There's really no point in either. A radio signal would need to be extremely powerful to travel 500 light years without degrading (not to mention that even the

There's really no point in either. A radio signal would need to be extremely powerful to travel 500 light years without degrading (not to mention that even the senders may not be able to decode it after 1000 years :-)), and sending spacecraft to navigate 500 light years hoping it will perform all maneuvers correctly and not get hit by something in order to reach a planet without being able to send any useful information back seems naive and pointless. If there's any space faring civilization out there, they're probably content with their own star system and maybe the ones closest to it - there are so many planets and asteroids to mine for resources (plus recycling would be a big thing) they could last for hundreds of millions of years...