Hi Sterling - Oh Joy! - more junk which needs to be watched out for, which NASA will continue to ignore.
While the explosive scaling laws are tough and rough, and I've had a stroke, my best current guess is that cometissimals are around 30 m diameter or so, based on the Rio Curaaca and Rupunini impacts. (Tunguska would be 2 cometissimals accreted.) With age the cometissimals further accrete/condense, depending on the time of their first agregation, which times appear to have a considerable spread. Another fragmentation mechanism besides solar energy may be nearby supernova radiation, which perhaps also provide injection energy. Maybe, appears, possibly, but certainly no one gets any money from NASA to work it out. Would someone fire Weiler now? E.P. Grondine Man and Impact in the Americas --- On Wed, 9/16/09, Sterling K. Webb <sterling_k_w...@sbcglobal.net> wrote: > From: Sterling K. Webb <sterling_k_w...@sbcglobal.net> > Subject: LARGE COMET GIVES BIRTH TO SMALL COMETS > To: "Meteorite List" <meteorite-list@meteoritecentral.com> > Cc: "E.P. Grondine" <epgrond...@yahoo.com> > Date: Wednesday, September 16, 2009, 11:38 PM > I've always assumed > that small comet fragments came from the complete breakup of > the parent comet (didn't you?). But it appears > that comets can produce many, many small comets without > suffering any apparent harm. > Or maybe this is the way comets break up... > slowly? > > Sterling K. Webb > ---------------------------------------------------------------- > http://www.space.com/scienceastronomy/090915-mini-comets.html > > Comet Outburst Spawns Mini-Comets posted: 15 September > 2009 > > A comet recently spewed out a cluster of mini comets in a > huge outburst that was the largest ever witnessed by > astronomers. > > A team of researchers began observing the comet 17P/Holmes > in October 2007, after it was reported that the object, > about 2.2 miles wide (3.6 km wide), had brightened by a > million times in less than a day. > UCLA researcher Rachel Stevenson and colleagues noted > multiple fragments flying rapidly away from the comet's > nucleus. They continued observing for several weeks after > the outburst using the Canada-France-Hawaii Telescope in > Hawaii and watched as the dust cloud ejected by the comet > grew to be larger than the sun. > > The astronomers examined a sequence of images taken over > nine nights using a digital filter that enhances small > features. They found numerous tiny objects that moved away > from the nucleus at speeds of up to 280 mph (125 meters per > second). These objects were too bright to simply be bare > rocks, but instead were more like mini comets, creating > their own dust clouds as ice on their surfaces sublimated > directly to vapor. > > "Initially we thought this comet was unique simply because > of the scale of the outburst," Stevenson said. "But we soon > realized that the aftermath of the outburst showed unusual > features, such as these fast-moving fragments, that have not > been detected around other comets." > > Although the outburst was impressive in the telescope > images, it wasn't visible to the naked eye. > > Scientists aren't sure of the exact cause of the outburst. > Possibly, pressure inside the comet built up as it moved > closer to the sun, until eventually part of the surface > broke away, releasing a huge cloud of dust and gas, as well > as larger fragments. > > Even after ejecting mini comets, the solid nucleus of comet > Holmes survived and continued on its orbit, seemingly > unperturbed. > Holmes takes about 6 years to circle the sun, and travels > between the inner edge of the asteroid belt to beyond > Jupiter. The comet is now moving away from the sun but will > return to its closest approach in 2014, when astronomers > will examine it for signs of further outbursts. > > > ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
