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The innermost D ring of Saturn.

Credit: NASA, JPL-Caltech, Space Science Institute

Happy leap day!!!

Leap Day…Why Does It Exist?

Once every four years, an extra calendar day is added: a leap day. But why?

The reason for adding leap days to the calendar is to align the calendar year with the actual year – which is defined by the time it takes Earth to circle the sun. It is equal to 365 days, 5 hours, 48 minutes and 46 seconds, or 365.24219 days.

If all calendar years contained exactly 365 days, they would drift from the actual year by about 1 day every 4 years. Eventually, July would occur during the northern hemisphere winter! Wouldn’t that be weird?

To correct (approximately), we add 1 day every 4 years…resulting in a leap year.

By making most years 365 days but every fourth year 366 days, the calendar year and the actual year remain more nearly in step.

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A viewing favorite

Amazing!

Astronomy compels the soul to look upward, and leads us from this world to another

Plato (via back-to-the-stars-again)

The Galilean moons. From left to right, in order of increasing distance from Jupiter: Io, Europa, Ganymede, Callisto.

A stunning high res photo of Saturn’s Moon Enceladus

Hubbles Jupiter and the Amazing Shrinking Great Red Spot

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