Going from today and back in time to the beginning of the universe. The red curve is the difference from now in global average temperature. The blue curve is the height of Solar system above the Galactic plane, showing the crossings with the galactic disk that cause pertubations of the proto-comets in the Kuiper belt and Oort clouds, sending then in towards the inner Solar system and the Earth. The mass extinction 65mill. years ago, marking the end of the Cretaceous and killing off the dinosaurs, happened shortly after such a crossing of the galactic plane, and so did the mass extinctions ending the Permian (251mill. years ago) and the Ordovician (439mill. years ago). The next crossing will happen in about 27mill. years. The Solar system swings about 77 pc above and below the Galactic plane (our Galaxy, the Milkyway is about 100,000pc in diameter).
Suggestions about things to add to the list, are very welcome. Please E-mail contributions to me at
trampeda [at] lcd [dot] colorado [dot] edu
(a short text and the time of the event is all I need).
Enjoy! - Regner
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