Question

Cosmic or galactic year is :

• A. year in which a comet arrives.
• B. period taken by Earth to revolve around the Sun.
• C. year in which total solar eclipse occurs.
• D. period of Sun's revolution around galactic centre.

Answer 1

The correct option is D period of Sun's revolution around galactic centre.

The galactic year, also known as a cosmic year, is the duration of time required for the solar system to orbit once around the center of the Milky Way galaxy. The length of one orbit range from 225 to 250 million terrestrial years.
The solar system is traveling at an average speed of 828,000 km/h or 514,000 mph within its trajectory around the galactic center, which is about one 1300th of the speed of light speed at which an object could circumnavigate the Earth's equator in 2 minutes and 54 seconds.