Why do planets orbit stars?

1 Answer
Apr 15, 2018

There are two ways of explaining this phenomena :-

Explanation:

#1) # Newtonian Gravitational theory :-

A Planet revolve around a Star because of the mutual gravitational interaction between them and this force is given by #F#

#{F=(GMm)/r^2}#

where #M# is the mass of the star

#m# is the mass of the planet

#r# is the distance between their centres

#G# is the Universal Gravitational constant

https://www.quora.com/What-is-the-force-responsible-for-the-revolution-of-planets-around-the-sun

#2)# Einstein's General theory of Relativity :-

This theory tells us that the Space-Time is like a piece of Fabric and the mass of an object causes to bend the curvature of Space-Time around it. And more massive the object is , the more space it bends around it.

So, in case of Star and a planet , since the star is more massive ; so it bends the space around it much more than the planet does ; which causes the planet to be in a state of falling towards the star ( just like gravitational interaction) which causes it to orbit the star.

https://www.science.org.au/curious/space-time/gravity

http://78.media.tumblr.com/661bbcdbb17ef9102b4c132ef0b0ebf2/tumblr_inline_nx566mrmW91srob4n_400gif