What does rain look like on other planets?

Julia Ravey asked exoplanet researcher and author Hannah Wakeford about the bizarre weather on different planets…

Hannah - We have been trying to look for weather on other planets, we found a number of different things, but I'm going to take us back to your set up there, because what you're talking about is something happening on a very particular scale. On a, "I am a human standing in my less than one meter squared and this thing hasn't happened in that tiny little area I occupy on an entire planet." The scales of weather can be very different and result in different predictions. At some point in the UK, we can say 'it's going to snow on this day' and it probably does somewhere. It's all about scales when you talk about weather. Weather and climate is a chaotic system, small changes make big differences to it. When we're talking about looking at alien worlds, other planets, we're talking about the big scale things. We're talking about the general circulation of the atmosphere, saying that predominantly it's cloudy in the UK, that's a large area of our planet, it's normally pretty cloudy there. The prediction of that is much easier to do than the prediction of something that's happening on a small scale. We're looking over an entire planet when we're looking at these alien worlds and we're saying, "we think we understand what is going on across an entire planet." So it's a little bit more predictable in that sense.

Julia - And does rain fall on other planets?

Hannah - Rain like we have here on the earth made of nice water droplets or ice crystals in our snow, or even in our hail, we don't have that on the planets that we've studied so far because our planets are so much hotter. The rain and snow on other planets is actually made of things that we stand on; rocks, liquid glass, molten iron. The rain in some of these planets will be made out of something called corundum, which is the basis of rubies and sapphires. So on another planet, instead of clouds made of water and rain of water coming down, you have clouds made of rubies and sapphires and rain and snow of rubies and sapphires.

Julia - Shower, me and diamonds, like literally.

Hannah - Diamonds are a little bit tricky. Diamonds require way too much pressure and forming clouds of them is very hard, but we can get you some rubies and sapphires.

Julia - I'll take rubies and sapphires any day of the week.