Exoplanets, planets beyond our solar system, whether orbiting other stars or floating freely between them, can make the planets closer to home look tame by comparison. “Hot Jupiters” are star-hugging, infernal worlds. “Super-Earths” are super mysterious. Frozen planets, gas giants that make Jupiter look puny, or small, rocky planets in Earth’s size range but in tight orbits around red dwarf stars – the catalog keeps growing.