Astro Physics Question:

The earth and its weight. It is impossible to find out the
weight of the earth by any type of balance. If we express it
in tons, the number of zeros required to do so would occupy
almost more than half of a volume of this book. Therefore,
we will try to express it in a simpler way as follows.

Take an example of hollow ball of the same size as the earth
consisting entirely of water (i.e. a solid ball of water).if
we weigh this ball we find this 5 1/2times lighter than that
of the weight of the earth. This is actually means that the
relative 5 1/2 or 5.5.