When a train on which I was travelling recently (yes, it was moving, and on time, and I could afford a ticket (that's what's called a miracle!)) entered a tunnel my ears "popped" like they do on aeroplanes. Why does this happen?
I know that there are various "types" of satellite such as geostationary (geosynchronous), spy satellites, communications satellites, weather satellites etc. But how far out in space are they? Are some orbiting closer than others, and do their orbits eventually decay such that they will all fall back to Earth, or will they eventually wander off into space?
What is the temperature inside the average cloud? Are the water droplets that form clouds actually frozen or ice crystals? When it "rains", does the rain start off as snow or hail, and then turn into rain on the way down, if the air temperature is high enough?
I've seen a lot of older people, especially men, with very large ears and noses. It seems unlikely that they were born with such impressive appendages, suggesting that noses and ears continue to grow throughout life.
Is this the case, and given the high prevalence amongst men, is it something to do with testosterone or some other male hormone?
Can someone please tell me about thalidomide. I overheard someone talking about it the other day, and vaguely remember it causing serious problems in the past, but just wondered if anyone could enlighten me please?