If there were any dinosaurs around, they could tell you that an asteroid impact can ruin your whole day. But if we did learn that one was actually going to strike the Earth in a month, what would the authorities do? To find out, the European Space Agency (ESA) held its first ever mock asteroid drill to work on solutions and identify problems in how to handle such a catastrophe.
What the effect of an asteroid hitting the Earth would have depends on a number of factors, such as how big it is, what it's made of, how fast it's traveling, and where it hits. This means that an asteroid could end its career as nothing more dangerous than a shooting star, or it could wipe out all life on Earth.
Needless to say, the folks at ESA’s Space Situational Awareness (SSA) program aren't worried too much about either of those extremes, but the ones in between that can and have caused real damage, such as the 2013 Chelyabinsk event, where a 19 m (62 ft), 3,300 ton meteor exploded 25 to 30 km (15 to 19 mi) over Russia with a force of 480 kilotons, injuring 1,500 people and causing millions of roubles of damage.
That was a near miss, but a direct hit on a populated area would have been far worse. The question is, how would foreknowledge help and what can be done with it?
In November, ESA gathered experts from national disaster response organizations in Germany and Switzerland for a two-day mock alert involving hypothetical asteroids of various sizes ranging from 12 to 38 meters (40 - 125 ft) in diameter, or about the size of the Chelyabinsk meteor and the object that hit Tunguska, Siberia in 1908.
The experts were formed into teams and asked how they would respond to an impact with warnings ranging from as much as 30 days in advance to as little as one hour. The differences in sizes and warning times dictated what the authorities could do, how the information would be distributed, and to whom it would go.
"For example, within about three days before a predicted impact, we’d likely have relatively good estimates of the mass, size, composition and impact location," says Gerhard Drolshagen of ESA’s NEO team. "All of these directly affect the type of impact effects, amount of energy to be generated and hence potential reactions that civil authorities could take."
The drill demonstrated that ESA would be able to provide authorities with information about a possible impact, its severity, and recommended responses. These might range from a full-on relief effort to something as simple as warning people to stay away from windows or seeking shelter as if from severe weather.
One notable finding was that problems were also discovered, such as the need to learn what the requirements of local governments are, drawing up timetables for disseminating information from SSA, and the need to coordinate with international bodies like the UN for global responses.
ESA says that it plans to hold more such drills in the future with one scheduled for next year that will include more countries.
"There are a large number of variables to consider in predicting the effects and damage from any asteroid impact, making simulations such as these very complex," says Detlef Koschny, head of NEO activities in the SSA office. "These include the size, mass, speed, composition and impact angle. Nonetheless, this shouldn’t stop Europe from developing a comprehensive set of measures that could be taken by national civil authorities, which can be general enough to accommodate a range of possible effects. The first step is to study NEOs and their impact effects and understand the basic science."