programming a search engine

I have a question.

Is there a way to program a full-scale search engine completely in PHP/MySQL?

I mean check out IceRocket.com. Do you guys think that engine is done in PHP and MySQL? How does the crawling work?

The reason I chose that site is because it provides a decent set of results, but not as much as Google.

It is possible, yeah, but more powerful search engines may work with a different language, or a combination of many. But yeah, PHP and MYSQL can be used, but you need several smart developers who can write complex algorithms in order to produce an effective search engine.