What Makes February a Dwarf Month?

[bobie]

Hi,
I hope this is the right forum to ask the following:

January has 31 days, February 28 and March 31 : 90 days in total, is there an astronomical reason why we do not have three 30-day months?

 

[paulcretu]

It has historical roots from the ancient times. The calendar has been reformed several times in order to compensate the moon's period.
I've seen a reply here with the history part:
http://answers.yahoo.com/question/index?qid=20110130164834AAEsSEb

 

[UltrafastPED]

The traditional Roman calendar was based on the lunar year:
http://en.wikipedia.org/wiki/Roman_calendar

When Julius Caesar adopted the solar year, the new calendar became known as the Julian calendar:
http://en.wikipedia.org/wiki/Julian_calendar#Changes_to_the_months

You could write a term paper on all of the details!

 

[bobie]

Thanks, excellent explanations!

 

[tiny-tim]

also, the year used to begin in march …

(which is why eg october used to be the eighth, octo-, month)

so february was the "runt" month that only got what was left over after all the other months had fed

 

[phinds]

also, the year used to begin in march …

(which is why eg october used to be the eighth, octo-, month)

so february was the "runt" month that only got what was left over after all the other months had fed

Cool information. Thanks.

 

[bobie]

So, we might have without any problem:
April through August 31 days and September through March 30 days.

 

[SW VandeCarr]

By February, people were weary of winter. So they shortened February to make spring come sooner. :)

 

[Vic Sandler]

also, the year used to begin in march …

(which is why eg october used to be the eighth, octo-, month)

That doesn't sound right to me, but I could be wrong. I thought that in the pre-Julian calendar, January, the first of ten months, was named after the god Janus who looked both back and forward to the old and new years. September through December were then months 7 through 10. Afterwards the months of July and August, named after Julius and Augustus Caesar were added, shifting those later months and creating the Julian calendar.

 

[tiny-tim]

from http://en.wikipedia.org/wiki/January#History …

Traditionally, the original Roman calendar consisted of 10 months totaling 304 days, winter being considered a month-less period. Around 713 BC, the semi-mythical successor of Romulus, King Numa Pompilius, is supposed to have added the months of January and February, allowing the calendar to equal a standard lunar year (354 days). Although March was originally the first month in the old Roman Calendar, January became the first month of the calendar year under either Numa or the Decemvirs about 450 BC (Roman writers differ).​

 

[Vic Sandler]

I sure got that wrong.

 

[BobG]

That doesn't sound right to me, but I could be wrong. I thought that in the pre-Julian calendar, January, the first of ten months, was named after the god Janus who looked both back and forward to the old and new years. September through December were then months 7 through 10. Afterwards the months of July and August, named after Julius and Augustus Caesar were added, shifting those later months and creating the Julian calendar.

I sure got that wrong.

Part right.

July and August weren't just added to the calendar. Existing months (Quintillus and Sextillus) were renamed in honor of Julius Ceasar and Augustus Ceasar.

 

[BobG]

Hi,
I hope this is the right forum to ask the following:

January has 31 days, February 28 and March 31 : 90 days in total, is there an astronomical reason why we do not have three 30-day months?

March 21 would have to be on the vernal equinox (or close to it once leap years were set up). December 21 would have to be on the winter solstice (or close, given leap years). Doesn't explain why December, January, and February couldn't all have 30 days, but even in the early days, you wanted the equinoxes and solstices to work out right. That means you can't push days across those key points.

But you do have to have more short months going from the Autumnal equinox to the Vernal equinox (the Earth reaches perihelion the first week of January) than you do going from the Vernal equinox to the Autumnal equinox (the Earth reaches apihelion the first week of July).

 

[bobie]

But you do have to have more short months going from the Autumnal equinox .

By how many days is winter shorter than summer?

 

[D H]

By how many days is winter shorter than summer?

About five days -- assuming you live in the Northern Hemisphere. It's the other way around if you live in the Southern Hemisphere.

 

[BobG]

By how many days is winter shorter than summer?

You could figure that out just by counting the 31 day months between Mar 21 and Sep 21 (Mar, May, July, & Aug) and then counting the 31 day months between Sep 21 and Mar 21 (Oct, Dec & Jan) and then subtracting the days that February is short (2).

Summer months: +4
Winter months: +1

Which comes to a difference of about 5 (at least for really large values of 3).

 

[bobie]

So, we might have without any problem:
April through August 31 days and September through March 30 days.

So this solution is viable

 

[D H]

It's March 20 and September 22 (on average), not March 21 and September 21.

 

[Vanadium 50]

February is so short it is now classified as a "dwarf month".

Emboldened by their success in declaring Pluto not a planet, the International Astronomical Union determined this week by a close vote that February is too short to be considered a true month. It has, however, been granted the newly-created status of "dwarf month." It shares this dubious distinction with several other calendar time spans, including Labor Day Weekend, Christmas Vacation, and the Time Between When You Were Supposed to Get Your Oil Changed and When You Actually Did.

"It only seems fair," said IAU President Ron Eckers. "February reaches a peak size of 29 days, averaging only 28 days for 75 percent of the time. Recent research has shown that other periods, such as the Time Between When You Were Supposed to Get Your Oil Changed and When You Actually Did, often exceed this meager time frame. In fact, this erratic behavior only strengthens our case that February does not belong in the same classification as the eleven 'true' months."

Eckers also warned that the crop of 30-day "so-called" months should be careful to maintain their number of days. "They're already cutting it pretty close in my book."

I read it on the internet, so it must be true.