On Friday an atmospheric scientist I know from the University of Leeds, Ben Murray, gave a talk on his research. His research is on how ice forms in the atmosphere. It was very interesting, and one of the things I learnt is how big the atmosphere is, and how high up some clouds are. The image above is taken from the International Space Station and at the top of the image are what are called noctilucent clouds.

They can also be seen from the ground, but only at twilight. These clouds can be up to around 85 km up. Which I guess is why there is such a wide gap between the Earth’s surface and the clouds in the image above.

To give you an idea of how high up this is, the summit of Mount Everest is 8.8 km up, so these clouds are ten times higher. Felix Baumgartner’s recent record breaking jump was from around 39 km, pretty high, but less than half as high as these clouds. The International Space Station, which of course is in orbit, is only 370 km up, so these clouds are almost a quarter of the way up into the space station’s orbit. I think that’s pretty amazing.