The same guys that planted those false Trilobites, will be out there manufacturing artifacts for sure. It is a conspiracy to trick us into believing in strange and diverse life formation, marveling at the richness of the universe, so we don't find the time to look into the business of those sneaky bureaucrats putting more wheels into the machinery. No expense is spared in the quest to bog down our lives!
P.S.
Now for the mandatory statement:
Should you see any aliens, kill them first, and then terraform their habitat. Artifacts should be shipped to your local authorities if Imperial, and if not Imperial, please hit the self destruct button, in order to avoid contamination. Have a nice and productive day!