BigPicture -- Celebrating National Manufacturing Day and the approval by the Boston Civic Design Committee of the Gensler GE HQ design
which coincidentally this year is also National Frappe Day October 7
So we chose to address the question Could a Jeff Immelt standing on Mars see his logo on the Fort Point Channel in Boston -- simple answer is YES -- anyone can prove it to yourself -- when Mars in visible above the horizon stand on the edge of the Fort Point Chanel and see if it is visible to you -- the sunlit illuminated earth viewed from from Mars will be about the same brightness
Now when you get down into the weeds the question and the answers get more complicated
So we must ask -- what actually does it mean to see the Logo. Is it sufficient to detect photons from it -- then once again the answer is Yes -- a dark adapted eye can recognize somewhere between 1 and 5 photons as a distinct source. Of course Jeff standing on Mars would see all of the side of the earth facing him and he'd have to separate out his photons from the background.
Here seeing things on the earth from Mars has an advantage over seeing things from earth on the Moon or vise versa. Like viewing the moon from Earth, Jeff can look at an earth whose illuminated face is nearly opposite to the face which he's viewing [a New earth]. So all the GE Logo photons have to compete against are the ones from the artificial lights on the dark side of the earth. However, unlike the earth moon system, the two planets are not synchronously locked in terms of orbits [earth 8766.1525 hrs., versus mars 16488.2562 hrs.] and rotations [Mars solar: 24 hours, 39 minutes, and 35 seconds, versus earth solar: 24 hours, 0 minutes, 0.0009423 seconds]*1, [Mars sidereal day: 24 hours, 37 minutes and 22 seconds, versus earth sidereal day: 23 hours, 56 minutes and 4.0916 seconds] -- so if you wait long enough the right part of the earth will be in the dark facing you, and at the closest point in terms of distance
Now it becomes a matter of signal to noise ratio in the area which Jeff is able to resolve -- without a telescope or even binoculars when you look at Mars it looks very close to a point source -- Earth is a few times larger in solid angle -- but you's have to say it still would look like a point source -- so Jeff's eye would combine all earth origin photons into a few rod cells at most. End result --Earth would look the same to a naked eye on Mars with or without the GE Logo
But as I said before - -all is not lost --it's more complicated. An experiment at Columbia in 1941 showed amazing ability to detect a flashing light
*2
So Jeff needs to pulse the sign at the appropriate rate with an apparent surface brightness greater than the average brightness of the night time earth centered on Boston -- or perhaps pick an angle when most of the earth which he is viewing is ocean with Boston on the edge. -- Give him a pair of average binoculars and it would be easy.
Of course he could just put a laser behind a telescope mounted on the logo with enough power in the laser pulse and appropriate compensatory adaptive optics it would be a "piece of cake" -- over time the laser could transmit a bit map of the actual GE Logo
So -- Jeff Go for it -- we're behind you on this 110%
for a popular-science article on vision limits see
http://www.bbc.com/future/story/20150727-what-are-the-limits-of-human-vision
*1 estimated length of Friday's day
*2 source of the quote about the Columbia Experiment
