Noctilucent clouds — the rarest clouds in the world — glowed like shimmering cobwebs in the sky over the San Francisco Bay Area early Friday morning, and experts think they were likely the result of a rocket launch. Skywatchers across the region were delighted by the otherworldly spectacle overhead and shared images on social media. One Twitter user posted a photo taken in the Sunset District at 6:30 a.m. "Pretty crazy looking," the tweet read. Scientists chimed in with excitement. "Great shot of what appears to be a noctilucent cloud over the SF Bay Area this morning!" UCLA climate scientist...