Science & Technology UNC professor can explain reason for leap years
| UNC professor can explain reason for leap years |
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| Tuesday, February 26, 2008 | |
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Charles R. Evans, Ph.D, a professor of physics and astronomy at the University of North Carolina at Chapel Hill, is available for interviews on why February will be a day longer this year, for leap year. Evans specializes in general relativity and theoretical astrophysics. Every four years, Feb. 29 is added to the calendar to make up for a quirk in Earth’s orbit and rotation, Evans said. “The Earth spins on its axis and that gives us the day,” Evans said. “The Earth also orbits around the sun, and that gives us the year. But those two are not exactly divisible by one another. The catch is that in the time it takes for the Earth to go around in its orbit, Earth spins on its axis 365 and a quarter times – if you let about four years go by, then you will have accumulated an extra day. “If your calendar never took into account that fraction of a day that happens each year, the seasons would migrate around the calendar. If you simply define your calendar as having 365 days, in about 500 years summer would occur in September” Note: Evans can be reached at (919) 962-2171 and This e-mail address is being protected from spam bots, you need JavaScript enabled to view it News Services contact: LJ Toler, (919) (919) 962-2091 |