Accidents and asteroids: an interview with Alan Harris
It was February 15, 2013 when the biggest explosion in the Earth since the 1908 took place over the city of Chelyabinsk. According to Alan Harris, Senior Scientist at the DLR Institute of Planetary Research in Berlin «It was a pretty nasty event, […] it just shows the sort of force that these things have». Every day NEOs hit our planet but, fortunately, without representing a concrete threat. Thanks to the establishment of a group
Chelyabinsk: one year later
The best estimate for the mass of the object is accepted to be around 10.000 tons. The object entered our atmosphere at an incredible speed of 19 km/s releasing about 500 kilotons of energy. It is classified as an ordinary chondrite of the type LL5. After the explosion most of the object became dust. Only small fragments made it to the ground. First studies of material samples found suggest the age of the object to
Collision in our planetary system: it started with an event on Jupiter
The direct observation of impacts in our planetary system started in 1994 when astronomers could directly observe the impacts of cometary fragments on Jupiter: the newly discovered comet Shoemaker-Levi was caught by the large gravitational field of Jupiter. First its orbit was changed. Later Jupiter´s gravitational forces became larger than the inner stability of the comet which resulted in a break-up of the comet. Since that a planetary pearl necklace approach Jupiter and finally impacted.
Recent collision in our planetary system:about recent cratering on Mars
A relatively large crater was suddenly detected by the NASA Mars Reconnaissance Orbiter (MRO) on the surface of Mars. This exciting discovery was made by the High Resolution Imaging Science Experiment HIRISE which saw for the first time an about 30 m diameter crater in the center of a colorful radial burst pattern. This crater appeared obviously in the time between July 2010 and May 2012. Based on apparent changes between those before-and-after images at