University of California, Santa Barbara | 2015 July 20
Geochemist Matthew Jackson argues that the abundance of certain elements in the Earth dictate whether plate tectonics can happen
[img3="NASA Kepler's Hall of Fame (Jan 2015): (Credits: NASA)Planet Earth is situated in what astronomers call the Goldilocks Zone — a sweet spot in a solar system where a planet’s surface temperature is neither too hot nor too cold. An ideal distance from a home star — in Earth’s case, the sun – this habitable zone, as it is also known, creates optimal conditions that prevent water from freezing and generating a global icehouse or evaporating into space and creating a runaway greenhouse.
Of the more than 1,000 verified planets found by NASA's Kepler Space Telescope,
eight are less than twice Earth-size and in their stars' habitable zone. "]http://www.nasa.gov/sites/default/files ... e-full.jpg[/img3][hr][/hr]
However, a new theory by UC Santa Barbara geochemist Matthew Jackson posits that the bulk composition of a planet may also play a critical role in determining the planet’s tectonic and climatic regimes and therefore its habitability. In a paper published today in Nature Geoscience, Jackson, an associate professor in UCSB’s Department of Earth Science, and Mark Jellinek of the University of British Columbia discuss their research.
According to Jackson, plate tectonics is a manifestation of the Earth trying to cool itself. Cold plates sink into the Earth and absorb heat, while volcanoes release heat where plates are spreading apart and forming. “Whether or not plate tectonics can happen actually depends on whether or not the Earth is too hot or too cold,” he said. “If it’s too hot, plate tectonics seizes up and if it’s too cold, it freezes up.” ...
Connections between the bulk composition, geodynamics and habitability of Earth - A. M. Jellinek, M. G. Jackson
- Nature Geoscience (online 20 July 2015) DOI: 10.1038/ngeo2488