The gravity of our star reaches out much further, the influence of our sun's gravity goes half way out to the next star which is over 4 light years away. This means that after 2 years of light travel it is possible to find an object orbiting the sun.
I believe we have over 100 planets in our solar system because the bit we regard as the solar system is tiny compared to the reach of the Sun's gravity. Being who I am, I did some maths on my caculator. Let's say we observe 6 hours of light travel as solar system. (1 quarter of a day of light travel). Now the gravity of our sun reaches 2 light years and beyond This means the true area of our solar system is about 3,000 times bigger the observed solar system.
In fact after one day a light photon has travelled 4 times the distance from the sun to edge of the ort cloud. Even if there is just one planet in that space then you have to consider one week of light travel and even one month, then you realise there must be more than 100 planets, some of them would be much bigger than Earth.
Even if some of them were bigger than Jupiter they would be almost impossible to detect because they are so far away.
So much mystery and the mind wonders
