Tony,
This reply will be a little long, but I'd like to give you the best answers I can, since I'm the author of the piece on Jenkins and his vampires.
You wrote
From what I see on the internet, Jenkins is the only proponent to provide facts and evidence to support his theory in MC 2012. After surfing a little on the internet, I can't figure out what he is actually saying will happen on Dec. 21 2012.
You're not alone. When I talk to Jenkins supporters, they usually say something like, "He's so amazing, and he backs everything up with research, but I can't understand it." However, I'm sure you'll agree that without understanding what he's saying, there's no basis for saying that his research really supports the conclusions he draws.
That's why I put a series of videos on YouTube about the astronomy of 2012. They're intended to let folks like you learn the astronomy needed to decide for yourselves what Jenkins is saying. The three most important videos are
http://www.youtube.com/watch?v=Y0ggs4fOUhc,
http://www.youtube.com/watch?v=jUhq54jrKo0, and
http://www.youtube.com/watch?v=unuAu9_fW9o.
The complete playlist is at
http://www.youtube.com/view_play_list?p=CA20FB1DCA9C7DFF .
I'll be happy to answer any questions you might have. But to save both of us some time, please view all of the videos before you ask me. The whole series takes about an hour. (I'd guess you've already spent more time than that, surfing the web to understand Jenkins.)
You had a question, which I understood to be
Most [web] pages say that [Jenkins] says that the Mayan's understood precessions and equinoxes and the long count was intended to alert our civilization. Alert us of what, exactly?
I'll address that question near the end of this post. First, I want to explain why Jenkins' bizarre accusations against detractors like astronomer Stephen Tonkin are relevant to that question. Before you continue, you may wish to open another window in your browser, and go to the Jenkins' description of their exchange of emails:
http://alignment2012.com/tonkins-error.html.
Near the end of the introductory sentence, you’ll see Jenkins assure us that he conducted the exchange “with clear diplomacy”. Which he undeniably did: Jenkins' opened the exchange by diplomatically informing Tonkin that
“[W]ith a smugness borne of the superiority complex of many scientists, [you say] something with authority that is actually completely wrong!”. (Emphasis in original.)
Before continuing, we need to realize that astronomers are, in effect, a “tribe”, with its own language (i.e., “astronomical terms”). That tribe has a “culture” that includes, and provides the context for, the proper usage and interpretation of those terms.
If you now read, carefully, the exchange of emails between Tonkin and Jenkins, you’ll see that Jenkins –an outsider to that culture— was demanding that Tonkin (a member thereof) accept Jenkins’ own use of the term “conjunction”, rather than the culture’s own. At first, Jenkins demanded this out of ignorance. By the end of their correspondence he was demanding this knowingly, and very “diplomatically”.
Tonkin, having already pointed out that Jenkins’ misuse of the tribe’s language gave Jenkins’ statements a bogus air of legitimacy, finally told Jenkins to get lost.
This is the exchange to which Jenkins and his friend Jonathan Zap responded with accusations that Tonkin has a “brittle neurotic power complex”, and an ego that’s “playing masturbatory games with itself”. (Follow the “Zap’s Comments” link http://alignment2012.com/zap-on-tonkins-error.html at the end of the Jenkins’ article.) Jenkins and Zap not only made such accusations on line; they repeated them five years later in The 2012 Story (pp. 232-233, 441).
So, what’s the relevance of all this? Jenkins’ insistence upon using the “astronomy tribe’s” language as he pleased is grounds for questioning whether we can trust his “insights” into cultures that have no living members around to correct him.
Finally, back to your question,
Most [web] pages say that [Jenkins] says that the Mayan's understood precessions and equinoxes and the long count was intended to alert our civilization. Alert us of what, exactly?
To answer that question, we have to back up a step, and address its underlying assumption:
"A major cycle of the Maya calendar completes on 21 December 2012. There must be some reason why the Maya selected that date."
That assumption is actually three-fold:
The Maya selected that date.
Actually, this assumption is disputed: some scholars say that the Maya selected 23 December rather than 21 December.
The Maya selected that date.
“The Maya” were not a homogeneous group, so we don’t know exactly who came up with the calendar. This also means that we don’t know which group’s beliefs are reflected in the selection of “that date”. Which brings up the third assumption:
The Maya selected that date.
This, too, is in dispute. Did the [whoever] select the end-date of the calendar, then back-calculate the start date, or vice-versa? Or are both dates unimportant consequences of basing the calendar on some other reference date(s)?
Sorry to give such an anti-climactic “answer”, but I’m afraid it’s the best that can be given. "What the Maya alerted us to" (if anything) seems to be anyone's guess. Jenkins’ home page (http://www.alignment2012.com) seems to bear me out.
To see this, please read the blurb on that page for the upcoming 2012 Tipping Point Prophets Conference. Next, read Jenkins’ own section entitled “What the Maya Left Behind”. Please note, too, that Jenkins is one of the Prophets. (http://greatmystery.org/events/vancouver2012faculty.html)
Putting all this together, doesn’t it seem that according to the Prophets themselves, discussions of “2012” are just radical modern-day interpretations of what the Maya might have been referring to when they recorded what they suspected 2100 years ago?
Of course, we shouldn't put words in the Prophets’ mouths. Therefore, I've emailed this same question to the conference directors. I'll let everyone know what answer they give.