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Re: The Return of The Thagomizer... :-)



Richard W. Travsky writes:
ARGH! Of course. It will continue to get brighter and brighter. The end of life due to overheating is scheduled for one billion years in the future.

So, how much "dimmer" or "less bright" was the sun during the days of
the dinos?


What effect, if any would this have had on dinosaur evolution? Eyesight,
for example?

The sun is thought to be around 4.5 billion years old.


If it started out 70% as bright as it is now, that means it's increased in initial brightness by a further 40% (ie. it's now 140% of the brightness it began at). That's a 1% increase in initial brightness every 112.5 million years on average (assuming a simple linear trend).

If my thumbnail calculations are correct, then the sun has only increased (relative to it's initial brightness) by a further 0.58% since the end of the Cretaceous. Dinosaurs probably lived through less than a 2% increase in brightness due to increased solar output during their entire reign on earth.

Super-volcanic eruptions or major bolide impacts probably had a much greater effect of apparent solar brightness (and in the opposite direction).

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Dann Pigdon
GIS / Archaeologist              geo cities.com/dannsdinosaurs
Melbourne, Australia             heretichides.soffiles.com
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