Why do planets shine so brightly

I was outside yesterday and was looked at a really shiny 'stat' so i got my telescope out and turns out it was jupiter ( i think , it had 4 noticable moons around it ) and there was another one just after the sun went down that looked bigger than a star on my telescope but had no moons , so i was just wondering howcome they shine so brightly if on picture's of them from spacecrafts they have there own and not so bright coulers?

Yes, you were most likely looking at Jupiter. Nearer the Sun, in the southwest, was Venus.

Why are they so bright? A couple factors... 1. They are large (in apparent diameter), so they reflect a lot of sunlight. 2. They are quite light in color (they have a high albedo, or reflectance, of incident light). 3. Right now they are relatively close to the Earth, and the reflected light diminishes rapidly with distance (Intensity varies as the inverse square of the distance... twice as far away from your eye yields 1/4 as much light you see.

These are the main reasons.

The published spacecraft images have been adjusted to produce the best contrast, which would make them appear less bright.

The planets shine brightly only because they are so much nearer to us than are the stars. The second planet you looked at (in the southwest) was Venus, which has no moons. It also has a very dense cloud deck, so that all that can be seen of it in amateur telescopes is the phases it goes through similar to those of the Moon. At present it is in the gibbous phase, 83% illuminated, similar to an 11-day-old Moon.

They appear so much brighter than stars because they are much closer - they are in our own solar system.
Jupiter is bright because its huge and has clouds that are fairly reflective.
Venus (the other bright one you saw) is bright because its very close to us and has clouds that are very reflective.