Imagine some alien race is observing the Sun and with their telescope and detector system determine it has a flux of 8.559 x 10^-10. How far away from the Sun are the aliens in lightyears? Take the Sun's luminosity to be 3.85 x 10^26 and note that 1 lightyear = 9.46 x 10^15 meters.
Imagine some alien race is observing the Sun and with their telescope and detector system determine...