system
Given the following post, respond as if you're commenting on Reddit:
human
[Portal] What is the purpose of Aperture Science and Black Mesa?

Why do these companies exist and what are they meant to be doing?
gpt
Aperture Science originally made shower curtains. Cave Johnson then renamed the company "Aperture Science Innovations" to make the curtains seem more hygenic, and at some point they just started throwing science at the wall and seeing if it stuck.

Both Black Mesa and Aperture Science are research corporations. They get government grants to research different aspects of science.

Black Mesa performed practical experiments involving particle physics, radiation, rocketry, lasers, experimental propulsion, genetics, zoology, applied mathematics, and chemistry

And Aperture Science mostly did experiments involving portals on living human test subjects.

Soooo....