Ask A Scientist© Astronomy Archive

Question:  What is keeping us from discovering other solar
systems?
---Steve

Answer:  Their immense distance from us means that their size (as seen from Earth)
is very small. The light from the star is much brighter than any light
reflected from any planets the star might have, so we can't see the
planets directly. We are seeking indirect evidence for other planetary
systems by looking for small variations in the position of the central
star caused by the gravity of possible planets.
hawley