Re: as of now what percent of the universe has been unexplored

Well, in fear of sounding like a not-so-popular politician, the answer to this question depends on your definition of "explored." You see, if you're talking about how much of the universe people have actually set foot on (or come anywhere near for that matter), that's just the Earth and the moon, and that's not a lot. If you're talking about satellites and unmanned spacecraft like that, we've sent at least one space probe out of the solar system and to all the planets except pluto. Now, if you're talking about how much we've seen or mapped, that's still not much, although we have mapped all the cosmic background radiation.

Also, there's a problem with the definition of universe. It is not very likely (though there is a chance) that the universe has a finite end. Although we can find a sort of edge by taking the age of the universe times the speed of light. That's called our "horizon"; it's possible for there to be matter beyond that point, we just can't see it because the universe isn't old enough for light from it to have reached us yet. Soooo, as far as the actual total universe (if it really doesn't have an end) we can obviously never get past 0%.

If you still aren't clear, let me give you an idea of how large the visible universe is, and how much there is to explore. Astronomers estimate that there are 100 billion galaxies, each with 100 billion stars. Thats a total of 10,000 million million million stars. And some stars house solar systems like ours (you know, planets and all that), making the exploration even longer. Now, exploring 10,000,000,000,000,000,000,000,000,000,000 stars is bound to take some time, so even seeing them all with telescopes on land and space is going to take quite a while. So for your answer I'd stick with just about 100%. Hope this helped.