The Faint Young Sun Paradox: 3 Solutions?

The snow surface at Dome C Station, AntarcticaFor the Wednesday news article Tim Clarey writes Sun Paradox Challenges Old Earth Theory.

To recap, the faint young Sun paradox comes from an apparent contradiction between observations in the fields of astronomy and geology. On the one had we know that many stars on the “main sequence” get hotter and brighter as they age: the Sun appears to be on the main sequence, and so a couple of billion years ago in the Archean it would have only around 75%-80% if its present output. Reduce the Sun to that level now and Earth would freeze over.

On the other hand the geological record of the Archean is sketchy at best, but evidence from fossil cyanobacteria (blue-green algae) and raindrop imprints show that there was at least some liquid water somewhere on the planet at this time. There were some glaciations at the end of the period, but clearly not throughout.

A paradox then, and one that creationists are predictably fond of. Continue reading

The Faint Young Sun Paradox

If our Sun is, as we believe, a perfectly normal 4.5 billion-year-old main sequence star, we would expect that, say 3 billion years ago it would be largely the same as another main sequence star of that age. And, 3 billion years ago, we would thus expect that the sun would output around 70% of the energy it does today. Unfortunately, this is too little to sustain liquid water on the surface of the Earth. And yet, we know that there was.

This, then, is the faint young Sun paradox.

The Sun, through a telescope (a bad idea, but somebody managed it...) Continue reading