• Question: why are planets different colours

    Asked by beaver1997 to timcraggs, Jo on 24 Jun 2010 in Categories: .
    • Photo: Joanna Buckley

      Joanna Buckley answered on 23 Jun 2010:

      Hiya beaver1997 🙂

      Light from the sun bounces off things around us. Light is made of little bits called photons and the sun shines photons of all wavelengths onto earth and when they bounce off stuff, they enter our eyes.

      When they do, special cells called photoreceptors tell our brains about the light. It depends what wavelength of light you’re looking at. When light enters your eye and strikes the retina, colour-sensitive cones are excited and they interpret the light’s wavelength into a nervous impulse that is sent directly to your brain. There the impulse is processed we see certain colours.

      So basically, plants of different colours emit different wavelengths of light from the sun which via our eyes and brains, we see as colours. Hope that helps 🙂

      Are you colourblind, beaver1997? You can try this simple test to find out if you are here…

      http://askabiologist.asu.edu/are-you-color-blind

    • Photo: Tim Craggs

      Tim Craggs answered on 24 Jun 2010:

      Hi Beaver,

      Good question. I think that it is because they are made up of different materials. I found this article in the web which explains it quite well:

      Planets have the colors that they have because of what they are made of and how their surfaces or atmospheres reflect and absorb sunlight.

      Mercury has a dark gray, rocky surface which is covered with a thick layer of dust. The surface is thought to be made up of igneous silicate rocks and dust.

      Venus is entirely covered with a thick carbon dioxide atmosphere and sulphuric acid clouds which give it a light yellowish appearance.

      Earth shows its blue oceans and white clouds as well as its green and brownish land.

      Mars is covered with a fine dust which contains iron oxide (rust). This gives Mars its orange color.

      Jupiter is a giant gas planet with an outer atmosphere that is mostly hydrogen and helium with small amounts of water droplets, ice crystals, ammonia crystals, and other elements. Clouds of these elements create shades of white, orange, brown and red.

      Saturn is also a giant gas planet with an outer atmosphere that is mostly hydrogen and helium. Its atmosphere has traces of ammonia, phosphine, water vapor, and hydrocarbons giving it a yellowish-brown color.

      Uranus is a gas planet which has a lot of methane gas mixed in with its mainly hydrogen and helium atmosphere. This methane gas gives Uranus a greenish blue color

      Neptune also has some methane gas in its mainly hydrogen and helium atmosphere, giving it a bluish color.

      Pluto (now classified as a dwarf planet) – there are no pictures of Pluto which give us a good view of its surface yet, because it is too far away. Pluto may be covered in ice.

      http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/planets_colors.shtml

Comments