New moon western horizon shortly after sunset and before moonset. A lunation or synodic month is the average time from one new moon to the next. In the J2000.0 epoch, the average length of a lunation is 29.530588 days (or 29 days, 12 hours, 44 minutes, and 2.8 seconds). However, the length of any one synodic month can vary from 29.26 to 29.80 days due to the perturbing effects of the Sun's gravity on the Moon's eccentric orbit. In a lunar calendar, each month corresponds to a lunation. Each lunar cycle can be assigned a unique lunation number to identify it. The
Iditarod Trail Sled Dog Race Seavey with a time of 8 days, 11 hours, 20 minutes, and 16 seconds. As of 2012, Dallas Seavey was also the youngest musher to win the race at the age of 25. In 2017, at the age of 57, Dallas's father, Mitch Seavey, is the oldest and fastest person ever to win the race, crossing the line in Nome in 8 days, 3 hours, 40 minutes and 13 seconds. Dallas finished second, two hours and 44 minutes behind. Teams generally race through blizzards causing whiteout conditions, sub-zero temperatures and gale-force winds which can cause the wind chill to reach