Question

Parallax angles _______ $0.01/arcsec$ are very difficult to measure from Earth.

• A. more than
• B. less than
• C. equal to
• D. greater than or equal to

Answer 1

The correct option is B less than

Parallax effect depends upon the path of light that travels from object to the observer. For distant objects observed from Earth, the light that reaches Earth has to go through a number of layers in Earth's atmosphere, during which it refracts and disperses and hence decreases the accuracy of the method. Resultantly parallax angles less than $0.01/arcsec$ are very difficult to measure from Earth.