Asteroid impact is one of the greatest threats to humanity and life as we know it. In the early years of Earths formation, large scale impacts were quite common. Much further into the future a giant asteroid collision caused the events that lead to the death of the dinosaurs. With such precedents it’s reasonable to assume that it could happen again. So Should you be worried?

First of all, it’s important to distinguish what counts as a threat. The Earth is bombarded with tiny meteors every day that burn up harmlessly or cause small amounts of damage. We’re not concerned with these. As with everything size matters, and we need to know how big an asteroid needs to be in order to be a concern.

NASA’s Jet Propulsion Lab states that any space rocks smaller than 25 meters burn up in the atmosphere. Meteors between 25 meters and 1 kilometer would cause “local damage to the area.” Finally meteors larger than 2 kilometers would cause “Worldwide Effects.”

So, what does “local Damage” and “Worldwide Effects” entail? It’s obvious that the agency is trying to be very sterile in their word choices and not inspire unneeded panic, but the reality of those terms are quite grim. The Hiroshima and Nagasaki atomic bombs caused “local damage.” I think we all agree that something of that scale or bigger is a serious problem.

Can We Prevent an Asteroid From Hitting Earth?

Luckily yes! There are many ways we could destroy, or deflect a dangerous asteroid. All of which have varying degrees of effectiveness depending on the size, course, proximity to earth, and time before impact. There is no reason that with our current technology, we couldn’t prevent any giant asteroid from hitting Earth.

In case you didn’t get the memo, space is really, REALLY BIG. Meaning that Earth is a really small target in comparison. Therefore, to detect a dangerous asteroid we would only need to change its course a tiny bit, which over its millions of miles journey would result in it harmlessly whizzing by earth.

Do We Have Any Plans Set Up Now?

Unfortunately no, not really. Currently we have no measures in place to destroy or deflect hazardous Near-Earth Objects. Despite there being many different ways we could. That isn’t to say that people aren’t trying. It’s just very difficult and expensive. Public support and political attention are very important on these issues.

There is good news from the private sector though, as SpaceX has been contracted to launch the DART (Double Asteroid Redirection Test) aboard one of their falcon 9 rockets. This mission will test the ability to deflect and change the course of two asteroids. It’s a valuable proof of concept which will be used to gather data for the “Kinetic Impactor” plan to deflect asteroids. That is to say, hit it with a big weight. Not fancy but it doesn’t really need to be. It’s the first test to establish a more concrete asteroid prevention program.

Spacex Falcon 9 rocket. The rocket that will test Giant asteroid contingency plans.
Image courtesy of SpaceX

So Do We Know of Any Asteroids That Will Hit Earth?

Currently we have not detected any dangerous asteroids that are on a collision course with Earth. So feel free to take a moment to relax and take a few deep breaths. Even though we have no operational asteroid deflection systems, NASA is constantly tracking and cataloging as many near-earth objects as they can. When an asteroid is detected they assign it a threat level.

This threat level is called the Torino Scale. It scales from 0 to 10, with 0 being the least dangerous and 10 being the most. The scale considers the probability of impact along with the destructive power of the object. Since its implementation no object has ever been rated higher than a 4. Currently there are no objects rated higher than 0 as all objects with higher ratings have been reassigned to threat level 0 as more research has been conducted.

Asteroid Impact Torino Scale
CC BY-SA 3.0,

Although NASA has made great strides in identifying near-earth objects they’re far from detecting them all. The threat of giant asteroid impact does still exist, but luckily the larger the object the easier it’s to detect. This means that the chances of an undetected giant asteroid hitting earth are very low. Yet any support or resources given to them contribute to that number shrinking further.

So Why Have I Been Hearing About Asteroids Lately?

There are a couple different reasons. Recently NASA has conducted some asteroid deflection drills and simulations to see how well we could respond to an asteroid in a short time period. While They were very thorough in stating that it was a drill, the media was not. They saw fit to use the test to draw attention and clicks. Admittedly I’m not free of blame either. I wrote this post to answer all the questions that I myself had and put them in one place, yet I too knew that the subject matter draws a lot of attention.

Along with the asteroid drills there have also been several influential figures drawing attention to the matter, namely Neil deGrasse Tyson, and Elon Musk. They both have vested interest in drawing attention to this subject and saw fit to highlight our lack of a contingency plan. This is true, but perhaps was more alarmist than it needed to be.

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