Sun and stars

The lunchtime astronomy lectures at the Museum of London fill the room; people arrive early to get a seat, me among them. The lectures are fascinating ... astronomy is a bit mind-boggling, all those big numbers!

The lectures are on video, at gresham.ac.uk/astronomy-lectures-by-carolin-crawford. The latest in the series started by comparing the size of the Sun and Earth - you need well over a million Earths to fit inside the sun -

watch the whole thing here. It has a good explanation of electromagnetic fields, and of the formation of helium from hydrogen. And lots of big numbers.