Thursday, March 11, 2010

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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