Asteroids, comets, and a tsunami that ran up Lake Geneva in ad563

30 Oct 2012

At http://phys.org/print270613694.html ... a conference at Orlando in Florida next february, on comets and asteroids, is timed to coincide with the flyby of asteroid 2012 DA14. This will pass as close as 14,000 miles to the Earth. NASA has identified 4,700 objects as potential threats to the Earth.

At http://phys.org/print270653941.html ... a tsunami wave generated across Lake Geneva around 1500 years ago, in the 6th century ad, is the subject of an article in the current issue of Nature Geoscience. An estimated wall of water some 42 feet high was created by a land slip. A French bishop, the well known Gregory of Tours, has left behind a description, of sorts, recording the destruction of villages, farms, and farm animals along the coast of the lake, the water also rising above and over the town walls of Geneva where several people are recorded as being drowned in the process. The land slip left behind a huge heap of sediment, 6 miles long and 3 miles wide, and it was this, falling into the lake, that generated the destructive wave. The estimated age of the sediment and debris is between 381 and 612ad. The account by Gregory of Tours is dated at 563ad - hence the date in the headline. What caused the land slip is not mentioned in the abstract but a few years ago a cosmic object was being blamed - but was debunked. One factor in the success of the debunking was the date applied to the land slip - it didn't match. Now it might do (but having said that the land slip could have been caused by a variety of factors from earthquake to slippage between one geological layer and another but this is not of course as exciting as a cosmic object).