Leap years prevent 'calendar climate change'

Mar 01, 2012

Without leap years, Earth would experience "calendar climate change" and the seasons would completely swap every 750 years, a Queensland University of Technology scientist says.

Astronomy expert Dr Stephen Hughes said leap years kept the calendar in , otherwise the middle of summer would become the middle of winter - as once happened in .

"The year, defined as when the sun arrives back at the same place in the sky on its apparent circuit around the Earth, is not exactly 365 days long," Dr Hughes said.

"Rather, it's 365 days, 5 hours and 48 minutes. In other words, the calendar is out of sync by about one day out every four years.

"So, every four years an extra day puts the Earth calendar in sync."

Dr Hughes, from QUT's and Engineering Faculty, said the additional day in February still did not perfectly compensate for extra time.

"Because the extra time required for the sun to get back to the same position is just short of one quarter of a day, three leap days are missed out every 400 years," he said.

"Years divisible by 100, such as 1900 or 2100, are not leap years. Years divisible by 400, for example, 2000, are leap years.

"If there were no leap years, the seasons would completely swap every 750 years - i.e. the middle of summer would become the middle of winter - calendar .

"This actually happened in ancient Egypt.

"The Egyptian calendar year was exactly 365 days in length. In the Sinai Peninsula there is a carving by an Egyptian worker complaining that it has become summer in winter."

Explore further: Experts express concern over cyclone trends in the British-Irish Isles

Related Stories

Earth's orbit creates more than a leap year

Feb 08, 2008

The Earth's orbital behaviors are responsible for more than just presenting us with a leap year every four years. According to Michael E. Wysession, Ph.D., associate professor of earth and planetary sciences ...

Extra tick restarts time, tech debate

Dec 26, 2005

Time marches on and so does the debate over whether a "leap second" does any good in helping Earth catch up with the world's atomic clocks.

Countries consider time out on the 'leap second'

Jan 17, 2012

It's high noon for the humble leap second. After ten years of talks, governments are headed for a showdown vote this week on an issue that pits technological precision against nature's whims.

Recommended for you

Volcanic eruptions slow down climate change - temporarily

7 minutes ago

Although global concentration of greenhouse gases in the atmosphere has continuously increased over the past decade, the mean global surface temperature has not followed the same path. A team of international ...

Image: The North Sea abloom

2 hours ago

Despite its cold waters and harsh winds, the North Sea is a fertile basin for phytoplankton blooms. The drifting, plantlike organisms tend to be most abundant in late spring and early summer due to high levels ...

Warm winters, summer rain help wildfire recovery

3 hours ago

Using more than a decade's worth of daily satellite images, researchers have determined ecosystems of South Africa's Cape Floristic Region bounce back from wildfires much more quickly in warmer winter weather.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

RobertKarlStonjek
1 / 5 (1) Mar 01, 2012
for the sun to get back to the same position

The Copernican revolution has reached all quarters just yet ~ for some, the sun still orbits the Earth :)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.