(Posted 10 November 2015) I occasionally get emails (like the one below) about why a star near the horizon is changing colour. Googling the question gets you the answer of atmospheric turbulence (ie wind in the upper atmosphere). Click here for a sample result.
When visiting schools in Canberra with the planetarium I use, I often get the same question. I use the analogy of one of those ‘rainbow crystals’ that children have often seen. Twirling the crystal in sunlight will produce a splash of colours going across the floor. The winds in the atmosphere have a similar effect changing the density of the air and ‘bending’ (refracting) the different colours of the starlight by different amounts. This produces the ‘sparkling star’ effect.
> Hi Paul
>
> I live in XXXXXXX, Brisbane and have been enjoying watching a particular
> star. It is south east of me and at 7.45 pm is just above neighbouring
> tree tops so still fairly low. What makes it special is that it sparkles
> very clearly but with ever changing different colours- reds, yellows, aqua
> blues the whole works. If you know the one I mean, is there a name for
> this star (or is it a “K34x” type name) and can you tell me what makes it
> sparkle so colourfully.
>
> Thanks heaps.
>
> Chris XXXXXX
