The Official Handbook of the Marvel Universe states that the character Nova maintains speeds which can be considered "modest", especially when carrying a passenger. The Handbook also concedes that a solid object moving in the Earth’s atmosphere at several times the speed of sound or faster would wreak havoc on the planet and that moving at such speeds would prohibit Northstar from breathing, while the generated wind/friction would ravage his body. On the other hand, the Handbook states that the character Quicksilver was born with adaptations that make higher speeds possible, such as enhanced cardiovascular, respiratory, musculature, and digestive systems, a more efficient metabolism, better lubricated joints, tendons with the tensile strength of spring steel, unidentified bone composition that can withstand the dynamic shock of his touching the ground at speeds over 100 miles an hour, and a brain that can process information fast enough for him to react to his surroundings at high speed.[1]