Some stars in the universe grow to 300 times larger our own sun. But how do they get so big, and how do they sustain their mass?
Neil Armstrong almost made a mistake. He had found an interesting rock sticking out of a formation. Curious to see what the rock was made of, he needed to examine its interior more closely. So he reached for his hammer and took a swing. The rock was far more brittle than he anticipated, and instead of cleaving in two it shattered. One of those shards flew away with so much force that it left behind a bloody gash in this forearm.

