I have posted before about stardates and stardate apps for iPhone. A free new app was released in November (55877) named Sternzeit, which is German for "stardate", by Sebastian Bothe. Originally the US AppStore description was in German, although text within the app was in English, but the description has now been translated.

Version 2 was released today (56015), which fixes an issue with not being able to select the year. You can now select dates in any year to convert to a stardate. Initially there was a bug which caused it to revert to the current date every 30 seconds, but it's working now for me.

The unique feature of this app is that it gives you the ability to share the stardate via Twitter, email or SMS, with a default message like, "Captains's log, stardate : -310757.56". You can also follow other users of the app on Twitter via a hash tag from within the app. I appear to be the first tweeter.

The real problem I have is that the algorithm he uses starts counting from the year 2323, which means that all stardates in the current century are negative, as well as being six digits, unlike the ones on TV, which were four or five digits, and lack the minus sign. It's fine if you want to find the stardate Capt. Janeway brought Voyager back to the Alpha Quadrant in the year 2378, but it's not what I want in my tweets. I know that the "algorithm...is known throughout the net", but it was devised specifically for the 24th century, and doesn't even work for Capt. Kirk's time, let alone ours. There are plenty of other stardate algorithms on the Net, like the contemporary date algorithm at TrekGuide.com. (I don't recommend the Andrew Main algorithm, used by Google Calendar.)  IRL astronomers have their own way of dating star observations, which looks a lot like the stardates on The Next Generation, Deep Space Nine and Voyager.  And of course, the latest version of Star Trek simply uses the year number with a decimal.

At least he no longer states that 2323 was the year of the first warp-flight, when every Trekkie knows it was nearly three centuries earlier, in 2063. How did he think Kirk got around in the 2200s?

Sadly, I can't update to the new Sternzeit version on my iPhone 4S because for some reason the app requires the new iOS 5.1, and I am stuck on 5.0.1 because I'm jailbroken. Funny, I've updated scores of other apps this month and none of them require 5.1. I had to try it on my iPad, so of course it looks like crap because it's designed only for iPhone, for some reason.

MJD 56016.339



I have been waiting for electronic books my whole life.  I've always been a big sci-fi fan, and it only made sense to me that e-books would be superior in every way to their paper counterparts.  The very first episode of Star Trek made with Captain Kirk, which first aired the day my little sister was born, showed characters reading e-books and other documents.  Granted, in that particular episode they were reading relatively bulky monitors attached to the wall, rather than what we would call an e-reader or tablet, but in later episodes handheld tablets are used, some of which were touch-sensitive, and others which used a stylus.  The monitors worked with removable cards, referred to as "tapes", although it was not clear whether they contained literal tape inside, and sometimes documents are transferred directly from the ship's computer.  There are plenty of other works of science fiction which also depict e-books.

The first time I saw a dedicated e-book reader in real life was about 20 years ago, when I was on a flight sitting next to a man using a prototype, which he said the company he worked for was developing.  I don't know whatever happened to that particular device, but I know that a number of portable e-book readers have been produced over the years, which did not succeed for various reasons.  E-books themselves, however, could be read on personal computers, and as laptop computers became smaller, they became more convenient for reading e-books, until dedicated reading devices and tablets finally made e-books more convenient than the paper kind.

I always knew that this day would come.  Others were more doubtful.  I don't know how many times over the years that I heard people complain, even now, that e-books could not provide the same experience as paper books, the same texture and smell and the physical action of turning the pages, that reading electronic displays are too tiresome, etc.  Some of these criticisms were merely technological, and could be solved with innovations such as e-ink.  Others were rooted in sentimentality for superfluous features of the old medium, which those who will grow up with e-books will not share.  Do we today miss the characteristics of scrolls and hand-written parchment, or of clay tablets?  No, because most of us today have no experience with those things, and would consider it perverse to prefer them.  Likewise, our descendants will not recognize the desirability of paper books, except perhaps as antique collectibles.

I have always found paper books to be less than optimal.  They tended to be heavy, often heavier than my iPad today.  They were also bound, so that you had to prop them open, lest they close or change pages by themselves, and then you had to worry about damaging the spine.  And once they closed, you would lose your place if you did not have a bookmark.  It was cumbersome to have to flip through hundreds of pages.  E-book haters talk about snuggling in bed with paper books, but I always found them to be poor bedtime companions.  Plus, you cannot read them without a light!

So I am thrilled that the technology has finally caught up with sci-fi.  What I find irritating is that many people confuse the content with the medium.  For many, the word "book" refers strictly to bound leaves of paper.  However, there were books before it was common to write them on codices, and there will be after paper is gone.  A book is the words that are written on the paper, on digital medium, or other media such as parchment, clay or stone, and is independent of the medium, itself.  Remember, Homer did not write on paper; he could not even see!  But you can now download his works as e-books.  Books will live on, longer than paper will.

MJD 56015.026


The equinox marches on

Spring has officially arrived in the Northern Hemisphere.  Not that you'd notice here in the Western US, where it's unseasonably cold.  Of course, in the East it's unseasonably hot, and in the middle the combination is causing tornadoes.

In fact, spring arrived last night, at 10:14:09 pm my time, Pacific Daylight, on the 19th day of March by the Gregorian calendar (56006.21816).  That's the 20th of March for most of the world, but this is still the earliest equinox in over a century.  Part of the reason for this is that there was a leap day last month, which pushes the date back a day.  The next one, in 2013, will come nearly six hours later, and so on until the next leap year in 2016, when it will again jump back a day.  In fact, it will jump back slightly more than a day.  It continue to slip earlier and earlier every leap year, until 2100, when we will skip a leap year.  The reason we have leap years is to keep the equinox from arriving later and later every year.  The reason we skip leap years is to keep the equinox from arriving too early.  The earliest vernal equinox this century will be in 2096 (86686.5848) after which it will advance nearly six hours each year until 2103 (89243.265).  In 2104 the leap year cycle will start again, so the equinox date will again go back a day, or about 18 hours before 2103 (89608.509). 

For the rest of this century, spring will arrive more and more often on the 19the day of March in Pacific Daylight Time, instead of the 20th.  Then it will arrive on the 20th every year from 2099 to 2135.  Of course, it will always arrive earlier in the Eastern Hemisphere, often on the 21st day of March, as it's supposed to.  The Romans, it's said, originally fixed the equinox on the 25th day of March, as Julius Caesar noted on his calendar, but by the fourth century it had slipped to the 21st, and the latter date is the one that Pope Gregory noted on his calendar, by which time it had slipped by between 9 and 10 days, so he dropped 10 days, although it probably would have been more accurate to have dropped only 9, since it usually falls on the 20th in Europe.  At least it's closer in Asia and Australia.  (I know that doesn't quite add up, since the date should have slipped only 3 days in the first four centuries rather than 4, but I don't know the reason for the discrepancy.)

There is a good graph of the March equinox's wanderings on Wolfram.

MJD 56006.974


Astronomers gone bad

Last week astronomer Phil Plait posted on his Bad Astronomy blog an article about leap day. In it he stated:
The year is not exactly 365.25 days long. Our official day is 86,400 seconds long. I won’t go into details on the length of the year itself (you can read a wee bit about it here), but the year we now use is called a Tropical Year and it is 365.242190419 days long. With malice aforethought — my calculator won’t hold that many digits — let’s round it to 365.2421904... There is no official rule for leap days with cycles bigger than 400 years. I think this is extremely ironic, because the amount we are off every 400 years is almost exactly 1/8th of a day! So after 3200 years, we’ve had 8 of those 400 year cycles...This whole 400-year thingy was started in the year 1582 by Pope Gregory XIII. That’s close enough to the year 1600 (which was a leap year!), so in my book, the year 4800 should not be a leap year.
Except that he's wrong.  He was also wrong when he posted this originally four years ago. I posted a correction in the comments then, and I've done so again now, but obviously he does not read the comments. The reason he is wrong is because he's using the wrong value for the year. The document that Gregory issued establishing his calendar is called the Inter gravissimas.  It clearly states that the reform is intended to fix the date of the vernal equinox, upon which Easter is based.  The year defined by equinoxes is not the same as the Tropical Year mentioned above, but a slightly larger value between 365.24237 and 365.24238.  This is closer to the average Gregorian year of 365.2425 days.  Using the equinoctial figure, it will take about 8000 years before it's off by one day, which would be in the tenth millennium.  Due to the variability of the equinoctial year, we cannot even predict its value that far in the future.  The way it's trending now, I could even be much further in the future.

He is not alone.  This error is often repeated by astronomers.  It is sometimes traced back to John Herschel, but during the Revolution French astronomers calculated that the mean year was between 365.2422 and 365.24225 days and proposed an adjustment after 4000 years.  But none of them were using the vernal equinox, as Gregory did. The correct figure may be found in Wikipedia and others.  Anybody can figure it out themselves simply by taking the average between the equinoxes of any two years.

MJD 55994.238