Give at least two reasons today's astronomers are so interested in the discovery of additional Earth-approaching asteroids.

1. Potential hazard

2. Mining opportunity

Explanation:

The two reason, why astronomers are so interested in the discovery of additional Earth-approaching asteroids:

1. Potential hazard: We have proof that the dinosaurs got extinct because of an asteroid/comet strike on Earth. Also we have seen the effects of the Tunguska event and Chelyabinsk tragedy. These are enough to show us that asteroids can be very dangerous and wipe out the life from Earth.

2. Mining Opportunity: We have discovered a lot of asteroids which contains a lot of metal and precious elements. There can be a possibility of mining such asteroids in the future and reducing the burden on Earth.