It really depends upon what you read and who you believe. Personally, I do not want to pass through one at close range.
A comet has two or more tails, a dust tail and ion tails. The ion tail is gas and ionized or charged particles. As a result of outgassing, comets leave a trail of solid debris. If the comet's path crosses Earth's path, then at that point there are likely to be meteor showers <http://en.wikipedia.org/wiki/Meteor_shower> as Earth passes through the trail of debris. The Perseid meteor shower<http://en.wikipedia.org/wiki/Perseids>, for example, occurs every year between August 9 and August 13, when Earth passes through the orbit of Comet Swift–Tuttle<http://en.wikipedia.org/wiki/Comet_Swift%E2%80%93Tuttle> .[36] <http://en.wikipedia.org/wiki/Comet#cite_note-showers-36> Halley's comet <http://en.wikipedia.org/wiki/Halley%27s_comet> is the source of the Orionid shower <http://en.wikipedia.org/wiki/Orionids> in October.[36]<http://en.wikipedia.org/wiki/Comet#cite_note-showers-36> We do not even come very close to Swift-Tutle and it triggers meteor showers. Comets were found to emit X-rays <http://en.wikipedia.org/wiki/X-rays> in 1996.[14] <http://en.wikipedia.org/wiki/Comet_tail#cite_note-14> This surprised researchers, because X-ray emission is usually associated with very high-temperature bodies<http://en.wikipedia.org/wiki/Black_body_radiation>. The X-rays are thought to be generated by the interaction between comets and the solar wind: when highly charged ions<http://en.wikipedia.org/wiki/Ions> fly through a cometary atmosphere, they collide with cometary atoms and molecules, "ripping of" one or more electrons from the comet. This ripping off leads to the emission of X-rays and far ultraviolet<http://en.wikipedia.org/wiki/Far_ultraviolet> photons <http://en.wikipedia.org/wiki/Photon>.[15]<http://en.wikipedia.org/wiki/Comet_tail#cite_note-15> I think you are right about the vacuum, vacuum energy that is, from comet nuclei. Stewart On Wed, Feb 27, 2013 at 4:42 PM, Jed Rothwell <[email protected]> wrote: > ChemE Stewart <[email protected]> wrote: > > Just getting whacked by the either the ion tail or the dust/debris tail >> could be a terrible event. >> > > I do not think so. I have heard that the tail of a comet is practically a > vacuum. The whole volume of earth has only grams of mass. > > So, a miss is just a miss. The fundamental things apply. (Newtonian > physics). > > > >> One of the twenty or so Shoemaker-Levy 9 nuclei left a dark spot on >> Jupiter the size of the Pacific Ocean. >> > > The nucleus has all the mass. > > The UniverseToday article confirms that the energy release is estimated at > 2*10E10 MT. (20 billion MT). > > - Jed > >
