is it possible that the sky is black because theres a giant planet that doesn't let any light thru?

First, explain how your idea fits in with day time.

Secondly, it would take one enormously huge planet to block out all light. You fail to take into account of the gravitational effects of such a huge planet.

The reason space is dark is that there are too few light sources too far apart to light up space.

Depends on the time of day. 

No, its not possible.

The sky is not black, stars and other objects are quite visible in the sky.

Well... if you're referring to "night", then if the planet was further from Earth from the sun - then, we'd see it's face completely illuminated (like the full moon). Otherwise, the sky is place because our eyes can't detect photons coming in from very distant stars and galaxies.

No,

it's black because space is huge, and light emitting objects (stars) are few and far between,.

No. The sky is black because some of the light sources are moving away from each other too fast for the light to reach us.

anything is possible,but its probably nighttime where you are

No because there is just not enough light from the stars and moon to make it not black