This February is a little longer than usual. It's a leap year, and today — Thursday, Feb. 29 — is Leap Day. The calendar oddity means this year is actually 366 days long, instead of the regular 365.

“We know a calendar year as having 365 days; however, in reality the Earth rotates around the sun in roughly 365.24 days,” Khan said. “That .24 is essentially just shy of a fourth of a day; but as ...