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  • Irish Chronicles Document Links Between Volcanoes and Weather
    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong corr...Read more

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    Irish Chronicles Document Links Between Volcanoes and Weather

    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong correlation between the occurrence of volcanic eruptions and extreme cold weather in Ireland over a 1200 year period. Data analyzed in this study cover the period from 431 to 1649, during which time up to 48 volcanic eruptions are identified in Greenland ice core records through deposition of volcanic sulfate in annual layers of ice. You can find the study (open access), published on 6 June 2013 in IOP Publishing's journal Environmental Research Letters, at http://iopscience.iop.org/1748-9326/8/2/024035/article. Find out more about how volcanoes can influence climate.
  • EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US
    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, acco...Read more

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    EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US

    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, according to the National Weather Service in Norman Oklahoma. The tornado, which remained on the ground for 40 minutes and reached 2.6 miles across (4.2 km), took the lives of 18 people including storm chasers Tim Samaras, Paul Samaras and Carl Young. For more information on the tornado, visit http://ow.ly/i/2hfDG.
  • 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.
This image shows the varied terrain of Ganymede.
Click on image for full size
NASA

Surface of Ganymede

The surface of Ganymede is halfway between that of Callisto and that of Europa. Portions of the crust are of ancient age, while other portions are relatively new.

The little white dots shown in this image are the many imact craters on Ganymede. Portions of Ganymede that are heavily cratered have not been resurfaced, indicating that they are of ancient age.

Besides the craters, the surface of Ganymede is characterized by grooved terrain, light terrain, dark terrain.

The many different kinds of terrain exhibited by Ganymede are an indication that it has experienced processes of alteration in the interior during it's evolution.

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Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Surface of Callisto

The surface of Callisto is deeply pockmarked with craters. It looks to be perhaps the most severely cratered body in the solar system. There are also very large craters to be found there. The severity...more

Surface of Europa

The picture to the left shows examples of the many amazing different surface features of Europa. Many exciting discoveries were made about Europa during the Galileo mission. The surface of Europa is unusual,...more

Ganymede Tectonism

There has been no icy volcanism on Ganymede, but it does seem that there has been a kind of tectonism, or surface motion. Examination of the surface of Ganymede reveals many kinds of faulting and fracture....more

The Grooved Terrain of Ganymede

This image shows an example of the grooved terrain of Ganymede. The image clearly shows that some things hit Ganymede and made craters after the grooves were made, because the grooves are underneath the...more

Light Terrain of Ganymede

This image shows an example of the light terrain of Ganymede. The image shows the contrast between the light terrain and the dark terrain of Ganymede. The light terrain is where the grooves of Ganymede...more

Interior of Ganymede

The diagram to the left shows a cutaway of the possible interior structure of Ganymede, based on recent measurements by the Galileo spacecraft. It shows a small core of metal, overlain with some rocky...more

Europa Ice Flows

This is an example of terrain of Europa which has been flooded by fresh water which subsequently re-froze on the surface. The edges of the flow are "lobate" meaning rounded like a puddle of water. This...more

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