a device called a super telescope was used in an air craft 1.5 million miles away from earth to look farther
Planets orbit stars, stars orbit a galaxy. Planets are not "on" anything. A lot of stars out there have planets - we are just finding out how many now that we have better techniques to find them. So probably all galaxies have at least some stars with planets.
extra solar planets are not bright compared to the stars they orbit
Planets are not active emitters of energy, that would be Stars. Planets only reflect the energy (light) from nearby stars that they orbit. That is what makes it so difficult to find planets outside of our Solar System.
Light from the stars they orbit makes it difficult to see them.
Hundreds of billions of stars, some of them with planets.
Perhaps orbiting around other stars, but we have yet to find them.
microlensing
nothing important
Why the planets stayed int their orbit.
You can find Planets, Billions of Stars, and Comets, meteoroids, comets, black holes and alot of other stuff.
The best possible answer is we don't know.Just a decade or so ago, astrophysicists believed that no other stars have planets. The first exoplanet discovered was Gamma Cephei b, in 1988. While its existence was questioned for more than a decade, it was finally proven in 2003.There are currently 840 Planets around 655 Stars, 128 of these are in systems with multiple planets; there are 2,712 Kepler candidates, and 2,756,217 Transit Survey Light Curves that could prove to be exoplanets as well.
Its most likely that they do. Any planet with an axial tilt will have seasons throughout its orbit. Eclipses of orbiting moons are also likely to occur on these exoplanets, though it would be rare to find an orbiting moon that is almost the same apparent size as the star - as with Earth.