Kurzgesagt released a video called What Do Alien Civilizations Look Like?. It's about the Kardeshev scale. Like all Kurzgesagt videos, the animation is amazing, the information is interesting, and I highly recommend you take a look.
The Kardeshev scale is a method used to measure how far a civilization has advanced. It's specifically talking about technological advancement based around the energy consumed by the civilization.
Kardashev defined three levels of civilization:
- Type I: The civilization harnesses all the available energy on their planet
- Type II: The civilization harnesses all the available energy in their planetary system
- Type III: The civilization harnesses all the available energy in their host galaxy
The scale has been extended to include Type 0, Type IV, and more! We are Type 0; we haven't quite mastered our planet yet. I wonder if we'll survive long enough to make or surpass Type I...
Further Reading: Parallel Worlds by Michio Kaku