"If humans one day become extinct from a catastrophic collision, we would be the laughing stock of aliens in the galaxy" So says Neil DeGrasse Tyson and I tend to agree.
"Every few decades, on average, house-sized impactors collide with Earth.
Typically they explode in the atmosphere, leaving no trace of a crater.
Once in about a hundred million years, though, Earth is visited by an
impactor capable of annihilating all life-forms bigger than a suitcase."
Saving the planet requires a major effort. We have to catalogue and categorize every object whose trajectory intersects Earth’s orbit then make the necessary calculations in order to predict potential catastrophic
collisions hundreds or thousands of orbits into the future. Meanwhile,
space missions would have to determine in great detail the structure and
chemical composition of these killer rocks.
There are those that would like to blow potentially hazardous rocks out of the
sky with nuclear weapons. Others suggest that deploying a neutron bomb to induce a recoil and alter the asteroid’s orbit is the better solution. A
more practical approach would be to nudge it into a different orbit
with constant low thrust rocket motors such as ion propulsion or by use of a solar sail powered completely by the pressure of the solar wind.