Here’s a cool subreddit where people ask STEM-related questions like:

“If you fired a handgun from the ISS, pointing away from Earth, would it be able to escape Earth’s gravitational pull?”

“What is the advantage of having five, rather than four or six, fingers?”

“How is information encoded between the eye and the brain?”

…some questions on this board are pretty easily answered, but others provoke long, interesting discussions! Usually these questions are answered by people who have some professional knowledge of the topic on which they’re commenting.