From what it actually takes for a giant ball of gas to ignite into a true star to the hidden medical hazards astronauts face in zero gravity, the cosmos is full of incredible surprises. 

David Reneke joins Brent for a wild ride through the universe. We explore the physics of nuclear fusion, look at why our nearest stellar neighbor, Alpha Centauri, isn't quite a holiday destination yet, and unpack the sneaky medical condition known as Spaceflight-Associated Neuro-ocular Syndrome (SANS) that threatens astronauts' eyesight.

• What Makes a Star a Star?: Unpacking the heavy mass threshold and extreme pressures required to spark nuclear fusion, and why objects like brown dwarfs remain "failed stars."

• Alpha Centauri & Proxima b: Examining the distance problem, brutal stellar radiation, and why traveling 4.24 light-years keeps interstellar travel firmly in the realm of sci-fi.

• The Hidden Hazard of Space (SANS): How upward fluid shifts in microgravity flatten eyeballs and blur vision, and how space agencies are repurposing portable eye-exam tools built for seniors on Earth to keep astronauts safe.

If you want a mind-expanding journey through space science, make sure you check out David Reneke's Website for all his latest astrophotography and updates.