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George Jones
Jul23-08, 10:12 AM
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Quote Quote by marcus View Post
I haven't read the paper yet but I will gamble a response to the answer to your question "Is he missing something." Then I'll have a look and see how well my response holds up.

The gist is: It doesn't look to me as if he is arguing that we actually live in a void, or that the Copernican assumption is wrong.

Sounds to me as if he is proposing a nice way to further test the Copernican notion---by raising a question which can be answered by a new bunch of Supernova observations.

The Copernican assumption (that we live in a fairly typical neighborhood) has been tested in the past and has been repeatedly confirmed. In a way, you do a scientific principle a favor by explicitly putting it at risk, because only by being tested can it be confirmed. The more times something is tested (and passes) the more confidence people tend to have in it.

So I would hope that he is not missing anything in his analysis and that the continuing SN IA observations ARE a good test.

But wouldn't it be exciting if it could be determined that we DO live in an unusual neighborhood!
Note: it is "they", not "he". I'm fairly certain that Kate Land is a "she".

Yes, I agree. According to their analysis, observation will soon determine which gives better agreement between theory and experiment, dark energy or a void. This is far different than saying that we definitely live in a void.

The concluding paragraph of the paper:
Quote Quote by Clifton, Ferreira, and Land
Two very different paradigms have been invoked to explain the current observation of an apparently accelerating Universe, depending on whether we invoke or reject the Copernican Principle. We have shown that in the coming years it will be possible to experimentally distinguish between these two scenarios, allowing us to experimentally test the Copernican Principle [26, 27, 28], as well as determine the extent to which Dark Energy must be considered a necessary ingredient in the Universe.