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Sunsets on Mercury
 

This model demonstrates the process of sunset on Mercury. Press "Run" button to activate the model. Press "Stop" to suspend it, and press "Reset" to return the model to its initial state.

Mercury is the planet that is the closest to the Sun, and it is said to be in gravity resonance with our luminary. One solar day on Mercury lasts for 2 mercurial years. One day and one night last for 88 Earth days each, i.e., together they are equal to one planetary year.

Select the longitude of 90? or 270?. The Sun rises in the East. It slowly ascends (in average one degree per twelve hours), reaches the upper transit (or zenith at equator) and sets in the same manner - very slowly. However, the observation of such behavior depends on the position of the observer. If you select 0? or 180?, you will observe the Sun suddenly stop shortly after the sunrise, turn back, and set virtually at the point of sunrise. The Sun rises again at the same point after several Earth days, and this time, it stays visible for a long time.

At sunset, this behavior of the Sun can be observed in reverse order. This phenomenon is known as Jesus Navin effect in honor of biblical hero who managed to stop the Sun in the sky. Sunrises and sunsets are observed two times in one day in certain areas on Mercury. Three sunrises and sunsets may be observed at 0? and 180? meridians during one solar day, which lasts for 176 Earth days.

 
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