This post is just for fun, although it does plug into the Science of Over the Edge features which appear here every so often. What does it look like when a missile is launched? Well, here's a photo:
Awesomely Weird Expanding Halo of Light Seen from Hawaii This picture is a still taken from a video by Kanoa Withington. It shows the beginnings of an expanding halo--watch the video on the blog link posted above--probably created by a missile launching into space from California. Check out the blog post.
This next photo is also from the same blog, but you may have seen it awhile back, the weird spiral over Norway. Here's a still image of that:
Google "weird spirals over Norway" for more videos.
Here are some more links from Discover magazine online about werid sightings:
Great Balls of Fire Over Australia
So what would it look like if earth had a sure-enough space port where real spaceships going places distant and amazing launched? Maybe very much like these images--well, except for the out-of-control rocket, hopefully a person wouldn't see many of those.