I have always thought that our planet has a lot of water (understatement again). With over 70% of the Earth's surface covered with water, in some parts over 10km deep, any educated person would naturally believe that there is more than enough H20 to go around.
If every drop of water in the world (1.4087 billion cubic kilometres of it) including sea water, ice, lakes, rivers, ground water, clouds, etc. was collected in a single sphere, it would be just over 1400 kms across - barely big enough to cover Eastern Europe.
I still find it hard to believe, nevertheless, the math works out. Click here if you are skeptical.
Photo credit: Adam Nieman / Science Photo Library.