Solar HERO: As the sun...

[Basil]

As the sun sinks slowly (http://antwrp.gsfc.nasa.gov/apod/image/0901/PIA07997_spiritmars.jpg)in the west....

on Mars! (http://antwrp.gsfc.nasa.gov/apod/ap090110.html)

Cool, ain't it? ;)
Enjoy the pix. :D

[Jomster]

That's quite impressive! Doesn't look as red from underneath the atmosphere does it?

Would be a nice pic to include as a handout though... at which point you say to the players "No that's right, the sky doesn't look as red from the surface does it? But that's how it really is!" A ripple of applause goes round the table at your most impressive research for the session... Either that or someone says "I bet you got that off one of Basil's Solar Hero posts didn't you?"

Busted! :)

[Cancer]

On Earth, the sky looks red at sunset because Rayleigh scattering removes most of the blue from the direct rays from the Sun, scattering it in all directions, making for the blue sky. On Mars there's far fewer molecules in the atmosphere ... the atmospheric pressure is 0.007 that of Earth, while gravity is 0.38 gees, so the mass of the atmosphere is only about 2% that of Earth (and because that atmosphere is mostly CO2 instead of N2 & O2, that also means there's roughly 1/3 as many molecules per unit mass, and scattering is a per-molecule rather than a per-mass phenomenon) ... so rather less scattering.

During brighter parts of the Martian day the Martian sky looks pink because of the scattering by the reddish dust particles in the atmosphere. The scattering cross-section for the (much larger) dust molecules wins over the Rayleigh scattering cross section of the molecules even though the latter are much more numerous.

[Jomster]

On Earth, the sky looks red at sunset because Rayleigh scattering removes most of the blue from the direct rays from the Sun, scattering it in all directions, making for the blue sky. On Mars there's far fewer molecules in the atmosphere ... the atmospheric pressure is 0.007 that of Earth, while gravity is 0.38 gees, so the mass of the atmosphere is only about 2% that of Earth (and because that atmosphere is mostly CO2 instead of N2 & O2, that also means there's roughly 1/3 as many molecules per unit mass, and scattering is a per-molecule rather than a per-mass phenomenon) ... so rather less scattering.

During brighter parts of the Martian day the Martian sky looks pink because of the scattering by the reddish dust particles in the atmosphere. The scattering cross-section for the (much larger) dust molecules wins over the Rayleigh scattering cross section of the molecules even though the latter are much more numerous.

That's a quote to steal for the team's science officer right there! Thanks! :)

[Nolgroth]

Kinda answers the "Daddy, why is the sky blue?" question at the same time too. ;)

[ghost-angel]

Kinda answers the "Daddy, why is the sky blue?" question at the same time too. ;)

A kid asked me that once.

I told him I ordered Green but someone screwed up and we got this blue instead. And I'm still waiting on the refund.