Today is Star Trek's 50th anniversary, marking half a century since the show first aired on September 8th 1966. Here at Engadget, we're celebrating with an ancient Trekkie tradition: Nitpicking. Today, Facebook announced that it's temporarily replacing its "Like" buttons with a set of Trek-inspired reactions -- a laughing Captain Kirk, a sad, crying Geordi Laforge and an adorably angry Klingon. They're all perfect ...except for Spock. Facebook chose Star Trek's most emotionless character to represent its most emotive reaction: "Wow."