Question

How will you ‘weigh the sun’, that is estimate its mass? The mean orbital radius of the earth around the sun is 1.5 × 10⁸ km.

Answer 1

Orbital radius of the Earth around the Sun, r = 1.5 × 10¹¹ m

Time taken by the Earth to complete one revolution around the Sun,

T = 1 year = 365.25 days

= 365.25 × 24 × 60 × 60 s

Universal gravitational constant, G = 6.67 × 10^–11 Nm² kg^–2

Thus, mass of the Sun can be calculated using the relation,

Hence, the mass of the Sun is 2 × 10³⁰ kg.