[extropy-chat] Frozen water ice found by ESA Mars Express on Mars.

[Mike Lorrey]

--- Bret Kulakovich <bret at bonfireproductions.com> wrote:

> 
> At the distance of Mars, there is substantially less light, Jupiter  
> and Saturn even less. The images we see are being "pushed" into our  
> range of brightness. 

Mars, at opposition, is only about 40 million miles away, which is
about 40% further from the Sun than Earth (at 93 million miles).
Sunlight at Earths surface is 40% LESS than in Low Earth Orbit because
of the thickness of our atmosphere (orbital solar flux in the visible
range is over 1.4 kw/m^2, sea level solar flux is about 1.0 kw/m^2). As
Mars' atmosphere is quite thin, only about 6 millibars, it does not
attenuate Mars orbit solar flux by a significant percent. Therefore it
follows that the brightness of sunlight on the surface of Mars is
relatively close to that on the surface of Earth.

You are otherwise correct vis a vis Jupiter and Saturn.

Mike Lorrey
Vice-Chair, 2nd District, Libertarian Party of NH
"Necessity is the plea for every infringement of human freedom.
It is the argument of tyrants; it is the creed of slaves."
                                      -William Pitt (1759-1806) 
Blog: http://intlib.blogspot.com

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