Tag Archives: thorium

Search for Life Suggests Solar Systems More Habitable than Ours

SAN FRANCISCO — Scattered around the Milky Way are stars that resemble our own sun—but a new study is finding that any planets orbiting those stars may very well be hotter and more dynamic than Earth.

That’s because the interiors of any terrestrial planets in these systems are likely warmer than Earth—up to 25 percent warmer, which would make them more geologically active and more likely to retain enough liquid water to support life, at least in its microbial form.

The preliminary finding comes from geologists and astronomers at Ohio State University who have teamed up to search for alien life in a new way. (more…)

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Grand Canyon as Old as the Dinosaurs, Suggests New Study Led by CU-Boulder

An analysis of mineral grains from the bottom of the western Grand Canyon indicates it was largely carved out by about 70 million years ago — a time when dinosaurs were around and may have even peeked over the rim, says a study led by the University of Colorado Boulder.

The new research pushes back the conventionally accepted date for the formation of the Grand Canyon in Arizona by more than 60 million years, said CU-Boulder Assistant Professor Rebecca Flowers. The team used a dating method that exploits the radioactive decay of uranium and thorium atoms to helium atoms in a phosphate mineral known as apatite, said Flowers, a faculty member in CU-Boulder’s geological sciences department. (more…)

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Where the Earth’s Heat Comes From

*Berkeley Lab scientists join their KamLAND colleagues to measure the radioactive sources of Earth’s heat flow*

What spreads the sea floors and moves the continents? What melts iron in the outer core and enables the Earth’s magnetic field? Heat. Geologists have used temperature measurements from more than 20,000 boreholes around the world to estimate that some 44 terawatts (44 trillion watts) of heat continually flow from Earth’s interior into space. Where does it come from?

Radioactive decay of uranium, thorium, and potassium in Earth’s crust and mantle is a principal source, and in 2005 scientists in the KamLAND collaboration, based in Japan, first showed that there was a way to measure the contribution directly. The trick was to catch what KamLAND dubbed geoneutrinos – more precisely, geo-antineutrinos – emitted when radioactive isotopes decay. (KamLAND stands for Kamioka Liquid-scintillator Antineutrino Detector.) (more…)

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Arctic Rocks Offer New Glimpse of Primitive Earth

Scientists have discovered a new window into the Earth’s violent past. Geochemical evidence from volcanic rocks collected on Baffin Island in the Canadian Arctic suggests that beneath it lies a region of the Earth’s mantle that has largely escaped the billions of years of melting and geological churning that has affected the rest of the planet. Researchers believe the discovery offers clues to the early chemical evolution of the Earth.

(more…)

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