Posted on 04/02/2006 2:13:59 PM PDT by SunkenCiv
Did a planetary wobble kill the dinosaurs?Bruce Runnegar from the University of California at Los Angeles' Center for Astrobiology... and his colleagues used computer models to map out the Solar System for the past 250 million years. In particular, they looked at the perihelion of each planet - the point in its orbit where it is closest to the Sun. The perihelion of Earth rotates around the Sun with a period of hundreds of thousands of years. Because of subtle tugs and pulls between the planets, this period changes slightly with time... Their model suggests one of these blips significantly changed Mercury's orbit 65 million years ago. This wobble would have pulled at the asteroid belt, increasing the chances that asteroids in the Hungarias region would be knocked out of place. Now the researchers are running a fresh set of models to see how much the orbits of these asteroids changed. It wouldn't have been enough to send a shower of asteroids into the Earth, but Runnegar says the wobble could have sent a single asteroid onto collision course with our planet... Now he is planning to run his models forward in time, to see when the next potentially catastrophic planetary wobble will be.
by Nicola Jones
New Scientist
June 27 2001
Norway Impact Gentler Than Atomic Bomb
By Selby Cull
Sky and Telescope
http://skyandtelescope.com/news/article_1742_1.asp
http://skyandtelescope.com/printable/news/article_1745.asp
http://skyandtelescope.com/mm_images/4950.jpg
"The meteorite that struck northern Norway on June 7th was probably about as energetic as the 2003 Park Forest meteorite. The Park Forest event scattered hundreds of small pieces over the suburbs of Chicago, like the one shown here, which grazed a fire hydrant as it hit. No material from the Norway meteorite has yet been reported. Courtesy Matt Morgan / Mile High Meteorites."
Asteroid Impact Could Have Triggered India-Pakistan Nuclear War, General Says
Space Daily | September 17, 2002 | Staff Sgt. A.J. Bosker, Air Force Print News
Posted on 09/18/2002 10:40:56 AM EDT by cogitator
http://www.freerepublic.com/focus/news/752890/posts
Heavenly Bodies Stir Up Routine Catastrophes
IOL | 3-18-2003 | Graeme Addison
Posted on 03/18/2003 12:33:33 PM EST by blam
http://www.freerepublic.com/focus/f-news/867877/posts
Study Finds Signs of Life in Ancient Lava
Science - Reuters | 2004-04-23
Posted on 04/26/2004 1:14:40 PM EDT by Junior
http://www.freerepublic.com/focus/f-news/1124648/posts
[an omnibus of links to FR topics on Enceladus; omitted some of the Astronomy Picture of the Day because they weren't too informative, and often had nothing but a pinpoint of light to show Enceladus]
http://www.freerepublic.com/focus/keyword?k=saturn
http://www.freerepublic.com/focus/keyword?k=enceladus
What Is Melting the Ice on Enceladus?
CreationSafari.com | 03/04/05 | Creation Evolution Headlines
Posted on 03/07/2005 10:21:10 PM EST by DannyTN
http://www.freerepublic.com/focus/f-bloggers/1358158/posts
On Saturn, a Spacecraft Is Finding New Worlds
NY Times | July 5, 2005 | JOHN NOBLE WILFORD
Posted on 07/05/2005 12:44:14 AM EDT by neverdem
http://www.freerepublic.com/focus/f-news/1436643/posts
Bizarre boulders litter Saturn moon's icy surface (Enceladus)
New Scientist | 7/19/05 | Stuart Clark
Posted on 07/19/2005 2:15:30 PM EDT by LibWhacker
http://www.freerepublic.com/focus/f-news/1446126/posts
Cassini Finds an Active, Watery World at Saturn's Moon Enceladus
JPL web site | 29 July 2005 | JPL
Posted on 07/29/2005 5:24:17 PM EDT by Fitzcarraldo
http://www.freerepublic.com/focus/f-news/1453420/posts
"Hot spot" found on one of Saturn's moons
Reuters - Science | 2005-08-30 | Gideon Long
Posted on 08/30/2005 12:30:12 PM EDT by Junior
http://www.freerepublic.com/focus/f-news/1473481/posts
Tiny Enceladus [a moon of Saturn] May Hold Ingredients of Life
UANews.org (University of Arizona ) | 05 September 2005 | Lori Stiles
Posted on 09/08/2005 7:46:27 AM EDT by PatrickHenry
http://www.freerepublic.com/focus/f-news/1480014/posts
Cassini Images Reveal Spectacular Evidence Of An Active Moon
Space Daily.com | Dec 07, 2005 | JPL, NASA
Posted on 12/07/2005 4:03:39 PM EST by tricky_k_1972
http://www.freerepublic.com/focus/f-news/1535908/posts
Images suggest Saturn moon geologically active
AP Via CNN.com | 12/8/2005 | Staff
Posted on 12/09/2005 4:01:42 PM EST by Red Badger
http://www.freerepublic.com/focus/f-news/1537353/posts
DRUDGE - Big NASA Announcement Set For Today...
Posted on 03/09/2006 10:58:40 AM EST by Vintage1
http://www.freerepublic.com/focus/f-news/1593131/posts
112 posted on 03/09/2006 11:28:09 AM EST by neutrality
http://www.freerepublic.com/focus/f-news/1593131/posts?page=112#112
NASA'S CASSINI DISCOVERS POTENTIAL LIQUID WATER ON ENCELADUS
Drudge Report | Thu Mar 09 2006 11:21:33 ET | Drudge Report
Posted on 03/09/2006 12:00:42 PM EST by phantomworker
http://www.freerepublic.com/focus/f-news/1593182/posts
Coolest Photo You Will Ever SEE! (moon Enceladus)
Posted on 03/09/2006 5:26:03 PM EST by AZRepublican
http://www.freerepublic.com/focus/f-news/1593410/posts
Encore For Enceladus! Saturn Moon Ripe For Astrobiology Exploration
space.com | 04/03/06 | Leonard David
Posted on 04/03/2006 8:15:06 PM EDT by KevinDavis
http://www.freerepublic.com/focus/f-news/1608598/posts
The Whole Enceladus
Science News Online | 05/06/06 | Ron Cowen
Posted on 05/07/2006 2:17:31 PM EDT by KevinDavis
http://www.freerepublic.com/focus/f-chat/1628242/posts
Catastrophes, Chaos & Convolutions
by James P. Hogan
a few more:
Cassini Finds an Atmosphere on Saturn's Moon Enceladus
JPL/NASA/ESA | 3/16/2005 | n/a
Posted on 03/18/2005 1:46:37 PM EST by Pyro7480
http://www.freerepublic.com/focus/f-news/1365632/posts
Scientists Find Water on Saturn Moon
AP via Yahoo News | Mar 9 2006 | Alicia Chang
Posted on 03/09/2006 3:49:41 PM EST by Kjobs
http://www.freerepublic.com/focus/f-news/1593344/posts
Water signs on Saturn moon raises possibility of extra-terrestrial life
AFP | March 10, 2006
Posted on 03/10/2006 11:17:30 AM EST by West Coast Conservative
http://www.freerepublic.com/focus/f-news/1593886/posts
Asteroid Belt Like Ours Spotted Around Another StarThe scientists have not actually seen any asteroids around Zeta Leporis, a young star twice as massive as the Sun and 60 to 70 light-years away. Instead they have studied the temperature and position of the star's swirling mass of debris, which they say shows evidence of chaotic collisions among rocks that creates the dust needed to sustain such a disk... Zeta Leporis, also called HR 1998, is between 50 million and 400 million years old, compared to our middle-aged Sun, which is about 4.5 billion years old. Along with some other young stars, it was found in the 1980s to have a ring of dusty debris. And in 1991 astronomers learned that this debris ring was unusually warm and close to its parent star, unlike other disks that are farther out, and hence colder. This dust, given its known properties, should spiral into a star within 20,000 years, according to current theories of physics and star formation, scientists say. But this star is much older.
by Robert Roy Britt
4 June 2001
Huge Asteroid to Fly Past Earth July 3
Space.com | June 26, 2006 | Joe Rao
Posted on 06/27/2006 10:33:56 AM EDT by DaveLoneRanger
http://www.freerepublic.com/focus/f-news/1656398/posts
Deep ImpactA recent study portrays the paths of asteroids in the inner solar system as a vast Los Angeles-style traffic system crisscrossed with superhighways along which are hurtling huge, rocky projectiles. The study estimates that an armada of asteroids, 900 strong, all a kilometer in diameter or larger, present a potential hazard to life on Earth. Some pass within a few moon distances of Earth every year. William Bottke at Cornell University is lead researcher on a U.S.-French team that has discovered the spatial and size distribution of a large group of asteroids called NEAs (for near-Earth asteroids), a vast system of orbiting rocks in inner space, ranging in size from mere specks to more than 64 kilometers (40 miles) in diameter. Most of the asteroids in the solar system revolve around the sun on independent orbits, corralled between Mars and Jupiter in a formation known as the main belt.
July 23, 2001
Asteroid-impact Study Finds Effects Of Collisions Or Explosions On Small Asteroids May Be Hard To PredictAstronomer Erik Asphaug, a UCSC research associate, used computer simulations to study the effects of powerful impacts on asteroids with different internal structures. He and his colleagues found that the outcome of such impacts depends on the degree to which the asteroid has been fractured and made porous by earlier collisions. "It's a lot more difficult to nudge these asteroids around than we had thought."
by Tim Stephens
June 8, 1998Deflecting Asteroids Harder Than Once ThoughtThe fractured, porous nature of many asteroids may make it difficult to use nuclear weapons or other explosions to nudge them off collision courses with the Earth. The effects of a collision or explosion on an asteroid depend strongly on the interior structure of the asteroid. A solid asteroid, they found, might easily shatter when hit by another asteroid. However, a more porous asteroid, one fractured by previous collisions, would tend to damp out the effects of the collision.
June 4, 1998
Bill Bottke's Asteroid Research Home Page
Department of Space Studies
Southwest Research Institute
http://www.boulder.swri.edu/~bottke/index.html
Wanted: small asteroid for use as slingshot to slay a GoliathScientists at the French space agency, CNES, have calculated how to capture an asteroid and manoeuvre it into a near-Earth orbit, from where it can be flung into the path of a larger asteroid that threatens to collide with Earth... Writing in the journal Acta Astronautica, the scientists show how the asteroid... could be kept in a holding position until it needed to be redirected to intercept a much larger "Goliath". Even if the incoming asteroid was 1,000 times heavier than the orbiting asteroid, the two would still collide at a speed of 23km a second, generating 4 million billion Joules of energy, the equivalent of 40 Hiroshima bombs.
by Ian Sample
The Guardian
Saturday July 15, 2006
Greg Martin space art:
http://www.space.com/php/multimedia/downloads/wallpapers/collection.php?collection=gregmartin
one of my faves, "Cataclysm":
http://a52.g.akamaitech.net/f/52/827/1d/www.space.com/entertainment/downloads/spaceart/images/cataclysm_1024.jpg
The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine in
the History of Civilization
by Richard Firestone,
Allen West,
Simon Warwick-Smith
~bumping~ a valuable resource thread.
Ice sheets drive atmospheric carbon dioxide levels, inverting previous ice-age theory
EurekAlert! News | July 24, 2006 | Staff
Posted on 07/26/2006 3:10:49 PM EDT by DaveLoneRanger
http://www.freerepublic.com/focus/f-chat/1672716/posts
Satellites in prograde motion receive a momentum transfer from the rotating parent body, gradually rising in altitude.N2K Information For Star HD149026The orbital period of HD149026b is remarkably short, 2.88 days. In fact, for this "Hot Saturn", an entire "year" takes place over a single weekend! Orbiting at a distance of just 0.042 AU, the planet's would have a scorching temperature of 1,500 K... HD149026 is in the constellation Hercules in this part of the sky... Radial Velocities of the star HD149026 not only reveal the wobble due to the planet, but also deviate from a perfect sine wave when the planet passes in front of the rotating star. This is called the Rossiter-McLaughlin effect and has been observed for other transiting planets.
San Francisco State University
Object Survives Being Swallowed by a Star
Space.com on Yahoo | 8/3/06 | Ker Than
Posted on 08/03/2006 1:40:47 PM EDT by NormsRevenge
http://www.freerepublic.com/focus/f-chat/1677175/posts
Mass limit on Nemesis
Bull. Astr. Soc. India | after 10 February 2005 | Varun Bhalerao and M.N. Vahia
Posted on 08/04/2006 12:24:16 AM EDT by SunkenCiv
http://www.freerepublic.com/focus/chat/1677507/posts
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