iuliu46 |
13.12.2013 17:05:13 |
http://www.scientificamerican.com/ar...hat-we-learned
Ce lectie ne-a invatat cometa ISON ?
"Comet ISON was a rare interloper in the inner solar system from the faraway Oort Cloud, a sphere of comets that surrounds the sun and planets about a light-year away. Its trajectory brought it within just three solar radii of the sun's surface, putting it in a class of brazen comets called "sun grazers." " We've never seen an Oort Cloud [castoff] sun-grazing comet before," Karl Battams of the Naval Research Laboratory in Washington, D.C., said during a postmortem press conference Tuesday at the American Geophysical Union meeting in San Francisco. "It was an unprecedented object." ...
..."One reason Comet ISON was thought to have a chance of survival was because a previous sun-grazing comet called C/2011 W3 (Lovejoy) did withstand an even closer pass by the sun in 2011. By comparing observations of both comets, scientists have theorized about what Lovejoy had that ISON lacked. "Comet Lovejoy was not an Oort Cloud comet," Battams said. "It had been past the sun at least a couple times. It had perhaps built up a thick skin. Maybe that’s a factor." ISON's outer layer was raw and possibly volatile whereas Lovejoy had been burnt by the sun and could have had a hardier crust to withstand the solar heat and pull, scientists said."
Adica oamenii de stiinta au putut pentru prima data sa observe o cometa care vine din faimosul Nor al lui Oort, spre deosebire de alta, din trecut, care nu se stie de unde a venit dar sigur nu a venit din norul respectiv.
Dar stai, Norul lui Oort e doar o ipoteza, el exista doar pentru ca daca universul ar avea miliarde de ani atunci nu ar trebui sa vedem comete, deci hai sa inventam un loc in univers, departe de puterea noastra de observatie, unde se nasc cometele si apoi hai sa aberam despre asta ca sa creada lumea ca stim despre ce vorbim. :)
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