Astronauts who’ve lived on the International Space Station and “walked” in space tell all: what it’s like to ride on a space ship, and to eat, sleep, exercise, and even do science—in space.

Leading researchers in the arena of human enhancement are turning-back the clock by reopening “critical windows” for cognitive and physical development that until recently seemed to permanently close after childhood. Brian …

What happens when a black hole a billion times more massive than our sun powers a star-like object? It’s a quasar of a question. These massive and extremely remote celestial …

For all that Darwin contributed to our understanding of the biological world, he was haunted by one vexing question: How does the incremental process of evolution suddenly produce, say, humans—animals who walk upright, communicate through language, and possess the brainpower to travel to the moon?

What is color? It seems like a simple question at first, but when you think about it, the reality of what we’re seeing is a pretty complex situation. Our human eyes sift through a small piece of the vast electromagnetic spectrum and translate it into every color of the rainbow.

What’s the most complex structure in the known universe? Hint: You’re using it right now to answer to this question. While you keep brainstorming, let’s discuss your cerebral cortex. This …