What happens with an eclipse with the moon is the Earth passes exactly between sun and the moon, so basically the Earth's shadow is cast on the surface of the moon. Which is why you get that dark colour going across the surface, its sort of a reddish colour basically because you're getting a little bit of light filtering round the edge of the Earth through the atmosphere. The atmosphere lets red light get through better than blue light so you get a reddish tinge to the moon. Other things do get eclipsed, with the sun that's when the moon passes exactly between the Earth and the sun. Actually the day before the lunar eclipse we had an occultation of Saturn, where are moon passed exactly between us and Saturn. So Saturn disappeared out of view, you get the same affect from stars and other planets. They can be really useful things to watch; you can find out about the atmospheres of other planets by watching the stars vanish behind them.

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It's a really good way to detect a planet around another sun. As the planet passes in front of that other star it blocks out a little bit of the light and it goes slightly dimmer for perhaps a few hours and we can actually see that from the Earth sometimes and actually work out that there's another planet orbiting around another star somewhere.

They will carry on using some electricity but it will be significantly less than it would be using whilst you were charging the phone or whatever. They're not made perfectly and if you don't draw any current they still use some just to heat themselves up and you get losses in places, its quite small maybe less than a fifth of a watt.

It would certainly work. Drying things by evacuating them definitely works, its how chemists dry chemicals quite often and its how you freeze-dry things like coffee. To be honest I don't know quite how the thermo-dynamics work or whether you use more energy or less energy than you would by just burning gas and heating it up.

When you actually have a meteor or an asteroid hitting the Earth it doesn't create a nuclear reaction its literally just the energy from the speed that it hits. If you drop a stone off the Empire State building it will probably hit the floor at a few metres per second, when an asteroid comes in and hits the Earth its probably coming in at maybe 20km per second. Incredibly fast – what we call hyper-velocity, and literally that energy from such a massive object, it could be hundreds of metres or even kilometres across, hitting something and basically stopping dead – all that energy from the speed it was going at gets immediately converted into heat or sound waves propagating through the crust of the Earth. It can do immense damage to the Earth and basically blast vast amounts of rock and debris up into the atmosphere which can cause climate change and all sorts of nasty problems.