Harvard Astronomy students can describe their thesis work in writing, for example following one of the models listed below.
This writing should be made permanently available online, for example through a Wordpress or Blogger site, or through publication in an established outlet. A possible outlet for this is Astrobites; please contact an Astrobites author at Harvard to inquire.
PhD Outreach Example: Thesis Chapters for the Public
UW Madison encourages their chemistry students to write a Ph.D. thesis chapter explaining their research to the public. Past examples are listed on their website. The best examples of these show how a graduate student can describe their research in accessible terms in an essay format. For example, see the chapter by Jason Russell (2012).
These sample blogs would not fulfill the PhD Outreach Requirement. However, graduate students are well served by maintaining a blog.
General Outreach: Blogging the Standard Model
Cornell physics grad student Flip Tanedo has written a series of blog posts for Quantum Diaries explaining how to read Feynman diagrams and understand the standard model in remarkably clear and accessible terms, complete with diagrams:
General Outreach: Columns on Mathematics
Cornell Professor Steve Strogatz's wrote a series of columns for the New York Times introducing readers to basic mathematical principals by working through simple examples using relatable terms.
General Outreach: Science in the News Flash
The Harvard GSAS student group Science in the News operates a semi-weekly online journal called SITN Flash which accepts brief submissions from graduate students. As an example, see the 2012 piece by Sarah Rugheimer. SITN members will provide peer editing on all submissions.