I’m not ashamed to admit it. Remember the movie with the ragtag team of oil drillers who save the planet from a Texas-sized asteroid? I loved it. Sure, it was an absurd premise, but it made for a great action flick.
Hollywood certainly dramatizes the threat of an asteroid impact, but some asteroids are, in fact, potentially hazardous to Earth. Therefore, at FEMA we have to be prepared to respond to them just like any other natural or man-made hazard.
An asteroid impact is not a scenario emergency managers are used to dealing with. They’re more used to things like hurricanes, tornadoes and earthquakes.
Unfortunately, these and other hazards are all too common in the United States, so we have ample experience handling them. We’ve been able to determine the highest-risk areas for hurricanes. We can predict if tornadoes may spawn from storm conditions, and we have the Richter scale to effectively measure and communicate the magnitude of an earthquake.
Since FEMA doesn’t have direct experience with asteroids or their impacts, we’ve turned to some people who do: our partners at the National Aeronautics and Space Administration (NASA).
While FEMA will be the agency in charge of the U.S. government efforts in preparing for and responding to any anticipated asteroid-related event here on Earth, NASA is responsible for finding, tracking, and characterizing potentially hazardous asteroids and comets while they are still in space.
Considering how closely we will need to work together in the event of a potential impact, FEMA and NASA have held three tabletop exercises to work through asteroid impact scenarios and simulate the exchange of information from NASA’s scientists to FEMA’s emergency managers.
I attended the most recent of these exercises on October 25 in El Segundo, California, along with other representatives from FEMA, NASA Headquarters, NASA’s Jet Propulsion Laboratory, the Department of Energy’s National Laboratories, the U.S. Air Force, and the California Governor’s Office of Emergency Services.
In short, the scientifically-realistic scenario we worked through simulated that a fictitious asteroid “discovered” earlier this fall was calculated to have a two percent probability of impacting Earth on Sept. 20, 2020.
The simulated asteroid was estimated to be between 300 and 800 feet (90 to 240 meters) in size and initially has a possibility of impact anywhere on a long, very narrow swath of Earth, including across the United States.
In subsequent years, additional observations increase the probability of impact to 100 percent, and with only a few weeks until impact, the likely impact zone was narrowed to a small stretch of southern California.
While much of FEMA’s emergency management procedures could apply to an asteroid impact, the scenario introduced a few unique challenges.
To begin, the scenario included a two-year span where scientists were unable to observe the asteroid due to its position relative to the sun. Therefore, the threat of disaster looms for a few years before it can be confirmed and long before impact. It’s a complication unlike anything we encounter with other hazards, which we can observe uninterrupted. And while four years sounds like a lot of time between initial observations and predicted impact, even that did not allow enough time in this scenario to launch a mission that could apply enough force to deflect the asteroid (no miracles to save the day this time—sorry, Bruce Willis).
One of the inherent challenges of emergency management is never knowing precisely when a disaster will strike. That’s why I was surprised when the specific date of the possible impact was known immediately following the scenario’s initial observations and long before the location of impact could be determined with certainty. We learned that if astronomers can establish the orbit of an asteroid, they are then able to calculate if and where its orbit will intersect Earth’s. Since we know with great accuracy how Earth moves along its orbit, scientists can then easily determine the date on which Earth will cross the point of intersection. An impact only happens if the asteroid and Earth meet at that point of intersection at the same time.
In addition to the challenges posed by this specific scenario, we also considered that this is just one of a myriad of possibilities for an asteroid impact. Asteroids—especially small ones—can escape early detection, so we must also be ready to respond to an impact without warning.
They may have overdramatized the threat, but Hollywood’s asteroid-themed blockbusters of 1998 did get the basics right: some asteroids are potentially hazardous to Earth and scientists and emergency managers will need to work together in the event of an impact.
We’ve learned a lot about asteroids from our partners at NASA, and while its scientists continue to detect, track, and characterize them, we will prepare to respond to a potential impact, just as we do for all other hazards.