I envisage a sixteen-character display on a five by seven dot matrix stretching across the visible surface of the Moon and distorted in order to appear rectangular from Earth, i.e. the pixels towards the limb are stretched and not truly rectangular. It's completely solar-powered and displays black pixels in sunlight but luminous pixels in the dark, so they swap over at the terminator and remain visible. Each pixel is an array of squares black on one side and white on the other which can be flipped over by a series of axles, the whole lot being controlled by a computer and atomic clock. The black pixels are photovoltaic and absorb energy from the sun to generate the required electricity for the display.
Sixteen digits in the following format:
First five: year as in Long Now, with a leading zero so it can be used for tens of millenia and reminds us all to think long term. Gregorian calendar, so there's a Christian bias there unfortunately.
Next seven: HH:MMSS in UT, twenty-four hour clock.
The colon flashes on and off once a second. Time is actually about a second slow to allow for the lag taken for light to reach us and
Total length of display: five thousand four hundred and sixty miles. Each digit is separated by a single pixel, so the pixel directly above us would be about fifty-seven kilometres on a side.
Adjustments to UTC can be made by radio signals.
The display could also be used for scrolling announcements, such as "LOOK BEHIND YOU", "THE DALEKS ARE COMING", "TIME TO COMET IMPACT: XX SECONDS", "EBOLA PANDEMIC IN PROGRESS" or "HI THERE JESUS". No commercial messages though.
Other than these messages, the display would mean you wouldn't need a watch, a calendar or a town hall clock, and it would be easier to make appointments on time, and harder to make excuses. Also, the project could be international and act as a unifying factor for the human race and cause the understanding of current numbering, dating and calendar systems to persist, meaning that there could then be a persistently meaningful message on nuclear waste dumps.
Unfortunately, there's clearly a cultural bias, but it's better than nothing surely.-- nineteenthly, Jul 27 2008 A satellite carefully placed in the appropriate orbit could do the same thing and be much much smaller. Some loss of resolution to be expected.-- WcW, Jul 27 2008 Apollo 11 ... :53-- 2 fries shy of a happy meal, Jul 27 2008 Nothing like a giant c!ock with the wrong time.-- WcW, Jul 27 2008 The colon flashes on and off once a second.-- baconbrain, Jul 27 2008 If it develops a fault, it's an incentive to have colonies on the Moon so it can be repaired. That wouldn't be practical after the collapse of civilisation of course.-- nineteenthly, Jul 27 2008 No thank you. [-]-- imaginality, Jul 27 2008 // The colon flashes on and off once a second //
That will teach you not to order the extra hot Vindaloo with Chilli Garnish .........-- 8th of 7, Jul 27 2008 Well, that would be a luminous lumen, wouldn't it? Maybe arranged with bendy fluorescent tubes.-- nineteenthly, Jul 27 2008 Okay, but I bags it is set to Greenwich Mean Time. People in other timezones can learn to add or subtract to get their parochial time.
That'd probably put paid to the random factor which is BST too. Bonus!-- Loris, Jul 27 2008 Yes, it would tell the same time as GMT, which is what UT practically is. Also, note that it wouldn't be MM/DD/YYYYY but YYYYY/MM/DD, which whereas it's not the Commonwealth (British?) format, isn't as illogical as putting the month at either end.-- nineteenthly, Jul 27 2008 //No commercial messages though.//
Haha. If this ever got baked, I give it five years, tops, before this condition gets broken.
//Other than these messages, the display would mean you wouldn't need a watch//
There are still some of us who prefer not to wear watches, and who'd prefer to look at the moon without a blinking annoying digital clock on it, pun intended.
Also, I approve of the YYYYY/MM/DD format, but surely YYYYYMMDDHH:MMSS is 15 digits or 16 with colon, not 12? Or are you not displaying the month and day?-- imaginality, Jul 27 2008 // The colon flashes on and off once a second //
Eh, so this is a plan to colonize the moon then?
// my favourite date format, that - yyyymmdd //
Useful when you need to reorder your moons chronologically.-- tatterdemalion, Jul 27 2008 //harder to make excuses// except when the moon is on the other side of The Earth.-- Ling, Jul 28 2008 We should also consider the point that it's a bad idea to let lunatics control our lives.-- imaginality, Jul 28 2008 well there goes my platform-- 2 fries shy of a happy meal, Jul 28 2008 Yes, sorry, there should be sixteen characters rather than twelve. For some reason i started with that then had a brianstwam and changed it to the wrong version.
Another thing about that format is that it makes it easier to design the circuitry, as clearly there's not much space on the Moon compared to here, where we've got the Albert Hall, in which to put the single steam-powered difference engine we have in the Empire.
It is a really logical format, i agree, [Ian], in that it goes from largest to smallest, just as the universal format for time of day does. However, i want a leading zero as well.
I don't wear a watch either. Many people don't nowadays, due to them portable blowers.-- nineteenthly, Jul 28 2008 <Imagines the cockroach civilization of "AD 11265", solving the longitude problem with relative ease.> [+]-- 4whom, Jul 28 2008 I also envisage post-disaster doctors having moonlight consultations for to take pulses by the subtle pulsations of lunar illumination.-- nineteenthly, Jul 28 2008 The moon is just over a light-second away, so the clock wil have to be set a second fast for the time to be accurate on the Earth. Time also travels more slowly for us on Earth than it does on the moon because we're subject to a stronger gravitational field (Theory of Relativity).-- hippo, Jul 31 2008 Wouldn't the dot matrix display melt the cheese?-- skinflaps, Jul 31 2008 //If it develops a fault, it's an incentive to have colonies on the Moon so it can be repaired. That wouldn't be practical after the collapse of civilisation of course.//And after the inevitable lunar power outage, the clock would blink incessantly with all zeros, driving the surviving remnants of humanity mad. "The blinking clock!" they would screech, before attacking their neighbors with rocks and titanium golf clubs.-- ldischler, Jul 31 2008 I'm glad to see everyone has been sensible enough not to post "Giant 'Snooze' button on top of the Moon"-- hippo, Jul 31 2008 [Ian], that's weird, i actually heard that Vangelis album for the first time only yesterday.
[Hippo], indeed so and i mentioned that in the idea, though i did ignore relativity.
Maybe the blinking display would actually _cause_ the collapse of civilisation.-- nineteenthly, Jul 31 2008 Pointless for us in the UK - too many clouds. Reminds me of when my Aussie nephews first came to Britain - "Mummy, where's the sun gone?"-- PeterSilly, Aug 01 2008 It does sometimes get very clear in midwinter, just so it can be colder. It could also be remedied by building step ladders several kilometres high. When you wanted to know the time, all you'd have to do would be to don the complimentary breathing equipment and climb the ladder until you were above the clouds.-- nineteenthly, Aug 01 2008 random, halfbakery