Question

We know the role of the Sun in our solar system and its importance to life on Earth. What would have happened if the Sun were bigger or smaller than it is now?

Answer 1

With that said, we ALL SHOULD KNOW that life on Earth is dependent on the light and heat that it receives from the Sun. If the Sun's mass abruptly halved, it would certainly have a huge impact on these key points; it would grow cooler and redder and eventually transform into a red dwarf.    

or

d If for any reason the Sun shrank smaller than the Earth at least, then this shrunken Sun wouldn't have the mass to create fusion and would burn out completely. Our solar system would lose its only star. ... Earth's mass would be at least 333,000 times bigger than it is now. Imagine the gravity that the planet would have. I think from what i read and learned a bit more of the SUn.!