Impacts on Earth from Small Solar System Bodies


Dr. Aswin Sekhar

Centre for Earth Evolution and Dynamics



The danger to Earth because of impacts from asteroids and 
comets is receiving a lot of attention in present times. Coincidentally 
when this abstract is being prepared, there is a close approach of 
asteroid 2013 TX68 approaching Earth within a distance lower than the 
geostationary satellites. The recent spectacular fireball on 2015 Mar 15 
over Switzerland got widespread media attention in Europe. The 
remarkable event on 2013 Feb 15 over the Russian city of Chelyabinsk 
boosted public awareness of the importance of threat analysis on the 
bodies from outer space. The pathways by which these dangerous bodies 
arrive at our planet are the same as those of the benign shooting stars 
(they originate from comets or asteroids) we see every night. The 
difference is only one of scale, between a romantic flicker of light on 
the sky and a dangerously explosive case such as the Chelyabinsk event. 
Various telescopic surveys and observational databases are able to give 
rough estimates of size frequency distribution for Earth impacts and 
they help in calibrating the risk level to a certain degree. In this 
talk, the aim is to give a brief background into the calculations 
concerning various scenarios of Earth impacts. The idea is to present 
some analytical, geometric and numerical approaches which help us to 
assess the possible dynamics of impacts on Earth. Some very simple to 
not-so-simple cases would be presented so that one gets to understand 
how the nature of calculations can get tricky as one broadens the scope 
of studies with different classes of bodies in their past, present and 
future evolution in our solar system.

Published Jan. 27, 2016 11:24 AM - Last modified June 28, 2016 3:50 PM