Comments on: Questions Show: Orbit of the Planets, Green Stars, and Oort Cloud Contamination http://www.astronomycast.com/listeners/questions-shows/questions-show-orbit-of-the-planets-green-stars-and-oort-cloud-contamination/ Take a weekly facts-based journey through the cosmos with Astronomy Cast. Thu, 11 Mar 2010 05:19:48 +0000 http://wordpress.org/?v=2.9.1 hourly 1 By: craigr http://www.astronomycast.com/listeners/questions-shows/questions-show-orbit-of-the-planets-green-stars-and-oort-cloud-contamination/comment-page-1/#comment-1469 craigr Sun, 11 Jan 2009 15:24:50 +0000 http://www.astronomycast.com/?p=404#comment-1469 I recall that one of the stars in Gemini, Castor I believe, is notably green to the naked eye. I recall that one of the stars in Gemini, Castor I believe, is notably green to the naked eye.

]]> By: Richard Webb http://www.astronomycast.com/listeners/questions-shows/questions-show-orbit-of-the-planets-green-stars-and-oort-cloud-contamination/comment-page-1/#comment-1273 Richard Webb Tue, 11 Nov 2008 01:37:48 +0000 http://www.astronomycast.com/?p=404#comment-1273 As a substance is heated, it emits a blackbody radiation spectra that shifts its peak spectral output from red, to orange, to yello, to green, to blue, and beyond. However, this spectrum is never very narrow, so even when the peak is green, plenty of blue and red are also being emitted. This link shows the colors associated with different temperatures: http://en.wikipedia.org/wiki/Color_temperature Also, this site http://www.techmind.org/colour/coltemp.html has a very nice color ramp image http://www.techmind.org/colour/blackbodyglowinfinity.png Note that 6500 K is what is commonly regarded as a reference white color in the video industry. Colors hotter than this appear bluer, but never greener. Colors cooler that 6500K appear redder. The greenest color you can get from this is white, but you cannot get any greener than that. As a substance is heated, it emits a blackbody radiation spectra that shifts its peak spectral output from red, to orange, to yello, to green, to blue, and beyond. However, this spectrum is never very narrow, so even when the peak is green, plenty of blue and red are also being emitted. This link shows the colors associated with different temperatures: http://en.wikipedia.org/wiki/Color_temperature Also, this site http://www.techmind.org/colour/coltemp.html has a very nice color ramp image http://www.techmind.org/colour/blackbodyglowinfinity.png Note that 6500 K is what is commonly regarded as a reference white color in the video industry. Colors hotter than this appear bluer, but never greener. Colors cooler that 6500K appear redder.

The greenest color you can get from this is white, but you cannot get any greener than that.

]]> By: david dickinson http://www.astronomycast.com/listeners/questions-shows/questions-show-orbit-of-the-planets-green-stars-and-oort-cloud-contamination/comment-page-1/#comment-1258 david dickinson Fri, 07 Nov 2008 12:50:37 +0000 http://www.astronomycast.com/?p=404#comment-1258 During the Winter Solstice in the northern hemisphere, the full Moon is also above the horizon as seen from far northern latitudes for over a week at a time... this is because the full Moon occupies the same region of the ecliptic that the Sun does in the summer. I've set up a simulation of this phenomena on our site, www.astroguyz.com, to illustrate this bizzare motion; the time lapse is set for Alert, Canada, during next month's full Moon. During the Winter Solstice in the northern hemisphere, the full Moon is also above the horizon as seen from far northern latitudes for over a week at a time… this is because the full Moon occupies the same region of the ecliptic that the Sun does in the summer. I've set up a simulation of this phenomena on our site, http://www.astroguyz.com, to illustrate this bizzare motion; the time lapse is set for Alert, Canada, during next month's full Moon.

]]> By: William http://www.astronomycast.com/listeners/questions-shows/questions-show-orbit-of-the-planets-green-stars-and-oort-cloud-contamination/comment-page-1/#comment-1218 William Fri, 31 Oct 2008 20:07:57 +0000 http://www.astronomycast.com/?p=404#comment-1218 Contrary to the answer given in the this podcast, there are places on the earth where the moon is above for more than 24 hours at a time. Inside the Artic Circle during the Northern Summer Solstice, the Sun does not set below the horizon. If you consider the days around New Moon, the moon will be relatively close to the Sun. Being in close proximity to the Sun, the Moon itself therefore does not set below the horizon. For those of you with access to planetarium programmes, set your location to the North Pole and the date to the start of June. Then advance the time hour by hour and you'll see the sun circle the horizon with the Moon leading or following it, all the time above the horizon. It doesn't set for well over a week! Contrary to the answer given in the this podcast, there are places on the earth where the moon is above for more than 24 hours at a time.

Inside the Artic Circle during the Northern Summer Solstice, the Sun does not set below the horizon.

If you consider the days around New Moon, the moon will be relatively close to the Sun.

Being in close proximity to the Sun, the Moon itself therefore does not set below the horizon.

For those of you with access to planetarium programmes, set your location to the North Pole and the date to the start of June. Then advance the time hour by hour and you'll see the sun circle the horizon with the Moon leading or following it, all the time above the horizon. It doesn't set for well over a week!

]]> By: Writingindependence http://www.astronomycast.com/listeners/questions-shows/questions-show-orbit-of-the-planets-green-stars-and-oort-cloud-contamination/comment-page-1/#comment-1217 Writingindependence Fri, 31 Oct 2008 15:10:57 +0000 http://www.astronomycast.com/?p=404#comment-1217 Uranus has the weird rotational axis going sideways too. What's going on with our proto solar nebula hypothesis? Maybe that model needs to be junked, seems we picked up a hitchhiker that coalesced on a different planar orientation than the local norm; or was it far enough out from the sun, slow of period, to simply adopt its own bearings of accretive self organization? Entrainment and the forcing function of the other bodies would seem to govern an extended global attractor basin anisotropy be it ever so weak by the force of gravity over such great distances. Then, given the suspect status of pluto, and Uranus at the edge or limit of planetary attachment, the breakdown of that global basin's influence follows naturally. Neptune is farther out but 2 earth masses heavier than Uranus. I would hazard to guess a far more comprehensive model of p.s.n (proto solar nebulae) would be required in any case to address other issues like abundances, something applying a rescaled model or renormalization of not only separate locales but a representatively entire stellar migratory trajectory's corridor over the span of the entire history of the sun's evolution. We should get out of the isolated bubble model. The biggest gas giants are indeed a fractal scaling down of the solar system with so many moons of their own. Uranus has the weird rotational axis going sideways too. What's going on with our proto solar nebula hypothesis?

Maybe that model needs to be junked, seems we picked up a hitchhiker that coalesced on a different planar orientation than the local norm; or was it far enough out from the sun, slow of period, to simply adopt its own bearings of accretive self organization? Entrainment and the forcing function of the other bodies would seem to govern an extended global attractor basin anisotropy be it ever so weak by the force of gravity over such great distances. Then, given the suspect status of pluto, and Uranus at the edge or limit of planetary attachment, the breakdown of that global basin's influence follows naturally. Neptune is farther out but 2 earth masses heavier than Uranus.

I would hazard to guess a far more comprehensive model of p.s.n (proto solar nebulae) would be required in any case to address other issues like abundances, something applying a rescaled model or renormalization of not only separate locales but a representatively entire stellar migratory trajectory's corridor over the span of the entire history of the sun's evolution.

We should get out of the isolated bubble model. The biggest gas giants are indeed a fractal scaling down of the solar system with so many moons of their own.

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