Water world
There has been an interesting image making its appearance on the web showing what it would look like if you put all the Earth's water into a sphere and placed it on the Earth. The point being made is that it looks quite small so therefore we should be careful with it. I totally agree with taking care of water and all that but was interested in the way the volumes had been compared. I thought I'd compare the water sphere with the moon so made this image. The moon has a diameter about 3,400 km compared to the water which is 1,300 km. Looks like quite a lot of water when viewed like this. Comparing the volume of water with the volume of the Earth is like comparing the volume of paint to the volume of the building it covers. I posted this on facebook too and one of my ex students replied with an interesting question. What radius of solar orbit would the water sphere have for it to remain liquid?