With the ever increasing shortage of water in reservoirs, why can't we purify seawater to overcome the problem?

How many satellites are currently circling the Earth?

How do 3D glasses work, and if you need these 3D glasses to appreciate the effect at the end, how do they produce them in the beginning?

Which way does the Earth travel around the sun and is the sun spinning and moving too?

What makes the Earth spin and will it ever stop?

We know that meteorites hit the Earth quite well. The sun is hundreds of thousands times bigger than the Earth, and so consequently I would imagine that it would attract many more meteorites. Is this the case?

Whenever you replace tyres on your car, you notice that the tread has worn away. Where does all the rubber go? You don't see it piling up on the sides of roads or creating dust anywhere that I know of.

If you get an ice cube and put it in a glass of water, when it melts it has exactly the same volume. This is the reason that when glaciers melt, there's absolutely no difference in sea level. So the people who say about global warming and sea level rises have got it wrong.

As a radio amateur, I know that trying to get a signal very far away is hard unless the conditions are exactly right. How do NASA manage to get signals all the way into space? Do they have different equipment?

New Horizons is supposed to be the fastest spacecraft yet. I'm wondering when it will surpass the Voyagers as the farthest spacecraft from Earth.

I have question about meteors. If someone was to land on one, would they have to hold on like if they were on the edge of a car moving down the road or would you even notice you were moving like we don't notice on Earth?

If it takes huge dishes to send signals into space, how do things like Venus or Mars rovers send their signals back when they send us their data?