Class 11

Physics

Modern Physics

Gravitation

How will you 'weigh the sun', that is estimate its mass? The mean orbital radius of the earth around the sun is $1.5×10_{8}km$.

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

$T =1year=365.25days$

$=365.25×24×60×60s$

$T =1year=365.25days$

$=365.25×24×60×60s$

Universal gravitational constant,$G=6.67×10_{−11}Nm_{2}kg_{−2}$

Thus, mass of the Sun :

$M=GT_{2}4π_{2}r_{3} $

Thus, mass of the Sun :

$M=GT_{2}4π_{2}r_{3} $

$=6.67×10_{−11}×(365.25×24×60×60)_{2}4×3.14_{2}×(1.5×10_{11})_{3} $

$≈2×10_{30}kg$

Hence, the mass of the Sun is $2×10_{30}kg$