Current Events

  • 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.
Icebergs in the Southern Ocean
Click on image for full size
Ute Kaden/PolarTREC

Icebergs

Icebergs are large pieces of ice floating in the ocean that have broken off of ice shelves or glaciers in Earth's polar regions. They are a part of the cryosphere.

Approximately 90% of an iceberg's mass is below the surface of the seawater. Because ice is less dense than water, a small portion of the iceberg stays above the seawater.

Icebergs can be huge. The largest ones are known as ice islands. The widest iceberg on record was 80 kilometers across. The tallest known iceberg had 168 meters of ice sticking out above the water. Since the part above the water is only 10% of its total size, imagine how much ice a large iceberg has underwater!

In 1912, a brand new ship called the RMS Titanic, collided with an iceberg in the North Atlantic and sunk on its first voyage.& Only about a quarter of the passengers and crew who were on board the Titanic survived. After this huge disaster, the International Ice Patrol was formed to track icebergs in the North Atlantic, ensuring that other ships did not meet a similar fate. The Patrol first monitored icebergs from ships. Later, in the 1930s, airplanes were used to keep track of icebergs. Today, icebergs can be tracked using satellites. In an average year, nearly 500 icebergs pass through the shipping routes in the North Atlantic Ocean. The Patrol warns sailors when the danger of icebergs is high.

As they travel from the polar areas where they form into warmer waters, the ice melts, and icebergs become smaller.

Last modified April 18, 2007 by Lisa Gardiner.

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