On a clear night, we can see a sky full of stars, some of which are their own glowing stars, and some of which are planets that don't glow but reflect light from nearby stars  Stars may be distant, but some can be seen by existing optical telescopes
Unlike stars, most extrasolar planets cannot be seen with existing optical telescopes because they emit no light and are much smaller than stars
Extrasolar planets are so far away that they rarely reflect light from their stars back to Earth.