When is a view 'widely held' in science?

In this week's New Scientist (New Scientist, April 19, 2008) there is a brief column entitled "Moon's birth put Earth in a spin" that includes this sentence:

The moon is widely thought to have formed after an object roughly the size of Mars crashed into the Earth 4.5 billion years ago, throwing up a cloud of debris that eventually coalesced into a rocky sphere.

I don't disagree with this at all. I am peripherally aware of a couple of moon formation theories. I probably could have told you that impact plus debris ejection was a favourite. My question: when is it correct to say that something is "widely thought" in science? Equally, how would one challenge this assertion?

Thesis: a certain absolute number and proportion of relevant scientists, as well as a ranking among competing theories are all necessary, but not sufficient to say that a view is widely held.

Example: If a view is held by less than 20% of relevant scientists in a field, less than a dozen scientists in total, is less popular than two other theories or is less than half as popular as the dominant theory, it is not widely held.

If anyone who reads this thinks that my hypothetical numbers could be improved, can think of another factor that would determine whether a view was widely held or not, or would like to leave some random abuse - please do so! Abuse will be deleted though. Unless it's funny.

The Introductory Post

What is this blog about?

It is about questions. Burning questions. Questions that must be answered. Also trivial questions, poorly posed questions, musings (in question form), questions best left unasked, questions I should have just Googled but posted on my blog instead.

It is about science. It is about truth. It is about logic. It is about intellectual honesty. It is about properly citing sources if I can be bothered.

It is about communication. It is about conversation. It is about exposition. It is about metaphors that stampede across a Jurassic landscape, their bellows resounding in the humid air.

It is about time I stopped rambling. It usually is.

This is of course a vanity blog and I don't intend to do anything except post things which interest me. In many ways this is a trap. I hope lure in unsuspecting commenters from Pharyngula and trick them into writing something insightful.

A warning on structure. I intend to post questions. As I idly come across information which answers a question, I will append it to the post so that the question is incrementally answered over time. I intend to leave a timestamp on each edit for archaeological purposes, but I strongly suspect that this kind of knowledge accretion will make the RSS feed entirely useless for tracking question updates.

About labels. I am going to label questions open questions or closed questions. All questions will start out open, and I will close them when I think they are answered, boring or irrelevant. There is no practical effect from closing a question, it is just a hint as to what I am thinking about lately.