Impacts of cosmic bodies (asteroids, comets) can have catastrophic consequences on Earth. Fortunately, large asteroids, which devastate entire landscapes or continents when impacting on Earth, are rather infrequent, they are mostly known, or can be detected long before the actual impact. However the record of smaller asteroids (<200 m) and meteoroids is incomplete simply because of their large number, and because they are more difficult to detect as they tend to be much fainter. The numerous so-called NEOs (Near-Earth-Objects), which are on Earth-crossing orbits, pose a serious hazard. A well-known example of such an event is the Chelyabinsk meteor that burst in the atmosphere in the morning of the 15th of February 2013 above the Russian city Chelyabinsk. The blast wave generated by the airburst caused severe damage.
Effects of meteorite impacts
The effects of meteorite impacts depend on the composition of the impactor and its trajectory when entering the atmosphere. Large asteroids (>200 m for rocky composition, >50 m for iron composition) with a large impact energy experience little deceleration by the atmosphere and form large craters upon impact with a velocity of several km/s (the typical impact velocity before entering the atmosphere is 18 km/s). In case of smaller objects, depending on the material composition (iron or rock) and the energy of the object, a crater forms, a strewn field of several smaller craters occurs, or the body disrupts in the atmosphere generating a strong blast wave.
Predictions of the effects
When a small asteroid encountering Earth is detected, only little time might be available to predict the potential consequences. Sophisticated simulations of such impact scenarios with the help of computer models are computationally expensive and time-consuming. Such simulations on high-performance computers can last several weeks or months. If time is pressing alternatives are required to initiate mitigation measures. By means of a database composed of simple estimates and a large number of pre-processed simulations of probable impact scenarios the effects can be estimated within a few minutes. The development of such a database is the goal of this project.