Today's astro textbook adventures.

[chesuto]

Physicists can make antimatter, in the form of individual particles, and even atoms of antihydrogen (an antielectron in an orbital around an antiproton). Perhaps some pocket of the universe contains antistars made from antihydrogen, with circling antiplanets and anticivilizations of antipeople. If so, you could safely introduce yourself to them over a radio transmission, but we wouldn't recommend a handshake.

then later...

Thus, the gold in your jewelry was forged not in the fires of Mordor, but in a type II supernova whose brightness rivaled a hundred billion stars combined.