[meteorite-list] Multiple Impact and 73P(was..More Evidence Chicxulub..)
From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Thu Mar 30 21:43:11 2006 Message-ID: <2a7.eb4dad.315da058_at_aol.com> Sterling W. writes: << Keller-Harting get lots of press, but nobody is convinced by them but them... >> Hola Sterling, That isn't entirely true. Gerta and her many European and Mexican collaborators have done much superb chonostratigraphic detective work and have been quite influential and have at least 15 years of solid science they've built. That the original theorists have every right to defend for their dramatic extinction scenario hypothesis is fine and healthy to a point, but the devil is hiding in the details, and Marcus Harding's work takes this to a new level by attempting a look further at morphology and chemistry like has not been done before. That is a good thing and these are exactly the type of folks needed since the geological record is so...errr...fragmented in the critical scheme of evaluating the hypothesis of the Nobel Prize winning Hollywood Impact Theory. This work is fresh research on a question that is so complicated that other researcher's won't touch since the possibility of successfully nailing it is slim after all of these 65.X million years. The fact the the press and more importantly the scientists themselves seem to be vocally passionate about their hypotheses does not excuse the true inconclusivity of the evidence for the accepted theory which merits keeping the issue on the table for the mainstream. Dr. Keller wisely sticks to her paleontological expertise, but if you have had an opportunity to discuss this with her you will know that her thinking regarding the killer asteroid scenario is quite refreshing and robust. The idea that multiple impacts ocurred doesn't seem to far fetched, and we can basically thank them for introducing it as potentially more viable and consistent based on top-notch fieldwork, not just astronomical mullings. If you want to dream up a nice scenario just look at the two dozen large pieces of Comet Shoemaker-Levy that pummelled Jupiter for over a week. Of course, Jupiter has pretty high-test fishing line compared to Earth and can land these beasts on the first try. So, let's have fun in about a month with some binoculars where you'll see two cometary fragments from Comet 73P Schwassmann-Wachmann 3 on May 12 and 14 even from somewhat light polluted skies at nice, forgiving altitudes for backyard astronomers. Component C, apparently the main mass, passes 0.08 AU from earth first (on a sky trajectory before the 11th of May entering Vulpecula the Fox between the base of the cross of Cygnus the Swan and the second front leg of Pegasus the Flying Horse, and then less than two days later, at only 0.066 AU just about leaving Vulpecula and entering Pegasus another huge mountain of component B will be whizzing by. Some of these chunks are in the 500 meters to 1 kilometer diameter range. There are over a dozen killer chunks detected so far. Some good food for thought while there's still food and thought available:) Too bad NASA lost the CONTOUR spacecraft a month after it was launched in July 2002. If the heliocentric booster maneuver hadn't been a failure, on June 18, Contour (That's COmet TOUR, not COmetS:)) would have made the most dramatic flyby of 73P than anything we have yet witnessed in our fortuitous livespans... There'll be a basically moon out for 73P as it passes Earth most closely so unfortunately the binocular view won't be very astounding and may only catch the largest C fragment. The best time to see the comet if you are serious is on May 7 or 8 at about 3:30 AM local time. During this time the main mass of the comet will be visiting the small, bright parallalelogram in Lyra the Lyre. Just find Vega in Lyra, then the second brightest star in the constellation and follow the side of the parallelogram where the Ring nebula is. The Comet will be brushing by it for some nice opportunities in moderate telescopes to bag the comet and nebula together...(and the nucleus will be visible in your binocular, though the Ring Nebula probably not unless you have some 30X100mm's)... Clear Moonless Skies,. Saludos, Doug Received on Thu 30 Mar 2006 03:58:00 PM PST |
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