Many folks would like to see us back on the Moon and developing its resources.

Wednesday, December 26, 2012

All-Clear' Asteroid Will Miss Earth in 2040


All-Clear' Asteroid Will Miss Earth in 2040
Posted Saturday, December 22, 2012

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Using the Gemini North telescope on Mauna Kea, Hawaii, a team of astronomers from the University of Hawaii's Institute for Astronomy (IfA) have confirmed that the chance of asteroid 2011 AG5 impacting Earth in 2040 is no longer a significant risk -- prompting a collective sigh-of-relief. Previously, scientists estimated that the risk of this 140-meter-diameter (about the length of two American football fields) asteroid colliding with the Earth was as high as one in 500.
If this object were to collide with the Earth it would have released about 100 megatons of energy, several thousand times more powerful than the atomic bombs that ended World-War II. Statistically, a body of this size could impact the Earth on average every 10,000 years.

The observations, using the Gemini Multi-Object Spectrograph (and imager), were especially challenging said team-member Richard Wainscoat. "These were extremely difficult observations of a very faint object," he said. "We were surprised by how easily the Gemini telescope was able to recover such a faint asteroid so low in the sky." The Gemini observations were made on October 20, 21, and 27, 2012.

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No longer a significant risk so why me worry.  In 2040 I will be 103yrs. 
How about you - good time or a bad time - ???
- LRK -

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The orbit of asteroid 2011 AG5 carries it beyond the orbit of Mars and as close to the sun as halfway between Earth and Venus.

The orbit of asteroid 2011 AG5 carries it beyond the orbit of Mars and as close to the sun as halfway between Earth and Venus. Image credit: NASA/JPL/Caltech/NEOPO 
› Larger image

February 28, 2012

Asteroid 2011 AG5 has been receiving a lot of attention lately because of a very unlikely scenario which would place it on an Earth-interception course 28 years from now.  Here is a scientific reality check of this relatively nondescript space rock which is currently ranked a "1" on the 1 to 10 Torino Impact Hazard Scale

As of Feb. 26, 2012, asteroid 2011 AG5 is one of 8,744 near-Earth objects that have been discovered.  It is approximately 460 feet (140 meters) in size and its orbit carries it as far out as beyond Mars' orbit and as close to the sun as halfway between Earth and Venus.  It was discovered on Jan. 8, 2011, by astronomers using a 60-inch Cassegrain reflector telescope located at the summit of Mount Lemmon in the Catalina Mountains north of Tucson, Arizona.
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"In September 2013, we have the opportunity to make additional observations of 2011 AG5 when it comes within 91 million miles (147 million kilometers) of Earth," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "It will be an opportunity to observe this space rock and further refine its orbit. Because of the extreme rarity of an impact by a near-Earth asteroid of this size, I fully expect we will be able to significantly reduce or rule out entirely any impact probability for the foreseeable future." Even better observations will be possible in late 2015.
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When you look at the Moon you can see what look like impact craters.  When you look around on Earth it is often hard to know that you may be living in the middle of a large impact crater because the trees and vegetation may hide the view of the hills which might well be part of the crater rim.
- LRK -

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List of impact craters on Earth

This list of impact craters on Earth includes confirmed impact craters as listed in the Earth Impact Database.
Confirmed impact craters listed by size

Only the largest craters (20 km or more diameter) are listed below; the rest are listed by geographical region on subsidiary lists. These features were caused by the collision of large meteorites or comets with the Earth. For eroded or buried craters the stated diameter typically refers to an estimate of original rim diameter and may not correspond to present surface features.
[See more and some images. - LRK -]

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And views from space.
- LRK -

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Asteroid Impact Craters on Earth as Seen From Space

BY BETSY MASON
08.11.09
7:57 PM

impact_aorounga1a

Asteroid impact craters are among the most interesting geological structures on any planet. Many other planets and moons in our solar system, including our own moon, are pock-marked with loads of craters. But because Earth has a protective atmosphere and is geologically active — with plate tectonics and volcanic eruptions, mostly relatively young oceanic crust, and harsh weathering from wind and water — impact structures don’t last long and can be tough to come by.

But on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved. One well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here show some of the biggest, oldest and most interesting impact craters on the planet.
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So we have been impacted before, and probably again. 
Will we be prepared? 
Will it take a government decision? 
Will we (USA) go over the fiscal cliff? --- Sorry, too many questions. :-)
- LRK -

  1. a b "Earth Impact Database"University of New Brunswick. Retrieved 2011-09-18.
  2. ^ Rajmon, D. (March 13–17, 2006). "Suspected Earth Impact Sites"Lunar and Planetary Institute. Retrieved 2008-09-24.
  3. ^ Rajmon, David (2009-07-01). "Impact Database"Impact Field Studies Group (IFSG). Retrieved 2009-08-12.

Thanks for looking with me.
- LRK -
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http://geology.com/meteor-impact-craters.shtml
Meteor Craters - Asteroid Impact Sites - Click an Icon and Zoom In!

Explore fifty of earth's most obvious asteroid impact sites with satellite images and maps. Use the buttons in the upper left to navigate and change your zoom level. To navigate just grab the image and drag it around. Switch between maps and satellite images using the buttons in the upper right. To recenter, double click on the map/image.
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http://www.wired.com/wiredscience/2010/07/google-earth-meteorite/
Researchers poring over Google Earth images have discovered one of Earth’s freshest impact craters — a 45-meter-wide pock in southwestern Egypt that probably was excavated by a fast-moving iron meteorite no more than a few thousand years ago.
Although the crater was first noticed in autumn 2008, researchers have since spotted the blemish on satellite images taken as far back as 1972, says Luigi Folco, a cosmochemist at the University of Siena in Italy. He and his colleagues report their find online July 22 in Science.

The rim of the Egyptian crater stands about 3 meters above the surrounding plain, which is partially covered with distinct swaths of light-colored material blasted from the crater by the impact. These rays, which emanate from the impact site like spokes from the hub of a wheel, are what drew researchers’ attention to the crater, says Folco. While such “rayed craters” are common on the moon and other airless bodies of the solar system, they are exceedingly rare on Earth because erosion and other geological processes quickly erase such evidence.

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WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK -

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