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  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

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    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.
  • Massive Tornado Outbreak on Tornado Alley
    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Io...Read more

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    Massive Tornado Outbreak on Tornado Alley

    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Iowa, Illinois and Missouri. On May 20th, a massive tornado struck Moore, Oklahoma, devastating communities - destroying over 100 homes and hitting two elementary schools and a hospital - with many casualties and deaths. Our thoughts are with our friends and colleagues suffering from these storms. For more on the May 20th storms, see the NOAA Storm Prediction Center Storm Report.
  • 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.
The image shows the changes in light output over time of pulsating carbon white dwarf star.
Click on image for full size
Courtesy of K. Williams/ T. Jones/ McDonald Obs

Astronomers Discover New Type of Pulsating White Dwarf Star
News story originally written on May 1, 2008

Most of the stars in the universe, including the Sun, will end their lives as white dwarf stars. Astronomers have discovered a new type of white dwarf star, which is called a "pulsating carbon white dwarf."

A white dwarf star is what is leftover of a Sun-like star that has burned all of the fuel in its core. Recently, astronomers discovered a third type of white dwarf star. These "hot carbon white dwarfs" don't have their hydrogen and helium shells anymore, so their carbon layer is exposed. Since this discovery, astronomers have been searching to see if this new type of white dwarf star pulsates. They are interested in pulsating stars because the changes in the light a star puts out can show what goes on in its interior. This is similar to the way geologists study seismic waves from earthquakes to understand what goes on in Earth's interior. In fact, this type of star-study is called "asteroseismology."

So, astronomers names Michael H. Montgomery and Kurtis A. Williams began to study carbon white dwarfs with a telescope, looking for ones that pulsate. One of their graduate students, Steve DeGennaro, discovered a star about 800 light-years away in the constellation Ursa Major that fits the bill.

Studying these stars will shed light on how the surface of white dwarf stars lose their hydrogen and helium layers.

Last modified July 7, 2008 by Becca Hatheway.

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