Question

why the asteroid belt offers supporting evidence that the nebular theory of the formation of the solar system is correct.

What are the differences among the three groups known as the Apollos, Atens, and Amors? Which group(s) are we most concerned about?

Answer 1

Nebular Hypothesis: This theory states that Initially the Sun and all the planets of our Solar System are in the form of giant cloud of molecular gas and dust , about 4.57 billion years ago, the cloud to collapsed and this have resulted in the gravitational collapse of the cloud. Most of the dust and gas was collected into pockets of spherical masses and due to pressure these masses heated up and formed planets and the mass at the center became sun.  

But there are certain masses which could not combine to form a planet . One such case is the Asteroids which lie between mars and jupiter. The presence of asteroids show that there really exits a nebula of gas and it collapsed to form solid masses. These asteroids are also in the plain of the solar system. This also acts as a proof for the disk shape of nebula.

Apollos, Atens, and Amors are all near earth asteroids.

Amors are asteroids whose orbits do not cross Earth orbit. These asteroids are the farthest from the sun.

Apollo asteroids have orbits which cross Earth's orbit. They are of intermidate distance from sun. The part of the apollo asteroids orbit which crosses and lies inside the earths orbit is less, so they spend much less time inside the earths orbit.

Atens asteroids also have orbits which cross Earth's orbit, but unlike Apollo asteroids, they spend most of their time inside Earth orbit.

So we should be concerned more about atens asteroids first and then apollo asteroids. As they may hit earth and can cause potential damage