Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: blakestyger on 24/05/2008 11:27:51

Title: Where is the turquoise Sun?
Post by: blakestyger on 24/05/2008 11:27:51

When we see the Sun from Earth it can appear white, yellow or orange depending where it is in the sky and how much air the light has had to pass through to scatter its colours.
As the most intense colours emitted by the Sun are in the blue-green part of the electromagnetic spectrum and these are lost by atmospheric scattering what colour would the Sun appear to be if seen from space? I suggest it should be a sort of turquoise but have never seen an image of it that colour.

Title: Where is the turquoise Sun?
Post by: JP on 24/05/2008 14:34:53

I think it will appear close to white.  The temperature at the surface is ~6000 K, and the blackbody spectrum of something at that temperature can be found here:

http://www.usask.ca/chemistry/courses/243/links/BBR/BBR.html

Title: Where is the turquoise Sun?
Post by: RD on 24/05/2008 14:49:49

Quote from: blakestyger on 24/05/2008 11:27:51

When we see the Sun from Earth it can appear white, yellow or orange depending where it is in the sky and how much air the light has had to pass through to scatter its colours.
As the most intense colours emitted by the Sun are in the blue-green part of the electromagnetic spectrum and these are lost by atmospheric scattering what colour would the Sun appear to be if seen from space? I suggest it should be a sort of turquoise but have never seen an image of it that colour.

On earth the light from the sun can momentarily appear green because of refraction by the atmosphere: "the green flash"...
http://www.icstars.com/Mad/Astro/GreenFlash.html

Our sun is a "yellow-green" star ...
http://apod.nasa.gov/apod/ap000815.html

Title: Where is the turquoise Sun?
Post by: blakestyger on 26/05/2008 10:13:10

Thank you.