Colour of Mars sky?

animaal

In most of the pictures I've seen from the surface of Mars, the sky is red. Sometimes, the same picture can have the sky more red in one publication than in another.

Some time ago I remember reading an article from some guy who believed that the sky on Mars is actually blue, except for when there's significant dust in the air. He believed that because it's hard for cameras to represent true colour, the pictures are often touched up to make them "more realistic". I've read many other similar arguments since, and also a lot of criticisms of this theory.

Now, a picture in today's Indo. It shows a picture of Mount Sharp, and a sky as blue as anything I've seen on earth.

I suppose it's not terribly important, but I'd love to know if the sky on Mars would actually look blue. Or is it just a very minor conspiracy theory?

Maximus Alexander

Apparently it's quite difficult to get true colour images from Mars because the instruments on probes and landers tend to be designed to maximise science value, rather than generate accurate colours for the eye. Most of the pictures we see are filtered before we see them, including the ones where you see a blue sky.

During the day the sky is yellow-brown, at sunrise or sunset it takes on a pink tinge, except around the sun where it has a bluish hue. The sky colour on Mars is driven predominantly by dust particles in the atmosphere, whereas on Earth it is brought about by the scattering of the light by the air.

That picture of Mount Sharp under a pale blue sky was intentionally recoloured to look more Earth-like because geologists are more familiar with that colour spectrum, so it makes it easier to work from their experience on Earth.

dlouth15

I think most of it is down to colour balance adjustments.

If you take a standard image from NASA for example



and do an automatic colour balance adjustment like many digital cameras do you get something like this.

First one looks better