth May Have Had An Icy Start

From The Danger Room:

Tracks in ice could have served as a safe environment — much like a cell — for the first life on Earth to replicate and evolve.

A new study adds plausibility to the ‘RNA World’ hypothesis that argues life began with a single stranded molecule capable of self-replication.

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Dawn Of The Anthropocene Epoch? Earth Has Entered New Age of Geological Time, Experts Say

Scientists contend that recent human activity, including stunning population growth, sprawling megacities and increased use of fossil fuels, have changed the planet to such an extent that we are entering what they call the Anthropocene (New Man) Epoch. (Credit: iStockphoto)

From Science Daily:

ScienceDaily (Mar. 26, 2010) — Geologists from the University of Leicester are among four scientists- including a Nobel prize-winner -- who suggest that Earth has entered a new age of geological time.

The Age of Aquarius? Not quite -- It's the Anthropocene Epoch, say the scientists writing in the journal Environmental Science & Technology.

And they add that the dawning of this new epoch may include the sixth largest mass extinction in Earth's history.

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Iceberg Forensics: Predicting The Planet's Future With Antarctic Ice

From Popular Mechanics:

In the last million years, the North American ice sheet has formed and completely melted about 10 times. Ice is melting once again—simultaneously, across the globe—and the science research vessel and drilling ship JOIDES Resolution has been seeking out clues to how ice sheets may respond to a warming climate. Onboard in Antarctica, Trevor Williams reports on the role that ice has played throughout geologic history and what a new iceberg in the Southern Ocean can tell us about the future for the planet.

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Ice Once Covered The Equator

Two ideas exist on the progression of glaciation on Earth from 716.5 to 630 million years ago. Current evidence suggests the top version: a dynamic snowball Earth in which at least two long-lived glaciations happened during which communication between the ocean and the atmosphere was cut off. In this scenario, as CO2 built up, a hot-house effect ensued resulting in an ice-free planet at 670 and 630 million years ago. Credit: Zina Deretsky, National Science Foundation

From Live Science:

Sea ice may have covered the Earth's surface all the way to the equator hundreds of millions of years ago, a new study finds, adding more evidence to the theory that a "snowball Earth" once existed.

The finding, detailed in the March 5 issue of the journal Science, also has implications for the survival and evolution of life on Earth through this bitter ice age.

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Models of Sea Level Change During Ice-Age Cycles Challenged

Data researchers collected on speleothem encrustations, a type of mineral deposit, in coastal caves on the Mediterranean island of Mallorca indicate that sea level was about one meter above present-day levels around 81,000 years ago. (Credit: Image courtesy of University of Iowa)

From Science Daily:

Science Daily (Feb. 12, 2010) — Theories about the rates of ice accumulation and melting during the Quaternary Period -- the time interval ranging from 2.6 million years ago to the present -- may need to be revised, thanks to research findings published by a University of Iowa researcher and his colleagues in the Feb. 12 issue of the journal Science.

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How Earth Survived Its Birth: New Simulation Reveals Planet Migration Prevents Plunge Into Sun

New simulations show that variations in temperature can lead to regions of outward and inward migration that safely trap planets on orbits around their sun. (Credit: iStockphoto/Kirill Putchenko)

From Live Science:

Science Daily (Jan. 8, 2010) — For the last 20 years, the best models of planet formation -- or how planets grow from dust in a gas disk -- have contradicted the very existence of Earth. These models assumed locally constant temperatures within a disk, and the planets plunge into the Sun. Now, new simulations from researchers at the American Museum of Natural History and the University of Cambridge show that variations in temperature can lead to regions of outward and inward migration that safely trap planets on orbits.

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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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Like Hungry Teen, Life On Earth Had Big Growth Spurts

The Sequoia tree, the largest living thing on Earth, dwarfs humans and our ancient one-celled ancestors. Jane Wooldridge/Miami Herald/MCT

From McClatchy News:

WASHINGTON — Twice in the Earth's history, living creatures underwent astonishing growth spurts, and each time, new organisms emerged that were a million times larger than anything that had existed before.

Scientists say that's the way life on our planet expanded from tiny single-celled microbes billions of years ago to the ponderous whales and lofty sequoia trees that are today's biggest living things.

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The World's Best Impact Craters

Also known as the "eye of Quebec", Manicougan Crater in Canada is one the Earth's oldest known impact craters, and is about 200 million years old. Today it contains a 70-kilometre hydroelectric reservoir along its edge. The island in the centre of the crater was formed by post-impact uplift of the land. Also visible in the bottom left-hand corner is the fin of the space shuttle from which this image was taken.(Image: LSTS-9 Crew/NASA/GSFC)

From The New Scientist:

Approximately 150 impact craters are known on Earth, but most are severely eroded or hidden beneath tonnes of rock. Still, a few spectacular examples are visible with aerial photography, satellites or instruments that can peek beneath the surface.

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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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Hole In The Earth

The Aorounga crater is spproximately 345–370 million years old based on the age of the sedimentary rocks deformed by the impact.

From Live Science:

A meteorite that rocked the Sahara desert over 300 million years ago left behind quite a scar that's been photographed before.

New satellite images released by NASA this week provide a closer view of the Aorounga Impact Crater in north-central Chad, one of the best preserved impact structures in the world.

The crater measures 10 miles (17 kilometers) across with a peak that is surrounded by a small sand-filled trough. This feature is surrounded by an even larger circular trough. Winds at the site blow from the northeast and sand dunes formed between the ridges are actively migrating to the southwest. Measuring 10 miles (17 kilometers) across,

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Ancient Ice Age, Once Regarded As Brief 'Blip' Found To Have Lasted For 30 Million Years

From Science Daily:

ScienceDaily (June 17, 2009) — Geologists at the University of Leicester have shown that an ancient Ice Age, once regarded as a brief 'blip', in fact lasted for 30 million years.

Their research suggests that during this ancient Ice Age, global warming was curbed through the burial of organic carbon that eventually lead to the formation of oil – including the 'hot shales' of north Africa and Arabia which constitute the world's most productive oil source rock.

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Space Rock Yields Carbon Bounty

From The BBC:

Formic acid, a molecule implicated in the origins of life, has been found at record levels on a meteorite that fell into a Canadian lake in 2000.

Cold temperatures on Tagish Lake prevented the volatile chemical from dissipating quickly.

An analysis showed four times more formic acid in the fragments than has been recorded on previous meteorites.

The researchers told a meeting of the American Geophysical Union that the formic acid was extraterrestrial.

Formic acid is one of a group of compounds dubbed "organics", because they are rich in carbon.

"We are lucky that the meteorite was untouched by humans hands, avoiding contamination by organic compounds that we have on our fingers," said Dr Christopher Herd, the curator of the University of Alberta's meteorite collection.

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Massive Asteroid Bombardment May Have Helped Life To THRIVE On Earth

Asteroids bombarded Earth 3.9billion years ago but may not have wiped out all life. In fact some bacteria may have thrived

From The Daily Mail:

A heavy bombardment by asteroids the size of Ireland actually helped life to THRIVE on Earth 3.9billion years ago, scientists have suggested.

Many experts had thought the violent pelting by massive asteroids during the period known as the Late Heavy Bombardment would have melted the Earth's crust and vaporized any life on the planet.

But new three-dimensional computer models developed by a team at the University of Colorado at Boulder shows much of Earth's crust, and the microbes living on it, could have survived and may have even flourished in the harsh conditions.

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Volcanic Shutdown May Have Led To 'Snowball Earth'

Photo: Early in our planet's history, volcanoes stopped spewing out lava for around 250 million years (Image: Denis Hallinan / Alamy)

From New Scientist:

A 250-million-year shutdown of volcanic activity which is thought to have occurred early in Earth's history may be what turned the planet into a glacier-covered snowball. It could also have helped give rise to our oxygen-rich atmosphere.

Previous studies have noted that very little volcanic material has been dated to between 2.45 and 2.2 billion years ago, but it was widely assumed the gap would vanish as more samples were dated. Now an analysis of thousands of zircon minerals collected from all seven continents indicates that the gap may be real after all. Zircons provide a record of past volcanic activity, as the date they were formed can be calculated from the radioactive isotopes they contain.

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Oldest Surface On Earth Discovered

This natural "desert pavement" in Israel's Negev Desert has been dated to about 1.8 million years old, the olest known vast expanse of surface area on the planet. Credit: Ari Matmon, Hebrew University

From Live Science:

Earth's surface is mostly fresh in geologic terms.

Weathering — wind and water, freezing and thawing — takes its toll, and longer-term changes caused by volcanic activity and sliding crustal plates, known as tectonic activity, fold today's ground into tomorrow's interior.

The constant makeover of the planet is typically fastest in the mountains, slower in the tectonically inactive deserts.

A new study of ancient "desert pavement" in Israel's Negev Desert finds a vast region that's been sitting there exposed, pretty much as-is, for about 1.8 million years, according to Ari Matmon and colleagues at Hebrew University of Jerusalem.

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Ancient Tsunami 'Hit New York'

From The BBC:

A huge wave crashed into the New York City region 2,300 years ago, dumping sediment and shells across Long Island and New Jersey and casting wood debris far up the Hudson River.

The scenario, proposed by scientists, is undergoing further examination to verify radiocarbon dates and to rule out other causes of the upheaval.

Sedimentary deposits from more than 20 cores in New York and New Jersey indicate that some sort of violent force swept the Northeast coastal region in 300BC.

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Titanium Reveals Explosive Origins Of The Solar System

Photo: The same ratio of two varieties of titanium has been found in a range of meteorites, hinting that the cloud of gas and dust that formed the solar system was well-mixed before the first solids formed (Illustration: NASA)

From New Scientist:

The solar system emerged from a well-blended soup of dust and gas despite being cobbled together from the remains of multiple exploded stars, new meteorite measurements suggest.

Meteorites form a fossil record of the conditions that existed when they formed. By looking at the chemical makeup of some rocks, evidence has mounted in recent years that sun and the rest of the solar system formed from a cloud of debris blasted away from a number of supernovae.

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When Life As We Know It Became Possible On Earth

From The Independent:

The mystery of how our planet's atmosphere became rich in oxygen has finally been solved.

It was one of the most important changes to have happened to the Earth's atmosphere and it was the reason why today we can breathe life-giving oxygen. And yet the Great Oxidation Event has remained a mystery – until now.

Without oxygen, life on Earth would not exist as we know it. It has provided the supercharged air that has fuelled an explosion in the diversity and size of all living organisms, from the smallest shrimp to the biggest dinosaur.

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