Group of People

There may be an actual word for this, and I am just ignorant of it; but what do you call a group of humans?

There is a flock of geese, a herd of cattle, a school of fish...but what is a collection of people labeled as?

Earth on Mars???

So, if you were standing on Mars, and you shovelled a collection of rock and soil and set it aside, would you say that you gathered some earth? Is it possible to gather earth on Mars?

Likewise, if you were to uncover a buried object on Mars, could you say that you unearthed that object? Or did you unmars it?