A __________ is the period of revolution of Earth around the Sun relative to the fixed stars

• A. Tropical Year
• B. Anomalistic Year
• C. Sidereal Year
• D. Solar Year

Answer: (C)

When we talk about a year in astronomy, the reference frame matters. The period that marks one full orbit of Earth around the Sun relative to the fixed stars is the sidereal year. It uses distant stars as a stable reference, so it measures the actual orbital period of Earth in space. The tropical year, by contrast, is tied to the cycle of seasons and the vernal equinox, and it runs a little shorter because the equinox point itself shifts slowly due to precession. The anomalistic year is the time between successive perihelion passages, which is another distinct interval. The solar year is often used to refer to a calendar year related to the Sun but not specifically tied to the fixed-star frame.