Science for Thought

Asteroid Dangers

Asteroid Dangers

Are we doomed like the dinosaurs? Does humanity have a means to escape their fate? Approximately 66 million years ago, a huge asteroid collided near the Yucatan and killed off the dinosaurs. It didn't happen immediately, but the devastating effects of the asteroid eventually destroyed them.

One thing that's helping us is that there are many astronomers searching for dangerous asteroids that are on a possible collision course with Earth. They're using wide imaging telescopes to search for objects moving across the fixed stars. Then it's a matter of doing calculations to determine the chances of it hitting Earth.

Radar is another method to see asteroids and determine their shape and what they're made out of. This is crucial because iron asteroids are far more dangerous than rocky ones. Also, many asteroids are made out of rubble, which is small debris that's held together by gravity. If one of these hit the Earth it would simply result in a shotgun blast instead of a single solid shot.

The answer is that we need Bruce Willis. Just kidding! Actually, there are ways that we could mitigate an apocalyptic asteroid collision.

What methods could be used?

Use a nuclear device near the asteroid to push it off course. The problem with this idea is that it has diplomatic issues. It also requires exact positioning and distance.  A nuclear blast in space is not as effective as it is on a planet.

Use a spacecraft to employ kinetic impact as a means to move the asteroid off course and avoid a collision with Earth. This idea has already been tested in the lab, and there is a mission to do the same thing as a real test. The reason why asteroids venture into the Earth's orbit is from collisions in the asteroid belt. The impact method would work for mostly rocky asteroids.

If the asteroid is denser than a rocky asteroid (made from iron) then it must be knocked off course using a powerful laser beam. Light has momentum and can exert force, especially if it has high energy. The Sun exerts force by heating objects like asteroids up on one side allowing infrared photons to act as a propulsion force. It's not a large amount of force, but over time it will change an asteroid's course. What has to be determined it the absorptive color of the asteroid and how it's rotating. The space laser idea is actually being tested.

Use gravity to move a rubble asteroid off course. This would require sending a spacecraft probe and allow it to tug the asteroid into a safe orbit. This requires keeping the probe from being attracted into the asteroid. This idea requires that we know the asteroids exact course and the influence of Jupiter and the Sun.

The problem with all of these methods is that none of them are ready to go. We need time to develop and test them. This is the reality that concerns me, especially considering how governments procrastinate in the face of threats.

We do have protection against smaller asteroids. The atmosphere burns up small asteroids every day and every so often we see a very large asteroid burn up as a fireball. These can cause damage if they break up and explode. Large asteroids that cause fireballs hit the Earth every hundred years. These are only rubble or rocky asteroids that do this.
However, if an iron-based asteroid comes into the atmosphere it will cause an enormous crater. If such a dangerous asteroid hits in the deep ocean it will cause a tremendous tsunami but will not destroy all life on the planet as it would if it hit on land. It will possibly destroy ocean front structures, depending on where it hits.

A football stadium sized asteroid hits the Earth every few thousand years. This size would also cause a lot of damage, but in the deep ocean an asteroid like this would not cause a huge tsunami because of the dampening effect of shallow water on the continental ledge. However, it could hit on land and destroy an entire city.

We need to get ready for these cataclysmic events. Bruce Willis may not be around when it happens.

Thanks for reading.