It wouldn't have much of an effect on the sun, beyond some minor gravity fluctuations and differences in heat/radiation output where the planet crashed (or, more accurately, burnt up). Think of the sun as a house fire, and the planet as a single raindrop -- chances are, that raindrop isn't going to put the fire out (the sun isn't literally on fire, but let's allow some leeway for comparison's sake). Jupiter would be destroyed before it even reached the corona.
Yes, it would affect life on Earth. Jupiter's size and distance influence our orbit, so if it passed close enough, we'd probably be pulled into its orbit as one of its moons. Even if that didn't happen, the effects of Jupiter's immense gravity would knock us out of our current orbit which, again, would interrupt life. It might also affect our rotation and the moon's orbit, both of which help to stabilize our planet.
In short, it would suck for us if Jupiter hit the sun, but the sun itself would be fine.
· 1 decade ago