CBSE Class 11-science Answered
Gross errors are undetected mistakes that cause a measurement to be very much farther from the mean measurement than other measurements.
The indirect methods of distance measurement.
Spectroscopic method: By measuring the Doppler shift in the spectrum of light received from a distant star, we can infer the distance of the star and it's recessional velocity from earth.
Kepler's Method: By using the Kepler's third law, we can measure the distance of a planet. We have to record it's time period to use this method, against a known time period and distance data for a planet.