Martian Sunset (2009 Jan 10)

[orin stepanek]

http://apod.nasa.gov/apod/ap090110.html

A beautiful Picture. Kind of Eerie though that the hill on the left almost looks as though there are trees on it. With a little imagination it almost looks like a house from the one rock formation. The Mars sunset has a starkness that makes it look like a very lonely place. I don't think I would like to be on the first exploration team to live there on a base so far from Earth. Although I would be anxiously await the Information they send back. 8)

Orin

[bobmarvos]

A beautiful image and the size of the sun just emphasizes how much farther the planet is from the sun than us.
I wonder though, has anyone tried to program the camera to view the night sky at night to see how earth and the constellations look from Mars?

[neufer]

A beautiful image and the size of the sun just emphasizes how much farther the planet is from the sun than us.

It sure emphasizes how big Gusev Crater is.
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OK, the Earth's sky is blue because air molecules scatter blue light; and
sunsets are red because all the blue light has been scattered out.

Mars's sky is red because red dust particles scatter red light; and
sunsets are blue because all the red light has been scattered out.

But...air molecules DON'T ABSORB red light;
whereas, red dust particles DO ABSORB blue light.

Shouldn't red dust particles ABSORB blue light
and thereby make Mars's sunsets gray?

[bystander]

OK, the Earth's sky is blue because air molecules scatter blue light; and
sunsets are red because all the blue light has been scattered out.

Mars's sky is red because red dust particles scatter red light; and
sunsets are blue because all the red light has been scattered out.

But...air molecules DON'T ABSORB red light;
whereas, red dust particles DO ABSORB blue light.

Shouldn't red dust particles ABSORB blue light
and thereby make Mars's sunsets gray?

fine martian dust particles suspended in the thin atmosphere lend the sky a reddish color, but the dust also scatters blue light in the forward direction, creating a bluish sky glow near the setting Sun

I take this to mean that the martian dust scatters red light in all directions, like the earth's atmosphere scatters blue light in all directions, but it also scatters blue light away from the light source, the sun. In this picture, the camera is opposite the sun, so the blue light is scattered towards the camera, providing a blue glow around the sun.

[Chris Peterson]

A beautiful image and the size of the sun just emphasizes how much farther the planet is from the sun than us.

I don't really see that. Depending on the focal length of the camera lens, the Sun could look big or small. This image could have been made from any number of locations on the Earth and it would have looked the same (with a slightly different lens). That is, from the image alone, there is no way of judging the distance to the Sun.

I wonder though, has anyone tried to program the camera to view the night sky at night to see how earth and the constellations look from Mars?

Yes, there are some night shots. The camera isn't sensitive enough to show a lot of stars, but some are visible. Meteors have been recorded, and so have the Earth and the Martian moons. The constellations, of course, look just the same from Mars as they do from Earth. The Earth looks like a bright star.

[orin stepanek]

Hi Chris! Wouldn't the sun appear to be a bit more than a bright star from Mars? The explanation says that the sun would appear to be about 2/3 the size as on the Earth; and it still gives Mars pretty good daylight.

Orin

[bystander]

Wouldn't the sun appear to be a bit more than a bright star from Mars?

The Earth looks like a bright star.

[orin stepanek]

Wouldn't the sun appear to be a bit more than a bright star from Mars?

The Earth looks like a bright star.

Thanks bystander! I misread it!

Orin

[kjsaint]

I have been absolutely fascinated by all the pictures of the Martian landscape...just imagine standing there on another planet. The sunset is eerie, I agree but just the fact that it is another world, another planet makes it the most beautiful site I have ever seen.