If I know specific time, t0, how can I calculate RA of Greenwich?
Why does Mars' experience an 'ice age' at high axis obliquity, when Earth experiences an ice age at low axis obliquity
This paper here goes into some detail about how Mars' experiences its own form of 'ice ages' on a quasi periodic basis driven by the wobbling of its axis. The main mechanism outlined is that the ...
In the National Geographic article: http://news.nationalgeographic.com/news/2009/04/090403-gamma-ray-extinction_2.html it is suggested that a gamma ray burst likely caused a mass extinction in earth's ...