With the popularity of social networking services, big social data analytics emerged in various applications, such as discovering trending topics, monitoring public sentiment, and identifying human mobility patterns. In this paper, we take the opportunity of The 2017 Great American Eclipse, a once-in-a-lifetime event, to look into its potential social, emotional, and human movement impacts at the national level. Specifically, we collected more than five million English eclipse- mentioning tweets in a real-time manner using Twitter Streaming APIs. Then we profiled spatio- temporal distributions of the data, extracted both hashtagged and latent topics, analyzed emotions using polarized words, emojis and emoticons, and revealed both interstate and intrastate eclipse- chasing travel patterns. Our study provides a comprehensive example of understanding big social data and its associated influence from diverse perspectives.