But the advice is mixed for summer flights. âI would suggest buying your airfares for summer as soon as you can,â said Krista Pappas, global travel industry director for Bing, citing high fuel prices, tight seating capacity and strong consumer demand as a recipe for rising rates.
A sidereal period is also defined as the position of an object with respect to the stars. The synodic month is a bit longer than the sidereal month. When a synodic month lasts 29 days, 12 hours, and 44 minutes, a sidereal month lasts 27 days, 7 hours, and 43 minutes.
29.53 days. That's its synodic period, which is the amount of time it takes to go through its phases. This is by far the most commonly used figure. It has a 27.32 day sidereal revolution around the earth, with respect to the stars. The reason for the difference is because the earth orbits the sun. So the moon has to go farther around in order to complete it's entire phase cycle. There is NO relevant orbit which is 28 days. The closest to that is an anomalistic month, which is 27.55 days, and is essentially never used for anything. It's the amount of time between perigees.