Let's say I prepared an article I wish to publish on my not so popular blog. But I am afraid that this article is so good that much more popular site will steal it and publish it on its own. I am guessing that because of low popularity of my blog, the Google would show links to the bad site instead of my own. Is there a way to prevent such outcome? What if I would prepare an article, publish it on my blog and later decide it it so good that I'll put it on Wikipedia, is there a way that Google would consider me above Wikipedia?
Use rich snippets to markup the article. Add the proper linking to the article in your sitemap. submit/resubmit the sitemap to Google via webmaster tools. Ping the sitemap to google/yahoo/bing. You can choose to publish the article via prweb or other syndication sources so a publication date associated to you is already in the global www record. The best tool you have to establish yourself as originating source to the web is have multiple sources reflect your article and publication/citation date earlier than potential content scrapers or plagiarizers. Article publication and schema is the public facing efforts to do this, the sitemap distribution is the behind the scenes effort to basically create a time stamp record if needed in the future.
On a side note, you cannot prevent plagiarism only take steps to minimize it or overcome it if it happens. Hope this gives you good answers.
Regarding the new comment added by the OP:
1.) Google is an aggregator and doesn't use authorship as a determining factor in SERP's or anything else. Use of Schema markup may improve SERP's only in so far as Google having a better understanding of the contents structure and intentions over other sources lacking proper markup. Otherwise, the issue of "copyright","content creator" and other similar claims falls on the shoulders of a court system, arbitration or just person to person contact and resolution between the claimant and the supposed offenders (plagiarizers or websites lacking proper citation of source).
In so far as forcing any company/person/organization to acknowledge or respect your authorship claims, other than the phone call/email request for them to do so, your only other recourse is legal action in the courts to enforce U.S. Copyright Law probably under the DMCA (Digital Millennium Copyright Act)
In the event that you put your article on Wikipedia you will link back to your original article as a source. (Wikipedia requires sources) Google is not likely to rank your site higher than Wikipedia, but you might find it in addition to the Wikipedia article when searching for it. In addition, your own site will likely be raised in ranking due to the fact that it is linked as a source in Wikipedia.
Also of note is that if your original article is used as a source that means it is credited with being an original.