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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
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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.
This picture shows a bright Leonid meteor that was seen in November 1998. The light from this meteor lit up some clouds, creating this beautiful photo opportunity!
Click on image for full size
Courtesy of Lorenzo Lovato of Imola, Italy

Leonid Meteor Shower

The Leonid meteor shower is one of several major meteor showers that occur on roughly the same date each year. The Leonids typically "peak" (are at their greatest level of activity) in mid to late November. The Leonid shower's name is derived from the fact that its meteors appear to fan out from a point in sky, called the shower's "radiant", which lies within the constellation Leo.

In 2009, the Leonid shower is expected to peak on the night of Tuesday, November 17th. Since there will be a New Moon around this time, this year should be a good year to spot some Leonids. A bright Moon makes it hard to see meteors.

As is the case with most meteor showers, it will be possible to see Leonid meteors for several days before and after the peak on the 17th. In fact, it is sometimes possible to see some Leonids as early as November 14th and to continue to spot a few up to November 21st. At this shower's peak observers may be able to see as many as 100 "shooting stars" per hour under dark skies (away from city lights). However, the Leonids, as compared to other meteor showers, present a highly variable celestial show. The number of meteors visible at the shower's peak can change quite a bit from year to year in an unpredictable fashion.

The Leonids are actually bits of dust that have been shed over the centuries by a comet named comet 55P/Tempel-Tuttle! The dust, which spews forth from the comet's nucleus each time it passes near the Sun, gradually spreads out over the entire orbit of the comet. If Earth's orbit happens to cross the comet's orbit, the swarm of debris scattered along the comet's orbit is visible to us as a meteor shower. Since the Earth crosses the comet's orbit at the same time each year, each meteor shower is predictably visible at the same time of year, year after year.

Most meteors in a shower are quite small, about the size of a grain of sand. Leonids are among the fastest-moving meteors. These meteors typically strike our atmosphere while traveling at speeds around 72 kilometers per second (about 161,000 mph). Because of their high speeds, Leonids typically leave long, glowing trails in the sky.

Last modified October 20, 2009 by Randy Russell.

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