![]() ![]() That is why you can, for most practical purposes, forget about the revolution (which causes the different seasons) and concentrate only on the rotation, at least fo sun raising purposes.Īt first ask yourself the question what do you mean by "East"? It takes a year for Earth to revolve around the Sun, and only one day to rotate about itself. Some posts introduced foreign elements or useless nitpick in order to differentiate themselves, I just gave the basic answer. OP didn't ask about that, he knows the conventional definition and we all know what 'East' means. Why should my post answer that off-topic and silly question? Incnis, you ask a new question about that and I will address it.Īny definition is a convention, you can debate for hours which is the best for Venus. The answer ignores the problem “how west–east direction is defined”? - Incnis mrsi It does not address the question in any meaningful way. If the Earth spinned in the opposite direction the Sun would appear to rise from the West. The revolution affects the difference between sidereal time and solar time, and makes the solar day $\approx 4$ minutes longer You say that Sun rises in the East (with a certain degree of oscillations due to the tilt of the axis) just because the Earth spins from West to East. The Sun does not rise, it is the horizon that goes down. This is captured in the "equation of time" and shown, for example, in this graph (from ):Īnd just for your amusement - on October 25th, the sun briefly rises in the South on Svalbard (Spitsbergen) before disappearing for the winter. This is enough to make a sundial "off" by up to 15 minutes, depending on the time of year. ![]() ![]() But the year is 365.24 days, and while that is so, the sun will rise "mostly in the east".Ī small addendum: because the earth's orbit is elliptical, its angular speed relative to the sun changes a little bit with the seasons. It would just rise and set only once a year. Now if the earth stopped rotating altogether, the sunrise would be in the "Westerly direction", since the direction of both rotations (seen from say the North Star) is in the counterclockwise direction. The same mechanism that causes summer and winter in the higher latitudes gives rise to this changing direction.īut as for the fundamental question: the rotation of the earth about its axis is much faster than the rotation of the earth about the sun - so the rotation of the earth is dominating the direction of the sunrise. The reason for this is the fact that the earth's axis of rotation is not perpendicular to its plane of rotation about the sun (the ecliptic). For example, today's sunrise/sunset directions in Umeå Sweden, look like this (source: The yellow line shows the direction of sunrise, the orange line the current direction of the sun, and the red line the direction at sunset.Īs you can see, the sun never gets close to being in the East. In northern latitudes, during the summer, the sun rises significantly North of East, and in the winter it rises in the South. Whether the sun "rises" in the east depends on your position on earth, and the time of the year. ![]()
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