we can't great a natal chart, but we can look at earth chart each year and each moment by calculating a chart for yamakoti which is at 165E46 and 00N00
Without a natal chart, is it possible to figure out the Dasas according to factual information of incidents around the person or planet?
Dasas are not meant to be used for world events.
Its said that vimshottari is the best dasa cause people can live to 120 years, so how long does the earth live? ALso, does earth have repeating cycles of similiar events every 120 and every 360 years? I think it works better to do world events with eclipse charts, new year charts, etc. and transits as we are told to do in the old books.
We can use the yugas cycle of the precession of the equinoxes and we can use the eclipse cycles. we can also use larger cycles of planets being eclipsed, which happens when they join thier nodes such as what happend with Pluto at the beginning of covid.