How many stargates were on Earth?

Excuse me, but I couldn't help but notice your mention of stargates. Could you elaborate on that? Specifically, I'm curious to know, how many stargates were actually located on Earth? I'm assuming these are some form of advanced technology that allows for interstellar travel, but I'm not familiar with the specifics. Could you provide any more information on their number, function, and perhaps even their origins? It's a fascinating topic, and I'd love to learn more.