Question: is it possible that jupiter is a star? could it become a star and if it did what effect would that have on earth?

Ben Still answered on 18 Jun 2010:

Although it is made of similar stuff to stars, hydrogen and helium, Jupiter is not and will not become a star itself.

The reason is its size. Stars form when masses of hydrogen gas collapse under gravitation. As the gas collapses it heats up. If there is enough gas collapsing then the heat can rise to a temperature where fusion can take place; hydrogen atoms fuse together to create helium and heavier elements.

There is a therefore a minimum amount of hydrogen gas needed to release enough energy to start the fusion process which is the birth of a star. The minimum mass of hydrogen required for this is around 75 times the mass of Jupiter. So Jupiter will always be far too light to become a star.

If Jupiter were to suddenly become a star then the extra local gravity would destroy the orbit of the Earth as we know it, and most probably result in the end of life on our planet. But this won’t happen.