Science encompass the farthest reaches of space and the ground beneath your feet, the future, the past, and everything you’ve seen or experienced. There’s so much to learn about different science topics, and dozens of free online courses to help you expand your mind in whatever directions you want.

These 10 amazing online courses offer free versions and fun learning. While some courses require login to access video materials and interactive course tests, others send summaries on your choice topics straight to your email every day. But wherever you go to get more knowledge, you’ll never run out of things to know.