I think it is. I asked you, " How old do scientists think the Earth is?" You said, "5.5 billion years." and I'm afraid you were wrong, Phil. It's 4.5 billion years. OK. Let's recap the vocabulary we've learnt, starting with the idiom my jaw dropped, which is used to say someone looks very shocked and surprised. A hypothesis is a suggestion that's proposed to explain something, which can then be..