What do the astrometric, doppler, and transit methods share in common? a. what do the astrometric, doppler, and transit methods share in common? b. they all allow us to measure a planet's size (radius). c. they all search for planets by measuring properties of a star rather than of the planets themselves. d. they all require very high-resolution imaging. e. they all require high-resolution spectroscopy. f. all of the above.

Astrometric, Doppler, and transit methods share in common as they all search for planets by measuring properties of a star rather than of the planets themselves.

Option C

Explanation:

Astronomers always try to discover new planets and galaxies. They employ various methods for finding new planets which include astrometric, transit and Doppler method. All these methods have one common aspect in their approach for finding new planets is that they measure the properties of star instead of planets.

Planets are smaller compare to its parent stars. Therefore, it is difficult to detect light from planets as the light of their parent star washes out the light of planet hence making it difficult to detect the planets.

answer; criterion validity