Projects: Target Earth
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Media contact:
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Recent Target Earth Press Releases:
June 26, 2008: Target Earth: How Prepared are We?
Pasadena, CA, —It exploded over Siberia – this object from space – and leveled 2,000 square kilometers of forest, flattening pine trees like matchsticks. June 30 marks the 100th anniversary of the Tunguska event, the day in 1908 when an asteroid or comet entered Earth’s atmosphere and, in effect, fired an astronomical warning shot across our bow. How prepared is Earth today to avoid disaster from the skies? Read more>>
Images:
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The Tunguska Air Blast, June 30, 2008
The hot lower vapor, still surging forward, has just cooled from the
white hot intensity which caused the nearby flash fires. The higher
portions of the debris cloud are rising from the bolide path, and
parts of the cloud are rising in the middle and just starting to at
the end, corrisponding to locations of multiple bursts. The
simulation by Mark Boslough were inspiration on the possible dynamics
of the shock wave and plume.
Credit: (c) Don Davis. For a high resolution file contact the artist:
dondavis@thegrid.net
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Fallen Forest at Tunguska
On June 30, 1908, an asteroid exploded in the atmosphere above Tunguska in central Siberia. This image of the devastation was taken by Leonid Kulik's expedition to the site 19 years later. Kulik estimated that 2150 square kilometers (830 square miles) of forest were flattened by the event, or a circle of 25 kilometers around the epicenter.
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Felled trees at Tunguska
Trees felled by the 1908 impact as seen today.
Credit: Tunguska Page of Bologna University: http://www-th.bo.infn.it/tunguska/
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Tunguska, Siberia
A map of Russia showing the location of the Tunguska impact.
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Tunguska asteroid simulation
Computer simulation of the Tunguska impact by Mark Boslough and David Crawford of the Sandia National Laboratories in New Mexico. Note the firey wake behind the asteroid, the point of explosion when the fireball is formed, and the fireball continuing towards the surface. The bluish outline marks the shockwave, which caused most of the devastation in Tunguska.
Credit: M. Boslough/Sandia National Laboratories
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Nuclear devastation
Hiroshima, August 1945. The city was destroyed by a nuclear detonation of around 15 kilotons at a height of 580 meters. For comparison, recent studies suggest that the Tunguska impact was 300 times more powerful (3 to 5 megatons) and took place at an altitude of around 12 kilometers.
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A Tunguska impact on Los Angeles
The shaded area shows the area devastated by the Tunguska event, overlaid on a map of Los Angeles. It shows that a similar impact over LA would have destroyed a large portion the city, possibly killing millions.
Credit: Albert Glassman |
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