In the above video, Mike Merrifield of the University of Nottingham talks about rainbow arcs and other phenomena that occur as a result of light passing through ice crystals in the atmosphere. Watch the video and find out what you can learn about the structure and behaviour of atmospheric ice from the patterns that can sometimes be seen in the sky.

What are the technological marvels of the 21st century so far? The Royal Academy of Engineering has come up with seven as part of its “This is Engineering campaign”. Their “Seven technological wonders of the 21st century” include Hawk-Eye, which allows fans and referees to track the motion of balls in a range of sporting competitions. Another wonder on the list is 3D printed bone implants, which have the potential to improve the lives of people worldwide. However, it was the inclusion of Gore-Tex that made me scratch my head. According to Wikipedia, the breathable waterproof fabric was invented in 1969 and I can distinctly remember people wearing Gore-Tex jackets in the 1980s.