If a day became 6 hours long, how many seconds would it take for a beach sunset to sink? This is a thought experiment where only Earth’s rotation speed is multiplied by four, while the orbit around the sun, axial tilt, and atmosphere remain as they are now. The location is an equatorial beach on the equinox. Today’s sun moves across the sky at 15 degrees per hour, or 0.25 degrees per minute. Since the sun’s apparent width is about 0.5 degrees, it takes about two minutes to set. If a day is 6 hours, the sky’s rotation speed becomes four times faster at about 1 degree per minute, and the calculation shows the sunset finishes in about 30 seconds. The twilight after sunset (civil twilight) also shrinks from about 24 minutes to about 6 minutes. Up to this point, the numbers can be derived by dividing angles. How clouds, weather, and biological clocks will behave cannot be determined by this assumption alone.
Content type: Hypothetical (scientific thought experiment). This is not a prediction of reality. The visuals are explanatory reconstructions built in Minecraft and are not records of experiments or simulations. The numbers are simple calculations based on reference data, and do not include the bending of light by the atmosphere or changes in the Earth’s shape.
In the series “What-If Worlds: How Far Can One Assumption Be Expected?”, we explore how the world changes from a single assumption, enjoying the mechanics of reality and the limits of expectation.