Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
Outside the bag the box came in.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.

user:
pass:
register,


                                                             

Lunar backdrop orbiting clock

Turn the Moon into a clock
  (+3, -5)
(+3, -5)
  [vote for,
against]

A solar powered geostationary satellite in the form of two massive hands of a working clock. The orbit should be aligned to coincide with that of the moon, so that the hands can be clearly seen against the bright background. It's orbit would be closer to the Earth than that of the Moon as would be dictated by it's mass and the law of gravity.

This would only really be useful when the moon was in one of it's fuller phases, and would only apply to one timezone - which may draw objection from those other countries who are in a different time zone but can still see the clock.

A possible alternative to this would be to actually build a huge clock on the surface of the moon, but this would impose the additional restraints of lunar gravity & the fact that such an act would be tantamount to vandalism.

stupop, Dec 17 2001

The Iron Chicken http://www.clangers...tm#the_iron_chicken
Nothing to be alarmed about here, Rods. [DrBob, Dec 19 2001, last modified Oct 21 2004]

moon theater http://www.halfbake...idea/Moon_20Theater
[mrthingy, Oct 04 2004, last modified Oct 05 2004]

[link]






       Frankly, if I didn't have a way to independently remove the clock from my view when I wanted to, I'd consider the satellite tantamount to vandalism.   

       It's an intriguing idea, though.
beauxeault, Dec 17 2001
  

       I wonder if we could set up a series of satellites with narrow displays with shielding round the sides, so you could have times for multiple time-zones each only visible in that zone (although this wouldn't work for places whose timezone doesn't correspond to their longitude). Then the only problem would be the fact that it would be almost never visible from Britain thanks to our lovely weather.   

       beauxeault: I feel the same about the moon as it is. Night time is meant to be dark, moon goddess!
pottedstu, Dec 17 2001
  

       blissmiss: You're hallucinating again. (Amazing how my invocation of the moon goddess brought you here.)
pottedstu, Dec 17 2001
  

       "If you want to tell the time from heavenly bodies, what the f*** is wrong with the sun?"   

       Nighttime.   

       How about a series of 24(+) satellites each in the shape of a numeral in a stationary (not geosynchronous) orbit? Onboard rockets would allow for DST adjustments.
phoenix, Dec 17 2001
  

       [Steve DeGroof] Seriously -- or at least slightly more seriously -- if the Earth is blocking the sunlight from the Moon, it would be blocking the sunlight from the 'hands'.   

       Maybe reaaaaalllllyyyy big Indigo panels...
phoenix, Dec 19 2001
  

       [PeterSealy] - There is a difference between "turn the moon into a clock" and "use the moon to tell time," whether you want to believe it or not.
AfroAssault, Dec 19 2001
  

       The other slight problem with using the moon as a clock (apart from the 12 hours a day when it's the wrong side of the earth) is the complex calculations required to go from its position to the actual time. Although a computer-equipped moondial could supplement a sundial, and you could combine that with a database of what time all your neighbours normally go to bed.
pottedstu, Dec 19 2001
  

       Is it going to have a big red button on the top so that you can turn the alarm off in the morning?
DrBob, Dec 19 2001
  

       no, everyone has their own personal nuke that they can send out there. Eventually we'll destroy it. Hey that's cool - that's like the One Big Project of the century that st3f reckons every world generation should work towards.
lewisgirl, Dec 19 2001
  

       leave the moon alone, its for lovers not for you lot to tinker with.   

       there's no romance left any more..........   

       the hills are alive with the sound of music!!!!   

       don't throw bouquets at me, !!!!!!   

       she loves you yeah yeah yeah.....................
po, Dec 19 2001
  

       Off-topic, but I believe the moon is currently drifting away from the Earth. We need to move it closer to the earth, so friction with the earth's atmosphere causes it to lose altitude and counteracts this tendency to drift away from the earth. I'm not sure if this is very practical, but it'd be fun to have the earth orbitting just above our heads. Duck!
pottedstu, Dec 19 2001
  

       If you had a huge clock in space, how long would the second hand need to be before it's tip was travelling at the speed of light (assuming it's a Rolex)?
stupop, Dec 19 2001
  

       That's easy enough to work out, [stupop].   

       c = 3e8 m/s
(distance travelled per second by tip) = 2*pi*radius*(1/60)
3*10^8 = 2*pi*radius/60
radius = 3e8/2/pi*60 m
radius = 2.86e9 m (i.e., about 9.6 light-seconds)
  

       Building such a clock would be a huge undertaking. Getting it to move, however, would be an interesting exercise - even if it were just one tenth of the size.
cp, Dec 19 2001
  

       thats about right; cp but there's a comma too many after i.e.
po, Dec 19 2001
  

       No there's not. Just one comma after i.e. (i.e., it looks like this).
cp, Dec 19 2001
  

       Yes, after a few quick calculations I also came up with approximately 3 million kilometres long. Which is too long really to be arsed with.
stupop, Dec 19 2001
  

       The other problem with making a clock by orbiting a set of clock hands between the Earth and Moon is that the clock hands would be in a different orbital plane than the Moon, and would therefore have a different orbital period. This means that your clock hands will only line up with the Moon semi-occasionally.
mwburden, Dec 19 2001
  

       Re the second hand at the speed of light: Earth is about 8 light-seconds from the Sun. So all you'd have to do is to string a cable from the Sun to Mars. Then the trick would be getting Mars to orbit the Sun in 60 seconds.
beauxeault, Dec 19 2001
  

       Rods, see link.
DrBob, Dec 19 2001
  

       [blissmiss] Actually, since the clock would be in a vacuum, the sound that it would make would be something like:
mwburden, Dec 19 2001
  

       Digital Clock display in GMT
thumbwax, Dec 20 2001
  

       [phoenix] The reason the moon goes through phases is that it is a sphere lit from one side by the sun. When it is full (or nearly so) we are observing it from nearly the same direction that the sun is lighting it. When it is half full, we are observing it from a position 90 degrees from the direction that the sun is lighting it, and when there is a new moon we are observing it from a position 180 degrees from the direction that it is lit by the sun.   

       [Steve DeGroof] Even though the Earth won't be blocking light to the clock face (except during an eclipse of the clock), during half the (lunar/clockal) month the face of the clock will be turned away from the sun. Panels like the ones you mentioned (to make the hands themselves reflect light when not silhouetted by the moon) would only work slightly more than half the month (because during the rest of the time the sun would be on the wrong side of the panels for them to reflect light that would be visible from the Earth.)
mwburden, Dec 20 2001
  

       After a little more thought about [Steve DeGroof]'s idea of panels to reflect sunlight, I thought of a new idea.   

       If 24 clocks were put into geostationary orbits, then all of the clocks on the night side of the Earth would be visible (except during clock eclipses, which would be much more frequent than lunar eclipses because the clocks will be closer to the Earth and closer to the Earth's plane of rotation around the sun) because they would be facing the sun whenever the area of the Earth below them was facing away from the sun.   

       This would also make nightime navigation really easy. If you can see more than one of the clocks in the sky, then East is toward clocks that have later times.
mwburden, Dec 20 2001
  

       [mwburden]
a) You're right. Brain fart on my part. b) You stole my 24 clock idea. (but I like my implementation better)
phoenix, Dec 20 2001
  

       [phoenix] I missed your 24 orbiting clocks idea on my first pass. The biggest problem with that is that there is no stable stationary (as you pointed out, not geosynchronous) orbit. It is the motion of the object around its orbit that keeps it from falling into the gravity well (in this case, the Earth).   

       You might be able to do it, but it's gonna take one heck of a lot of rocket fuel to keep the numbers in place!
mwburden, Dec 20 2001
  

       Whap! (new idea strikes Worldgineer in the back of the head based on phoenix's stationary number idea). 12 numbers at the same height as a geosynchronous orbit, but traveling in the direction counter to the rotation of the earth! That's right - each time we go around once we will have passed each number twice - just the way clocks work.
Worldgineer, Feb 13 2003
  

       That's it! Patent! Patent!
galukalock, Feb 13 2003
  

       Why not just a ring of geostationary billboards that change the number they have on them as they orbit?
rapid transit, May 10 2003
  
      
[annotate]
  


 

back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle