Aristarchus's critics argued that parallax was not observed and therefore the Earth could not be in motion. In fact we know now that the stars are very far away and parallax motion is very small. Let's examine this by estimating the change in angular size of the angular separation between two stars 10 light-years away from the Sun. The two stars are 3 light-years apart. Calculate the angular separation of the two stars when the Earth is closest to them in its orbit and when it is farthest away, on the opposite point on its orbit. If human vision (without the aid of a telescope) can at best distinguish a difference of about $0.02^{\circ},$ would the change in angular separation be detectable to the naked eye?