The erroneous theory of Galileo was that tides were a result of the earth's what he called the inconsistent revolution around the sun. He was right about the most important thing of the earth revolving around the sun but didn't realize that the moon (and sun) exert a gravitational pull on the earth's oceans and cause the diurnal tides to occur.
The half-life equation 
in which <em>n </em>is equal to the number of half-lives that have passed can be altered to solve for <em>n.</em>
<em>
</em>
<em>
</em>
Then, the number of half-lives that passed can be multiplied by the length of a half-life to find the total time.
<em>2 * 5700 = </em>11400 yr
