In the era of dinosaurs, there were no instruments and devices available that could analyse the threat beforehand and find measures to deal with it.
The astronomers suggest that the asteroid belt started as an empty space which was later filled up with the residue or material thrown by outer and inner planets.
The solar system comprises of a star and all the objects that travel around it- moons, planets, comets, asteroids, meteoroids etc. Solar systems can have more than one star called as binary star systems; with more than two stars they are known as multi-star systems.
Our Solar system consists of the stars, the Sun, and all the planets that orbit around it including the Earth. It also includes numerous moons, asteroids, comets, rocks and dust. The Sun is simply one star amongst the hundreds of billions of the stars present in the Milky Way Galaxy.