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Posted on 10/27/2004 7:54:44 AM PDT by cogitator
Chance Of A Cometary Impact Re-assessed
The chances of the Earth suffering a collision with a cometary body may be higher than previously thought, according to new research by astronomers Bill Napier and Chandra Wickramasinghe.
If so, international programmes designed to detect a large class of potentially threatening objects, namely near-Earth asteroids, as well as strategies to mitigate the worst effects of collisions, may be in need of urgent review.
This is the disturbing conclusion reached by the astronomers in a paper which is to be published shortly in the Monthly Notices of the Royal Astronomical Society.
Their argument is based on the known rate at which comets enter the inner solar system from the Oort cloud, a nearly spherical swarm of some 100 billion comets that surrounds the solar system out to a distance almost halfway to the Sun's nearest neighbouring star.
With about 1 percent of incoming comets ending up on relatively short-period Earth-crossing orbits, it is expected that several thousand dormant comets could be currently posing a potential threat to our planet.
Recent surveys of the Earth's immediate vicinity should have turned up some 400 such objects, whereas only a handful have so far been found.
The researchers dismiss the current belief that all the "missing" comets have disintegrated into meteor streams. If this had happened, they argue, then we should be seeing a far greater number of meteor showers and a much brighter zodiacal cloud than is observed.
They propose instead that the majority of these comets have become exceedingly black, with such low surface reflectivities that they could not be observed against the blackness of space by optical means.
Surfaces reflecting less than 0.1 percent of the incident sunlight could be formed when a comet made up of a mixture of organic grains and ices approaches the sun and sublimates, leaving an outer layer of loosely connected organic material.
> But at the cost that it would take NASA to do this ...
Who said NASA? I want the Air Force and the US Marines running this show. Soon enough, they'll transform into Fleet and Mobile Infantry....
In order to really protect from EMP, I would GUESS (SWAG) that you would have to be outside the Van Allen Belt at the very least, and preferentially beyond the Earth's magnetosphere.
As for frying all the satelites, sure, I am into planned obsolecense - new satelites in the same slots now occupied by dead satelites means more capability. Only one question: How do you clean up near-Earth space? I mean, the maintenance flights to rendezvous with the hulks, attach deorbitting engines, and sling them back to Earth is huge. Assuming that the satellites are all dead, then perhaps the best thing would be to fill near Earth space with gas (boil a few comets?), which would act to deorbit the dead ones.
Orions are still the best use for obsolete nuke weapons.
> How do you clean up near-Earth space?
The new WPA.
> sling them back to Earth is huge
Bah. Thousands of tons of metal already on orbit would be useful things to have if you plan on having space-based industry or colonization. Don't drop 'em... use 'em.
> Orions are still the best use for obsolete nuke weapons.
Nope. Orion woudl need *all* *new* nukes. Bomb-nukes are wholly inappropriate. Until you get to Really, Really Friggen GIANT Orions, you need bombs with yields of one kiloton or less. Very low yield nukes have been built (the Davy Crockett, frex), but they are incredibly filthy and wasteful, and not that reliable. Orion will need a whoel new bomb development program to produce sub-kiloton, dirt-cheapt, preferable fission-free nukes. They would also be just the thing for *other* applications. Bad guy in a cave? Fine. BOOM.
this topic is from 2004, thanks cogitator.
Comet Holmes is Bigger than the Sun
Universe Today | November 13th, 2007 | Fraser Cain
Posted on 11/14/2007 10:06:58 PM EST by annie laurie
http://www.freerepublic.com/focus/f-chat/1925933/posts
12 posted on 11/15/2007 1:31:47 AM EST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1925933/posts?page=12#12
[warming] Cometary impacts and ice-ages
Source: Astrophysics and Space Science
Published: April 2001 (275: 367-376)
Author: Sir Fred Hoyle and Chandra Wickramasinghe
Posted on 04/07/2001 21:47:15 PDT by Steve Schulin
http://www.freerepublic.com/forum/a3acfed532bff.htm
Evidence Of Tunguska-Type Impacts
Over The Pacific Basin Around The Year 1178 AD
SIS Conference | Emilio Spedicato
Posted on 01/26/2003 12:36:14 PM EST by blam
http://www.freerepublic.com/focus/news/829934/posts
Astronomers unravel a mystery of the Dark Ages
EurekAlert | 3-Feb-2004 | Dr Derek Ward-Thompson
Posted on 02/03/2004 5:54:24 PM EST by ckilmer
http://www.freerepublic.com/focus/f-news/1070892/posts
Comets spread Earth-life around galaxy, say scientists
Cardiff University | 10 February 2004 | Staff
Posted on 02/12/2004 9:30:56 AM EST by PatrickHenry
http://www.freerepublic.com/focus/f-news/1076665/posts
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