Comments on: Q: “Once in a blue moon” is a rare event. But what does “blue moon” really mean?

By: Debby

Debby — Wed, 09 Jun 2010 01:50:49 +0000

for(int i=1890; i<1910; i++)
{
NSDateFormatter *df = [[[NSDateFormatter alloc] init] autorelease];
[df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSString *s = [NSString stringWithFormat:@"%02d-02-01 01:00:00", i];;
NSDate *aDate = [df dateFromString:s];
NSLog(@"s=(%@) dateFromString=(%@)", s, aDate);

// Why do some dates around the beginning of the 19th century show a GMT hour-offset of HUNDREDS of hours????
// 1902-02-01 01:00:00 -053211
}

By: elvis kovacic

elvis kovacic — Thu, 20 May 2010 04:24:10 +0000

Cool topic. I never real thought about the moon benig blue but now that I think of it, its blue alot.

By: Twan

Twan — Sun, 21 Feb 2010 19:50:06 +0000

To bad, you didn’t include the maya calendars (http://en.wikipedia.org/wiki/Maya_calendar) because these are the only ones in sync with the moon / nature

By: Alex Hilton

Alex Hilton — Sun, 10 Jan 2010 21:23:06 +0000

Matt,

You’re talking about an average slowing over billions of years being counteracted by a temporary speeding up.

Bit like having a couple of cold years in an otherwise above temperature decade not making a difference to a general warming trend

By: Kevin

Kevin — Tue, 05 Jan 2010 22:42:57 +0000

Best thing I read today. Thanks.

By: Bruce

Bruce — Tue, 05 Jan 2010 22:13:28 +0000

What an excellent, fascinating post — thank you.

By: Daphne

Daphne — Sun, 03 Jan 2010 12:13:37 +0000

Maybe we should stop focussing on moons and calendars and think about cooking: French “bleu” means rare and is translated “blue” in American cookery. If we can understand why raw steak is called rare in English and bleu (blue) in French we may understand why something which happens less often than at least once a year; whether the 13th lunar month, the third full moon in a season of four, or two full moons in the same month – is called rare/bleu/blue.

By: matt

matt — Thu, 31 Dec 2009 00:02:17 +0000

How can the Earth’s rotation be speeding up AND slowing down simultaneously?

“Surprisingly, while just about every year between 1972 and 1999 required a leap second to keep the clock synchronized with the Earth’s rotation, there have only been two leap seconds added in the last ten years. The Earth has sped up just a bit, and no one knows why.”

“…the Earth’s rotation is also slowing down and will eventually match the orbit of the moon.”

By: Shawn Dehkhodaei

Shawn Dehkhodaei — Tue, 29 Dec 2009 08:23:44 +0000

Very interesting read, and I like the depth of information provided (and the commentary). I’m Persian (Iranian) so I just wanted to add that in the Persian Calendar (Jalali Calendar), the length of a year, is actually measured astronomically, meaning that our “calendar year” is not always 365.2425 or some fixed number; it changes slightly every year. To explain it a bit better, our “new year” count down is at a different time of the day, each year, meaning that the actual orbit of the Earth is measured down to the millisecond.

Another thing to note is that the Persian Calendar is completely synced to the movement of the Sun, and to the seasonal equinoxes (Spring, Summer, Fall, Winter). The first day of the calendar, is the Spring Equinox (March 21st). We also have a celebration on the Winter Equinox, where we observe the “longest” night of the year (generally December 21st). I’m always amused by the myriad of calendars out there, but I always find that the Persian Calendar seems quite accurate (my bias perhaps).

I found some interesting details on it here: http://en.wikipedia.org/wiki/Iranian_calendar
in case anyone is interested.

What I find really odd is the Islamic Calendar (I’m Muslim by birth but that’s about the length of my involvement). In most Arab countries, they do NOT have a Solar calendar to keep things sane. For example, when I was working in the UAE, they used the Islamic Calendar, for everything, but they also used the Gregorian calendar to celebrate the “New Year” ??!! There is also a joke that an Arab never knows how old he/she really is because of the rotating [lunar] calendar. Or as you put it, they’re getting older at pace of 3% faster than the rest of us !!! I’m not racist, and this remark is not meant to be racist; but this is a serious problem.

By: Uncle Al

Uncle Al — Thu, 24 Dec 2009 23:54:38 +0000

ignores not just all of chemistry, where everything happens in even ratios Isomorphous substitution allows atoms of similar size and the same valence to (randomly) fit in the holes. Purifying lanthanides is a nasty example. Geologly is filthy with it, especially if substitution can be made two or more atoms at a time to balance charge. We have rocks and alloys with composition ranges.

Organic chemistry compositionally behaves (until polymers, capped nanoparticles, colloids arrive). Some fun there is building molecules with no static structure, like bullvalene (somebody didn’t believe until it was synthesized). Inorganic gives us IF7. Silyl enol ethers of 1,3-diketones, etc. The universe is a messy place. All the fun is in the footnotes