Galaxies are tens or hundreds of thousands of light years across, and they emit their own light.

Pluto has a diameter of 2274km and is so far from the sun that it can barely reflect any of that light back to us.

The New Horizons space probe will be at Pluto in a few years, something to watch.


[edit on 2/6/2010 by ZombieOctopus]

Like ZombieOctopus pointed out, even with the best of our telescopes, we;'re basically looking at a pebble in a dark closet. No matter how much we work at it, it's going to keep on looking like a sad lump of blurry, until we're right next to it.

Here's another way to look at it, using high-school trig:

Say Hubble can see a galaxy 100,000 light years across and 10 billion light years away. The angular width of that galaxy would be ~2 seconds of arc (1 second of arc is 1/60th of 1/60 of a degree. The full moon is ~1/2 degree or 1800 seconds of arc).

Pluto is 2274km across and 4.48 billion km away. Its disk subtends only 0.1 seconds of arc, or 1/20th of the apparent width of a galaxy 10 billion light years away.

That is why it is so hard to resolve any detail on Pluto's surface.