Letters

Sun’s speed unclear
Sun’s speed unclear
In “Sun’s shock wave goes missing” (SN: 6/16/12, p. 17), Nadia Drake reports the speed of the sun through space at 83,500 kilometers per hour, or roughly 11,000 km/h slower than previously thought. Yet in the same issue (“At home in the universe,” p. 22), Alexandra Witze reports the speed of the sun relative to galactic rotation as 220 kilometers per second.