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Source: University of Chicago Date: February 5, 2007 Ancient Rocks Show How Young Earth Avoided Becoming Giant Snowball Science Daily — A greenhouse gas that has become the bane of modern society may have saved Earth from completely freezing over early in the planet's history, according to the first detailed laboratory analysis of the world's oldest sedimentary rocks. A rock from a banded iron formation in northern Quebec, Canada. The bands vary in thickness from approximately 10 microns (less than the width of a human hair), to 10 meters (30 feet). This sample is measures a few inches across. At...

The world's oldest water, which is locked deep within the Earth's crust, is present at a far greater volume than was thought, scientists report. The liquid, some of which is billions of years old, is found many kilometres beneath the ground. Researchers estimate there is about 11m cubic kilometres (2.5m cu miles) of it - more water than all the world's rivers, swamps and lakes put together. The study was presented at the American Geophysical Union Fall Meeting. It has also been published in the journal Nature. The team found that the water was reacting with the rock to release...

Using the oldest fossil micrometeorites -- space dust -- ever found, Monash University-led research has made a surprising discovery about the chemistry of Earth's atmosphere 2.7 billion years ago. The findings of a new study published today in the journal Nature -- led by Dr Andrew Tomkins and a team from the School of Earth, Atmosphere and Environment at Monash, along with scientists from the Australian Synchrotron and Imperial College, London -- challenge the accepted view that Earth's ancient atmosphere was oxygen-poor. The findings indicate instead that the ancient Earth's upper atmosphere contained about the same amount of oxygen as...

Using primitive meteorites called chondrites as their models, earth and planetary scientists at Washington University in St. Louis have performed outgassing calculations and shown that the early Earth's atmosphere was a reducing one, chock full of methane, ammonia, hydrogen and water vapor. In making this discovery Bruce Fegley, Ph.D., Washington University professor of earth and planetary sciences in Arts & Sciences, and Laura Schaefer, laboratory assistant, reinvigorate one of the most famous and controversial theories on the origins of life, the 1953 Miller-Urey experiment, which yielded organic compounds necessary to evolve organisms. Chondrites are relatively unaltered samples of material from...

Most scientists have long assumed that life on Earth is a homegrown phenomenon. According to the conventional hypothesis, the earliest living cells emerged as a result of chemical evolution on our planet billions of years ago in a process called abiogenesis. The alternative possibility--that living cells or their precursors arrived from space--strikes many people as science fiction. Developments over the past decade, however, have given new credibility to the idea that Earth's biosphere could have arisen from an extraterrestrial seed. Planetary scientists have learned that early in its history our solar system could have included many worlds with liquid water,...

Evidence that water came to Earth during its formation from cosmic dust, rather than following later in asteroids, has been shown by a group of international scientists. The origin of the abundant levels of water on Earth has long been debated with the main differences in the theories being the nature of the material that carries the water, and whether the water came during or after planet formation. Now, Nora de Leeuw at University College London, UK, and colleagues have used molecular-level calculations to prove that dissociative chemisorption of water onto the surface of olivine rich minerals, such as forsterite,...

The Mars rover Opportunity's examination of Martian rocks last week provided the first convincing evidence that our neighbour world was once "awash" in water, as one NASA scientist described it. But where did the water come from? And why does Mars have no liquid water now, while Earth apparently has been covered with the stuff for 4 billion years? Scientists are just beginning to piece the story together, and it goes right back to the beginning. Mars, like Earth, was formed from dusty and rocky debris left over after the sun was born 4.57 billion years ago. Initially, there were...

Comet Hartley 2 contains water more like that found on Earth than prior comets seem to have, researchers say. A study using the Herschel space telescope aimed to measure the quantity of deuterium, a rare type of hydrogen, present in the comet's water. The comet had just half the amount of deuterium seen in comets. The result, published in Nature, hints at the idea that much of the Earth's water could have initially came from cometary impacts. Just a few million years after its formation, the early Earth was rocky and dry; something must have brought the water that covers...

Scientists have long believed that comets and, or a type of very primitive meteorite called carbonaceous chondrites were the sources of early Earth's volatile elements -- which include hydrogen, nitrogen, and carbon -- and possibly organic material, too. Understanding where these volatiles came from is crucial for determining the origins of both water and life on the planet. New research led by Carnegie's Conel Alexander focuses on frozen water that was distributed throughout much of the early Solar System, but probably not in the materials that aggregated to initially form Earth... It has been suggested that both comets and carbonaceous...

Enlarge Image Ironclad? Analyses of rocks in an ancient Greenland formation debunk the idea of an early greenhouse Earth. Credit: M. Rosing Dial back the clock nearly 4 billion years, to a time called the Archean, and the sun would appear about 30% dimmer than it is now. That's a problem: It couldn't have warmed Earth enough to keep the seas from becoming permanent ice sheets. Yet overwhelming geological evidence indicates that liquid water has existed on our planet since the seas formed more than 4 billion years ago, even during the deepest ice ages. What could have provided...

A new chemical analysis of lunar material collected by Apollo astronauts in the 1970s conflicts with the widely held theory that a giant collision between Earth and a Mars-sized object gave birth to the moon 4.5 billion years ago.