Google run a global reverse proxy style caching service "Google Global Cache", this is where they provide servers at no charge to ISP's and direct bandwidth hea

Google run a global reverse proxy style caching service "Google Global Cache", this is where they provide servers at no charge to ISP's and direct bandwidth heavy traffic to these machines for the ISP's IP ranges, typically when this first came out they were just hosting the Youtube and local Maps traffic locally. However about a year ago they actually started to service the google.com domain from these machines, therefore that will explain the better ping response, and if you do a WHOIS on the IP range or look at the source ASN you will probably find it's your ISP and not the Google network. Akamai and Netflix offer some very similar services to ISP's if your interested in reading a bit more about it, specifically for Akamai they host a lot of the Facebook images and Apple updates/images traffic from these machines in your ISP network.