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

Given that

Orbital radius, r = 1.5 × 10⁸ km

= 1.5 × 10¹¹ m

We know that, Time for one revolution = 1 year

= 365.25 × 24 × 60 × 60s

Now,

M = \(\frac {4π^2r^3}{GT^2}\)

G is universal gravitational constant.

⇒ M = 

= 2.005 × 10³⁰ kg

≈ 2 × 10³⁰ kg

The estimate mass of sun is 2 × 10³⁰ kg.