I would not comment on your first question. Even if he arrived at a close result that would be a chance. But I will answer your second question. Vedas are unbroken remembrances of men from pre-glacial times. Aryans, who lived in a sub-polar region where there was a month-long dawn or dusk and a two or three-month night (mentioned in the Vedas as 'Ati-Ratra', during which the Ashvamedha ceremony was held) and had their sacrificial year of nine or ten-month duration (Navagwah, Dashagwah). According to the Parsi Avesta (Parsis were Aryans from India who migrated to Iran because of the heat and fever in the Sapta-Sindhu region, mentioned as their fifteenth home). Aryans had to move out of their homeland because of advent of the ice-age. Avesta also mentions a deluge with a difference, a deluge of snow, where God (Ahur Mazda) warned Yima (King of Men, Indian Yama) and Yima made an enclosure where he saved specimen of vegetation and animals. So, the remembrances in Avesta are perhaps clearer on this point than that of Vedas. In the Hindu story of Manu, water replaces snow because it does not snow in Sapta-Sindhu region. The two books at places are exact copies of each other. The first clear astronomical event mentioned in the Vedas is rising of sun on the day corresponding to Vernal equinox (April 14) in 'Punarvasu' nakshatra. Astronomers have calculated that to have happened in 8,500 years ago. This theory is based on Lokmanya Bal Gangadhar's views on 'Arctic Homes in Vedas' (I could have given you the URL but forum policy does not allow that, you may check on Google for 'Vaidilute', 'Tilak', and 'Arctic Homes').