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  • Kansas Legislator Proposes Bill to Outlaw Sustainability Education
    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of ...Read more

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    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.
  • Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows
    Scientists have determined the temperature near the Earth’s center to be 6000 degrees Celsius, 1000 ...Read more

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    Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows

    Scientists have determined the temperature near the Earth’s center to be 6000 degrees Celsius, 1000 degrees hotter than in a previous experiment run 20 years ago. These measurements confirm geophysical models that the temperature difference between the solid core and the mantle above, must be at least 1500 degrees to explain why the Earth has a magnetic field. For more information about this study, see the press release from the European Synchrotron Radiation Facility.
  • Ocean Volcanic Rocks Contain Samples of Recycled Crust
    Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials fr...Read more

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    Ocean Volcanic Rocks Contain Samples of Recycled Crust

    Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials from the early Earth’s crust. But decisive evidence for this phenomenon has proven elusive. New research from a team including Carnegie’s Erik Hauri demonstrates that oceanic volcanic rocks contain samples of recycled crust dating back to the Archean era 2.5 billion years ago. Their work is published in Nature. Oceanic crust sinks into the Earth’s mantle at so-called subduction zones, where two plates come together. Much of what happens to the crust during this journey is unknown. Model-dependent studies for how long subducted material can exist in the mantle are uncertain and evidence of very old crust returning to Earth’s surface via upwellings of magma has not been found until now. For more information about these results, see the press release from the Carnegie Institution.
These two images show Triton's South Pole. The nitrogen ice polar cap is the light pink area along the bottom and lower left parts of the lower image.
Click on image for full size
Images courtesy of NASA/JPL/USGS.

The Poles of Triton

Triton is by far the largest moon of Neptune, and is one of the most unusual large moons in the Solar System. The poles of Triton are especially interesting.

Triton has a frozen polar cap with ice geysers. This frigid moon has a very high surface albedo (it is covered with bright, shiny ices), especially at the South Pole. The pole is topped with a cap of nitrogen and methane ices. Scientists have spotted darker smears near Triton's South Pole, which they believe are surface deposits of materials downwind of cryovolcanoes (ice geysers or ice volcanoes). This makes Triton one of only four Solar System bodies on which active volcanism has been observed; the other three are Earth, Jupiter's moon Io, and Saturn's moon Enceladus. Astronomers suspect that Triton's North Pole is also covered by an ice cap; however, the moon's northern hemisphere has never been imaged in detail.

Thanks to an odd mix of orbital geometries of both Triton and its "parent" planet Neptune, Triton's poles spend most of their time in either perpetual darkness or perpetual light. Triton may have been a Kuiper Belt Object that was captured into orbit by Neptune's gravity in the distant past. The moon's orbit is tilted by a large amount away from Neptune's equator. Triton's odd orbit combined with Neptune's axial tilt and long orbital period (more than 164 Earth years) make for very, very long seasons at the moon's poles. Triton's poles alternate between 80+ years of perpetual summertime daylight and 80+ years of winter darkness.

Last modified April 21, 2009 by Randy Russell.

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