If you want charming (certainly) and informative (largely), I urge you all to visit ‘The Scale of the Universe 2’, which was created by twins Cary and Michael Huang and is headlined as ‘Teenagers create a program that lets viewers compare the sizes of things on earth and in space’. The program – which resides at http://htwins.net/scale2/ – apparently started as a 7th-grade (schoolchildren aged 12–13 years) science project but – like Topsy – just ‘grow’d’ and expanded (!) as Cary collected more information ‘from Wikipedia and astronomy books’ and Michael perfected the programming. The program is interactive and permits scrolling from the smallest ‘thing’ – ‘string’ measured in tiny fractions of a yoctometre (10–35 m) – up to 1027 m, the approximate size of the observable universe. It has plenty of botanical interest too. For example, it not only illustrates but also provides a little explanatory narrative on Rafflesia, chloroplast, mitochondrion (yes, plants have these too – though some 1st year biology undergraduates – 18–19 years old – of my recent acquaintance don’t even know that!), nucleus, coffee bean, duckweed, grain of rice, redwood tree, oak tree and saguaro cactus. It’s not perfect – a legacy of over-reliance on Wikipedia(?) – e.g. it includes sunflower seed (described as 7 mm, but shown converted as 7 × 103 meters [sic – but it’s not the spelling of metre I have the issue with!]) and the sunflower plant, which – correctly – shown at 2.5 × 100 m is actually considerably smaller than the seed it grows from. It also includes the intriguing ‘inch ruler’ (that is actually 30 cm long), and Russell’s teapot, which doesn’t even exist, but if it did, it would be – allegedly – 25 cm long. However, this is a really impressive project and one that’s great fun to explore. So, whether you are in space or on Earth you can now compare the size of things. Well done, twins!