Space
Is there a planet where it rains glass sideways?
The short answer
Yes. HD 189733b, a gas giant 63 light-years away, is a deep cobalt blue because its clouds are laced with tiny particles of silicate, which is to say glass. The side facing its star is around 1,000 degrees Celsius, and winds of roughly 7,000 kilometres an hour would blow the glass rain sideways.
In 2013 the Hubble Space Telescope measured the colour of a planet outside our solar system for the first time. The method was elegant: watch the planet pass behind its star, and see which colour of light disappears when it does. The missing light was blue.
The planet is not blue for the reason Earth is. There is no ocean. It orbits so close to its star that a year lasts two days and the daytime side bakes at about 1,000 degrees Celsius. In that heat, silicate condenses into high clouds of tiny glass-like grains, and those grains scatter blue light more than red, the same trick that makes our sky blue.
Add the winds. Measurements suggest gusts of up to 7,000 kilometres an hour, several times the speed of sound, which would drive any falling droplets of molten glass sideways rather than down. It is, as NASA's catalogue puts it, deadly weather. From a safe distance it is also one of the prettiest things we have found.
Sources
- NASA Hubble Finds a True Blue PlanetNASA
- HD 189733 bNASA Exoplanet Catalog