In this scenario, there are two Earth-sized planets orbiting one same sun, but they are literally as different as day and night. Both have a 48-hour rotation, but:

  • Planet A has a polar winter in which the sun sets for eight hours a day (40/48 sunlight). In the other seasons, the poles get a whole lot brighter.
  • Planet B has a polar summer in which the sun rises for eight hours a day (8/48 sunlight). In the other seasons, the poles get no sunlight at all.

Are there axial tilts where such phenomena can occur, especially on a yearly basis?


closed as unclear what you're asking by AlexP, Measure of despare., Cyn, Vincent, Brythan Jul 6 at 19:16

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  • $\begingroup$ The polar circles are by definition the lowest latitudes where the sun shines (or doesn't shine) for more than one day, at least on one day per year. On Earth, the sun shines for five sixths of a day (in summer, obviously) as far south as St. Petersburg; see white nights; quite obviously, in the same city, in winter the sun shines for one sixth of a day. What exactly is the question? (P.S. Do you want a planet where all the places experience the same duration of light and dark, and not the same amout of light and dark?) $\endgroup$ – AlexP Jul 6 at 10:28
  • $\begingroup$ You are looking for a winter with long days and a summer with long nights. If it is not the day length that makes the season, is it the average temperature? $\endgroup$ – Willk Jul 6 at 12:57
  • $\begingroup$ Your edit really doesn't clarify anything as you seem to describe the two planets in a way that would make them identical. If each planet is in the L3 position of the other planet with the sizes you've described, they'd be unstable and unlikely to persist in this orbit for any length of time, what are you trying to achieve here? (From review) $\endgroup$ – Measure of despare. Jul 7 at 0:20

Elliptical orbit and varying sunlight intensity.

For reference: how it works on Earth. https://en.wikipedia.org/wiki/Axial_tilt

how seasons work

Usually summer is warmer and I think on earth that is a direct function of day length which is longer ins summer; the reverse is true in winter.

The OP wants "summer" that has long nights, with more time for summer dreams, ripped at the seams. OP requests "winter" that has long days. I am going to assume that summer means it is warm and winter means it is cool. We will accomplish this with an elliptical orbit.

https://en.wikipedia.org/wiki/Elliptic_orbit ellipitcal orbit

Don't watch that elliptical orbit gif too close or you will look up and 3 hours will have gone by.


Considered from the perspective of the Arctic: long days coincide with the furthest extent of the orbit. Days are long but the sun is distant so things stay cool: I am calling this winter because it is cool. The reverse happens in "summer". Days are short in the Arctic because it is tipped away from the sun but it is close and so sunlight is stronger.

The reverse would be true in the antarctic: scorching hot summers with long days and freezing winters with long nights.

Other aspects of the OP I consider red herrings. But I worry about that Dailey downvote if those criteria are not included somehow. So: there is another planet exactly like this one in the system. Both of these planets rotate so as to have 48 hour days.


It seems you have gotten winter and summer backwards. Summer is the one with long days, and winter has long nights.

That aside, when a point on the planet has a long day, the opposite point on the planet must have a long night at the same time. If the northern hemisphere has long summer days this month, the southern hemisphere must have long winter nights this month. This is an inescapable consequence of the planet being round: it is always light on one half and dark on one half.

  • $\begingroup$ One has the winter days and one has the summer nights. It's two planets, not one. $\endgroup$ – JohnWDailey Jul 6 at 23:12

48-hour rotation, but one has a polar summer where the sun shines for only eight of those hours

Summer is astronomically defined as the period when the daylight time is longer than darkness. Since on average the daylight should be half of the day, what you state sounds impossible.

  • $\begingroup$ What do you mean, "should"? $\endgroup$ – JohnWDailey Jul 6 at 23:10

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