At lunchtime I attended an event designed to bring the Committee’s Chemistry and Culture Week to an end. For the past three days we have had a scale model of the solar-powered aircraft, Solar Impulse, on display in our entrance hall. The model is huge (the wing span is four metres). The model was loaned by Solvay, which has invested heavily in the Solar Impulse project. Today the project was explained to us by a young scientist, Nicholas Edwards. The aim is to enable a solar-powered aircraft to circumnavigate the world. It won’t be Solar Impulse, which is an experimental craft. In particular, the cockpit for the pilot is far too cramped to sustain lengthy flight and so an even bigger craft is being built. Already, though, Solar Impulse is impressive, with its 64 metre wingspan. The project team like to say that it is the size of an Airbus with the weight of a car but the power of a scooter. The prototype has passed a number of milestones, including flying all night. Edwards explained that this was done by a combination of battery-powered flight (the batteries having been charged during the day) and gradually losing altitude and gliding downwards slowly until sunrise. The next steps are trans-continental and trans-Atlantic flights. These will require a pressurised cockpit and advanced avionics to cope with altitude (the plane will cruise at 12,000 metres) and hence an 80 metre wingspan. Ultimately, a two-seater version is planned to allow for a non-stop flight around the world. Solar Impulse is, literally, a dream coming true.