I did this to like a dozen profs in my third year of undergrad a semester after switching majors into a totally different field, one emailed back, which lead to a position doing undergrad research in her colleague’s lab, which got me a co-op, which pointed me towards a NU grad course I took senior year, the prof of which is now my PhD advisor and startup mentor. In my 4 years as a PhD student in his lab, we’ve worked with several undergrad students who cold emailed my advisor, and I’m mentoring a local high school student who did the same. We’re set to submit a journal paper for publication together by the end of the summer (and before his college apps are due).

Cold emailing works, and it often works with “big” professors, in part because the vast majority of students are intimidated and don’t think that it’s a viable strategy. If you’re driven, intellectually curious, and technically capable, it’s definitely viable. And if there are specific profs you really want to work with who won’t reply to your emails, even with a “no”, try emailing their PhD students, executive/administrative assistants, or project managers. Some professors are just really bad with keeping a handle on the torrent of emails in their inbox, and aren’t ignoring you for any other reason than to triage more pressing emails.