This is one of the best Wikipedia entries I have read yet. Concise and relatively plain English. Clear description of benefits, shortcomings, and possible tests.
I have to disagree, the intro is not very concise, and includes needless details without giving a really clear picture of what the thing is. The parent comment gives a better summary!
Terrestrial testing might be subject to reasonable objections; as one physicist wrote, "Writing the environmental impact statement for such tests [...] might present an interesting problem ..."
