Because no human have been there.

[mapuc]

Found this interesting article in Ifl.com

Presenting their work in a Keynote Lecture at the Goldschmidt Geochemistry Congress in Barcelona, Dr Stephanie Olson of the University of Chicago explains how their team modeled likely conditions on different types of exoplanets using NASA-developed computer software to simulate the habitats that could theoretically exist on exoplanets.

https://www.iflscience.com/space/the...earch-suggets/

Markus