The 7¹¹ convenience store the Planet Express crew uses is open 28 hours a day. Why are there 28 hours in a 31st century New New York day?
The Futurama Earth has suffered a number of indignities including having its rotation reversed (That Darn Katz!), moved further from the sun (Crimes of the Hot) and two additional Big Bangs (The Late Phillip J. Fry).
In Crimes of the Hot - As Earth is unable to counter its rising temperature through the usual method (the dropping of a giant ice cube into the ocean), Head-in-a-Jar Gore leads an emergency conference in Kyoto, Japan, where Professor Farnsworth claims responsibility for the crisis.
It seems love detoured him from observing proper emission standards on his prototype robot, and that could necessitate the destruction of all its "descendants." That includes Bender, who resigns himself to having a farewell blowout before being blown up.
At a shindig being thrown to celebrate the saving of the Earth, by blowing up ALL ROBOTS, Farnsworth reveals an idea he believes can save the robots and the Earth. Thanks to the robots venting their excess "gas" the Earth was pushed a bit back from the Sun and slowed down a bit in rotation. This extends the day and adds an additional week to the year, which Head-in-a-Jar Nixon, declares, Robot Party Week.
I don't think too much should be read into this, as it's most likely part of a running gag in Futurama you could call "exaggeration jokes". The idea is that the future has many of the things the present has, just augmented or improved in some fashion (i.e. 28 hour convenience stores instead of 24). Here's a list of some others I remember off the top of my head:
- Caffeinated bacon
- Baconated grapefruit
- Admiral Crunch cereal (instead of Captain Crunch)
- Archduke Chocula cereal (instead of Count Chocula)
- Third, third, and third (instead of half and half)
- Madison Cube Garden (instead of Madison Square Garden)
It's a marketing gimmick by 7¹¹.
7¹¹ has introduced this is a marketing gimmick, or the length of an hour in Futurama has been redefined to be shorter.
That Darn Katz! and Crimes of the Hot may have impacted the length of the day, although there's no reason to believe that either episode did so in any significant way, unless the loss of energy in the transfer of rotational momentum was significant.
In any case, assuming episodes are shown to us largely in order, neither event had come to pass prior to the claim of 28 hours per day.
Less any other references to a 28 hour day, it's merely a marketing a gimmick.
It's a result of the law of conservation of angular momentum: The moon, the tides, wind and waves are all drains on the angular momentum of the Earth, and the Earth cannot spin back up (see footnote).
Of course, none of the currently active effects are in any way large enough to spin down the planet by 4 hours per day per one thousand years; which would require a rate of loss of 14 seconds per day per year!
This would also mean that the Earth would have to be significantly further from the Earth: In any other case, the year would have significantly fewer days. (One entire day less per week.)
We know that the Futurama week has 7 days, (Kif Gets Knocked Up A Notch), and that the Futurama year has 12 months. (
Schmebuary (?) is referenced at some point. I confused Futurama with The Simpsons, and Schmebuary with Smarch.)
We also know that the Earth is not significantly further from the sun (Crimes of the Hot). If it were, the Earth would be sufficiently far away from the sun that global warming would be a non-issue from the get-go.
All of this speaks to the sign being a throwaway gag.
Of course, it is possible that they in the Futurama universe operates with a calendar that is out of step with the seasons, meaning that the year has 372 days, and to split with the consequences. (365 + Robot Party Week)
This leads us back to the problem with angular momentum, and how the Earth could slow down sufficiently over the course of a thousand years.
One possible solution to the problem is to posit that early "modern" space travel (in the 2900 hundreds) failed to take into account the loss of angular momentum when launching large vessels, robbing the Earth of its precious rotation far too early.
Of course, that would require the launch of hardware with a weight within an order of magnitude of the weight of the Earth in the course of a couple of centuries, which is clearly impossible.
In fact, I'm moderately certain that it is impossible to slow down Earth sufficiently within the timeframe allowed, using traditional physics.
In other words: It's clearly a gimmick introduced by 7¹¹, and doesn't reflect on the reality of the situation.
In a much simpler solution, they might have just redefined the length of an hour to allow more of them to fit in a day…
"That Darn Katz!" summarizes the fundamental aspects of this beautifully: Earth is subject to the same spinning down as the cat planet, but of course, we're at a very different point in the planetary life cycle.
It may be a slightly obscure reference to a real 28 hour day. I realise it requires a six day week, but with Blernsday that would go up to 7.