Fascinating image, isn't it?
In case you don't understand what logarithmic means, the following is my attempt at trying to explain it.
First understand what an exponent is, raising a number to an exponent means multiplying the same number over and over again. For example, 10^4 would mean 10 is multiplied 4 times with itself (10x10x10x10), which equals 10,000.
Now, suppose you wanted to find out how many times you would have to multiply 10 with itself to get 10,000. You then use logarithms. If you take the logarithm of 10,000 with 10 as the base of the logarithm, you get 4, which implies you have to multiply 10 four times with itself to end up with 10,000.
You can take any base you like, if you take 2 as the base, and calculate the logarithm of 10,000 you will get 13.2877; which implies you have to multiply 2 with itself 13.2877 times to get 10,000, i.e. 2^(13.2877) = 10,000.
Hopefully, this is clear. Feel free to ask any question in the comments if you have any doubts about this, or about the picture.