Getting harder and harder to figure out which side has the more fantastic explanation.

It's hard to tell from this article exactly what's going on (science reporting is really, really bad), but at first glance there's nothing fundamentally new here. The only potentially new thing is that it sounds like Schaefer is using gamma ray bursts as standard candles, which would allow him to look back further than can be done with supernovae. However, the notion that "the force dark energy exerts may have varied over time" was pretty conclusively demonstrated back in the winter of 98/99.

I suspect we are seeing a repetition of the problems Edwin Hubble encountered in his initial program to determine the Hubble constant. As b intimates, astronomers need objects of known luminosity (standard candles) for absolute distance determinations, which are then compared to the red shifts of the objects. It took decades to sort this out and there were many revisions until they found a consistent set of objects to use.

All of this depends on the assumption of uniformitarianism, that the nature of these objects has not changed over time and we haved correctly identified them. But there is some evidence that the early universe was not like the current era (e.g., quasars). It is thus possible that changes in the cosmological constant are the result of the changing nature of objects, not a variation in a "dark energy" force.

Posted by: jd watson at January 12, 2006 2:03 PM

There is a "constant" beneath the lowest turtle.