The Big Dipper wasn't "discovered" in the sense of being newly found. It's been a recognizable pattern in the night sky for as long as humans have looked up at the stars.

Here's why:

* Ancient Recognition: The Big Dipper (also known as Ursa Major, the Great Bear) is one of the most prominent constellations in the Northern Hemisphere. It's been recognized and named by cultures across the world for thousands of years.

* Historical Records: We have evidence of the Big Dipper's recognition from ancient civilizations like the Egyptians, Greeks, and Chinese.

* Not a "Discovery" but a "Recognition": Constellations are simply patterns of stars that humans have connected and given names to. The stars themselves existed long before humans observed them.

So, while we can't pinpoint a specific "discovery" date, the Big Dipper has been a part of human understanding of the night sky for a very long time!