Day Three

In our absence, Mike B did a whole range of really careful experiments dropping balls into sand. It seems a kind of madness to be trying to scale up from ball-bearings in sand to a stonking great meteorite, but what else can we do?

We tried a bullet, which has huge speed but only a small mass, so it didn't help us as much as we hoped. The end of the challenge was the usual fight with daylight fading fast and last-minute traumas. We were so close with our estimate it was unbelievable - sheer fluke really, our errors were simply HUGE.

Jonathan and Ellen's telescope was a magical creation. The moon looked beautiful and its craters unbelievably clear. An amazing way to finish an amazing challenge!