The human eye can detect light by an intensity as low as about10–9 W/m2. A typical large galaxy, such as our own Milky Way, radiates energy at the rate of about 4.*1036 W. What is the maximum distance from earth of a typical galaxy that can be seen with the unaided eye? (There are only three galaxies that are visible without instruments. One of these, the Andromeda galaxy, shown in the figure below, is about2.*106 light-years from earth—where 1light-year, the distance traveled with light in 1 year, is 9.46*1015 m.)