In the past few years, astronomers have detected many planets orbiting other stars. This led some to wonder what our solar system would look like to alien astronomers on the same quest, using similar technology. They concluded that the key to finding planets around our sun at a distance would be Neptune. This planet's gravity has significant effects on the Kuiper Belt -- the region of gas and dust surrounding the outer limits of our solar system. Christopher Stark of the Carnegie Institution for Science explained:
Through gravitational effects called resonances, Neptune wrangles nearby particles into preferred orbits. This is what creates the clear zone near the planet as well as dust enhancements that precede and follow it around the Sun.
“One thing we’ve learned is that, even in the present-day solar system, collisions play an important role in the Kuiper Belt’s structure,” Stark explained. That’s because collisions tend to destroy large particles before they can drift too far from where they’re made.
Link via Geekosystem