Can We Prevent a Killer Asteroid Striking Earth?
By Dr. Gary Deel
Faculty Director, School of Business, American Military University
This is the first of two articles examining the existential threat of a major asteroid collision with the Earth. Check out part II here!
Humanity faces a variety of existential risks on a daily basis. Terrestrial natural disasters such as volcanoes, earthquakes, hurricanes, and tornadoes claim the lives of roughly 60,000 people every year. And a major disaster – such as a supervolcano eruption – could threaten the continued existence of mankind altogether.
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Then there are human-created threats like that of nuclear war. It is well within our power for us to destroy ourselves. Weapons of mass destruction will never be uninvented, and if we don’t take proper care with these responsibilities then it is entirely possible that we could bring an end to our own civilization through tribalism or stupidity.
However, one of the most significant and best understood – but least predictable – risks is that associated with the possibility of an asteroid striking the Earth
In the early development of our solar system, collisions between asteroids and celestial bodies were fairly routine. We see clear evidence of this in the preserved craters that pockmark the moon’s surface. In fact, a prevailing theory of the Moon’s origin is that it is the result of some kind of asteroid impact.
The Moon Was Formed by a Violent, Head-On Collision between the Early Earth and a ‘Planetary Embryo’
According to UCLA geochemists, “the moon was formed by a violent, head-on collision between the early Earth and a ‘planetary embryo’ called Theia approximately 100 million years after the Earth formed.” The collision would have blown all of the crustal material from both Earth and Theia into space.
It is postulated that the moon might have accreted from this material over the eons that followed. “Theia, which did not survive the collision (except that it now makes up large parts of the Earth and the Moon), was growing and probably would have become a planet if the crash had not occurred,” the UCLA scientists postulated.
We have more historical evidence of significant impacts on Earth. The largest known impact site is the Vredefort Crater southwest of Johannesburg, South Africa. It is more than 186 miles (300 kilometers) across and is believed to have been created by an asteroid that was roughly 6.2 miles to 9.3 miles (10 to 15 kilometers) in diameter. Although this event occurred over two billion years ago, it would have had tremendous effects on the Earth and any living thing thereupon at the time.
Another major and more recent historical event was the impact that formed the Chicxulub Crater, which lies buried under the Yucatan peninsula in Mexico. This crater was formed about 65 million years ago, coinciding with the extinction of the dinosaurs.
These Impacts Would Have Wiped Humanity off the Face of the Earth
These impacts would have wiped humanity off the face of the Earth had we been around to experience them. It might be tempting to think that such events are rare; on the timescale of a human life span, they certainly are. But in the context of the 4.5 billion-year evolution of the Earth, we know from geological evidence that these impacts happen at an imprecise but fairly regular frequency. That said, there is no reason to believe that another such cataclysmic event will not occur in the future, or in the near future for that matter.
It Is Important that We Plan Properly for the Inevitable Asteroid Strike
It is therefore important that we plan properly for the inevitable. The first step is to create a robust monitoring program to watch the skies in order to detect potential threats as early as possible and coordinate an adequate response effort.
I have written of the dangers associated with the possibility of an asteroid impact, the current state of NASA’s Near-Earth Object (NEO) search program, and the need to better fund our search efforts so that we can address any major threats before it’s too late.
In order to address the most severe risks, Congress has tasked NASA with finding all NEOs that are 460 feet (140 meters) in diameter or larger. To date, NASA has identified more than 22,000 such objects. Fortunately, none appear to pose a threat of striking the Earth anytime soon.
However, cosmologists and other experts estimate that the current catalog of known asteroids accounts for only about 25 percent of all such objects in the solar system. This means that almost 70,000 more NEOs of this size remain to be found. It seems we still have quite a long way to go before we can safely say that we have a firm handle on this threat.
Assuming we’re able to identify the next potential impactor with enough advance notice to take appropriate steps, the big question is regarding what steps we should take.
Calculate where the Asteroid Is Expected to Strike and Evacuate the Area
One obvious measure would be to calculate where the asteroid is expected to strike and evacuate that area. However, such an evacuation might prove impracticable or impossible depending on the size, speed, and location of the asteroid’s projected impact.
For example, if a large, fast-moving meteor were to plunge into a major ocean, it could create a mega-tsunami that would spread in all directions, striking every coastline in its path. Such a tsunami wave could be hundreds or even thousands of feet high and could travel many miles inland. Evacuating the populated coastlines around the world is probably not feasible, and certainly would not completely ameliorate the harm.
So, is there anything we could do to completely avoid such an impact? Fortunately, many scientists agree that it might be possible to deflect an asteroid and prevent it from hitting the Earth altogether. That is if the circumstances are such that we have enough time, money, and ingenuity to meet the challenge.
In the second part of this series, we’ll examine a shortlist of some of the best ideas that experts have put forth to deflect or divert an asteroid on a collision course with Earth.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a JD in Law and a Ph.D. in Hospitality/Business Management. He teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.