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TOPIC: The Earth


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The once-mysterious planetary hum of the Earth is getting put to use by scientists mapping the planets interior.
Ocean wave interactions, primarily along the Pacific coast of North America, generate a vibration with a frequency of about 10 millihertz, the background buzz of the globe.
As the hum moves through the Earths crust, it speeds up and slows down in response to the different materials it moves through. Scientists know from many experiments tracking how earthquake waves move through the Earth that colder, denser materials tend to speed waves up and hotter ones tend to slow them down. By looking at those changes, a team led by Kiwamu Nishida of the University of Tokyo generated a map of the interior of the planet, as reported Thursday in the journal Science.


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Five billion years ago, a massive asteroid crashed into the young earth. The impact was so great that it tilted the entire planet at an angle of 23.5° .
But far from being a catastrophe, this cosmic accident was crucial to creating life and the world as we know it today.
Without the earth's tilt, we wouldn't have such a spectacular variety of landscapes, or such extremes of hot and cold. We wouldn't have the changing seasons. And most importantly, we wouldn't have the perfect conditions for life.

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Could Earth Be Swallowed by the Dying Sun?
Scientists have debated for years what will happen to our planet when the sun's fusion furnace begins to run out of fuel and swell into a red giant a few billion years from now. The most recent simulations suggest that Earth will end up being swallowed by the dying sun.
The impending doom is more dire than any fictional villain could ever wish upon a world. Yet the planet need not perish if future civilizations can somehow move Earth out beyond the danger zone. Barring that, a clever escape plan might prove useful.

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The most complete terrain map of the Earth's surface has been published.
The data, comprising 1.3 million images, come from a collaboration between the US space agency Nasa and the Japanese trade ministry.
The images were taken by Japan's Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster) aboard the Terra satellite.

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Question: What would life on Earth be like if there were no Moon?
Answer: So different maybe there'd be no intelligent life here to pose the question, says Penn State University geoscientist James Kasting.

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Earth's mantle
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By using a super-computer to virtually squeeze and heat iron-bearing minerals under conditions that would have existed when the Earth crystallised from an ocean of magma to its solid form 4.5 billion years ago, two UC Davis geochemists have produced the first picture of how different isotopes of iron were initially distributed in the solid Earth.
The discovery could usher in a wave of investigations into the evolution of Earth's mantle, a layer of material about 1,800 miles deep that extends from just beneath the planet's thin crust to its metallic core.

"Now that we have some idea of how these isotopes of iron were originally distributed on Earth. We should be able to use the isotopes to trace the inner workings of Earth's engine" - study senior author James Rustad, a chancellor's fellow and professor of geology.

A paper describing the study by Rustad and co-author Qing-zhu Yin, an associate professor of geology, was posted online by the journal Nature Geoscience on Sunday, June 14, in advance of print publication in July.

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Earth's atmosphere
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Astronomers have seen what the Earth's atmosphere might look like from outer space by using the Moon as a giant mirror. Sunlight that bounced back from the Moon carried a fingerprint of the Earth's atmosphere that could help astronomers determine if the extrasolar planets they're finding harbour life.
The astronomers, at Spain's Institute of Astrophysics of the Canary Islands, made their observations on 16 August 2008 during a lunar eclipse - in which the Moon moves into Earth's shadow. Even when the Moon is totally eclipsed by Earth, it is still bathed in a dim red light - from sunlight that has been bent as it passes through the edge of Earth's atmosphere. Using Earth-based telescopes, the astronomers detected some of this light after it bounced back from the Moon, and captured a 'transmission spectrum' of the light that had passed through Earth's atmospheric halo.

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A storm of meteorites that pounded Earth and Mars four billion years ago may have made the planets warmer and wetter.
Researchers superheated younger space rocks to measure the gases that would have been shed as meteorites entered fledgling atmospheres during the storm.
There would have been enough to create warmer and wetter planets more amenable to life, they say.
The work is published in Geochimica et Cosmochimica Acta.

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