Though the old serif logo had a "scholarly" feel which correlates with the purpose of a search engine. That said, I think the new sans serif logo is much better because it is more modern/forward looking which better encompasses Google's wide breadth (maps, chrome, mail, docs, etc).
This is the Norse protection symbol called Vegvísir, which has a deep meaning. The Icelandic word literally means ‘guidepost’ or ‘direction sign’. In modern popular culture the Vegvísir is often called Runic Compass or See the Way. It is often associated with the Viking Age, which is not correct: this symbol is from the 17th century Icelandic grimoire called Galdrabók (‘magic book’). Vegvísir was drawn on one’s forehead with blood to prevent a person from getting lost.