What is the double value returned by the NOW suppose to represent?

It looks as though the .00001 place is seconds. Is this true?

Example Output:
Object 1: 36804.4683217593
Object 2: 36804.4683333333
Object 3: 36804.4683449074
Object 4: 36804.4683564815
Object 5: 36804.4683680556

My end result is trying to find out how many seconds it takes to go from one object to the next with some acuracy.

Thanks