Current Events

  • 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.

Mercury Transit on November 8, 2006
News story originally written on November 6, 2006

The planet Mercury will cross in front of the Sun on Wednesday, November 8, 2006. Astronomers call the event a transit. A transit is like a solar eclipse. However, a transit occurs when a planet, instead of Earth's Moon, passes between the Sun and Earth. Planets are much further away than the Moon, so the planet does not completely cover the Sun during a transit like the Moon does during an eclipse.

Transits of Mercury happen about once every seven years on average. There will be 14 transits of Mercury this century. This one was the second. The last transit of Mercury before this one was on May 7, 2003. The next won't be until May 9, 2016.

Only two planets ever transit the Sun as viewed from Earth. The two planets are Mercury and Venus. All of the other planets orbit the Sun further from Earth and never pass between Earth and the Sun.

Transits of Venus are much rarer than transits of Mercury. Venus transits happen only twice per century. Maybe you saw the one on June 8, 2004. If not, the next transit of Venus is coming along in just a few years on June 6, 2012! Astronomers in the 1700's used transits of Venus to make the first good measurements of the distance between Earth and the Sun. They did that by carefully measuring the time of the transit from different places on Earth.

Last modified November 6, 2006 by Randy Russell.

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Mercury Transit on May 7, 2003

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Mercury Transit on November 8, 2006

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The Spring 2011 issue of The Earth Scientist is focused on modernizing seismology education. Thanks to IRIS, you can download this issue for free as a pdf. Print copies are available in our online store.

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