• Question: Are stars really white?

    Asked by iamginger to Arttu, Ceri, James_M, Monica, Philip on 23 Jun 2011.
    • Photo: Arttu Rajantie

      Arttu Rajantie answered on 18 Jun 2011:

      Actually stars have different colours depending on their temperature: hotter stars are blue and colder stars are red. They all look white because we only see a point of bright light, and our eyes cannot tell which colour it is, but if you look at them with a telescope you can see the colours.

    • Photo: Ceri Brenner

      Ceri Brenner answered on 23 Jun 2011:

      arttu’s got it spot on here. Stars give off radiation in the form of electromagnetic waves, from ultraviolet all the way up to infra red. We can only detect the visible bit of the spectrum using our eyes alone and furtherstill, we cannot distinguish between the different colours when the light is so far away

Comments

  • Photo: iamginger

    iamginger commented on :

    But why are colder stars red, I know why hot stars are blue?

    • Photo: iamginger

      iamginger commented on :

      I only know this because my smart friend told me so… who is coincidently sitting next to me <-

    • Photo: strangeness

      strangeness commented on :

      The energy of red light is lower than the energy of blue light, because red light has a lower frequency than blue light. So a hotter star, with a higher energy, will be bluer whereas a cooler star, with a lower energy, will be redder. Actually some stars do look slightly redder or bluer than others even without a telescope – for instance Betelgeuse looks red but Rigel looks blue (they’re both stars in the constellation of Orion). You do have to have been in the dark for a little while before you can see this though, as your eyes need to be dark-adjusted to appreciate the difference in the colours from these dim-appearing stars. Hope that helped! 😀