This answer explores what we can learn from alien starships in orbit around Earth. But what if the aliens went a step further: They send a shuttle down. Humanity dispatched interceptor aircraft, but they were shot down easily. The shuttle landed in a major city, and alien ground troops started to search buildings, killing everyone who was stupid enough to resist. Then, they took off again. They did not take anything or anyone.
My questions are:
- What can we learn about the aliens from this encounter?
- How can we prepare for a second attack?