Which of the following methods is used to measure the velocity and direction of motion of gas in the galaxy?

Question

Quizplus · Accepted Answer

The Doppler effect is used to measure the velocity and direction of motion of gas in the galaxy by observing the shift in the wavelength of light emitted by the gas due to its motion towards or away from us. This provides information on the velocity and direction of motion of the gas in the galaxy. Main-sequence fitting on an H-R diagram is used to determine the distance and age of a star, parallax is used to measure the distance to nearby stars, and transit method is used to detect exoplanets.

Which of the Following Methods Is Used to Measure the Velocity