Your uncle and aunt are astronomers -but not the sort of astronomers who just sit around calculating things. They are much more adventurous than that, and are always travelling to exotic corners of the globe to watch distant nebulae through some of the world's most powerful telescopes. Presently they are staying at the secluded Los Palmos observatory, high up in the mountains. You are lucky enough to be able to visit them there for a week, and you are looking forward to quite an unusual holiday.
    Uncle Jack picks you up at the airport and you begin the long drive up into the mountains. Uncle Jack seems to be absorbed with some problem or other, for he is puffing furiously at his pipe as he often does when he is thinking hard. After a while you stop at a petrol station, and Uncle Jack has just gone inside to pay the attendant when you see a brilliant flare of red light in the sky.

Tell Uncle Jack about the light
Keep quiet about what you saw