On 30 June 1908, and drew a big explosion in a remote area in Siberia during the 2000 km2 of the surrounding forests, but there was no impact crater to be found. One of the leading theories when the strange ship exploded, fueled by science fiction novels of the time and that several witnesses claimed that the object that exploded as a "big pipe."
One would expect that if involving a spaceship to explode, there are certainly some of the wreckage were found at the site, but have found nothing so far. Also, if some kind of explosion of a nuclear reactor, and then covered the area around the radioactive dust, but detected no abnormal radioactivity in the region. But you also need to consider: civilization advanced enough to send the vehicle light-years distant in space and can also develop forms of energy that does not leave behind radiation.


