| Ultimi commenti - Asteroids and Comets |
Comets-Comet_Siding_Spring-PIA12836.jpgComet Siding Spring64 visiteCaption NASA:"Is it a bird, or a plane? It's comet Siding Spring streaking across the sky, as seen by NASA's Wide-field Infrared Survey Explorer, or WISE.
The comet, also known as C/2007 Q3, was discovered in 2007 by observers in Australia. The snowball-like mass of ice and dust spent billions of years orbiting in the deep freeze of the Oort Cloud, a spherical cloud of comets surrounding our Solar System. At some point, it got knocked out of this orbit and onto a course that brings it closer to the Sun. Sunlight has warmed the Comet, causing it to shed ices and dust in a long tail that trails behind it.
On October 7, 2009, comet Siding Spring passed as close as 1,2 Astronomical Units from Earth and 2,25 Astronomical Units from the Sun (an Astronomical Unit - AU - is the distance between the Sun and Earth). Now, the comet is leaving the warmer, more hospitable neighborhood of the Solar System and heading back out to chillier parts. In this view, longer wavelengths of InfraRed Light are red and shorter wavelengths are blue.
The comet appears red because it is more than ten times colder than the surrounding stars. Colder objects give off more of their light at longer wavelengths.
An ice cube, for example, pours out a larger fraction of its light at longer InfraRed wavelengths than a cup of hot tea emits".MareKromium04/15/10 at 14:04walthari: MareK, per mandarti la mia ultima fatica, un elabo...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/15/09 at 00:18MareKromium: Pi? informazioni = pi? confusione (se poi, accanto...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/13/09 at 18:12cicas65: Grazie per aver risposto alla mia domanda. A dire ...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/13/09 at 09:37george_p: Meglio cosė allora. Giorgio
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/13/09 at 07:14Gianluigi: Comunque leggendo le news non dai quotidiani ma da...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/12/09 at 22:15george_p: Dopo quello scritto dal Doc in persona aggiungerei...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/12/09 at 22:00MareKromium: Mi permetto di rispondere all'Amico CICAS65. T...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/12/09 at 21:56george_p: Ciao, per ci? che mi riguarda non credo quasi a ni...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/12/09 at 21:53titanio44: oh cos?.....st? solo aspettando che qualcuno comin...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/12/09 at 21:39cicas65: PER QUALE MOTIVO NON CREDETE ALLA NOTIZIA RIGUARDA...
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/12/09 at 21:24george_p: Caro Marco ti Quoto a ruota! Giorgio
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Asteroid_DD-45-d.gifAsteroid 2009 DD-45 (GIF-Movie)151 visitenessun commentoMareKromium03/12/09 at 20:57titanio44: questa sera 12 3 09 hanno trasmesso sul tg una not...
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