How would tides be different if the Moon revolves as fast as the Earth rotates?  

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The ocean tides on Earth are the result of several complex astronomical factors but the gravitational affect of the Moon is their primary driver.  The Earth rotates on its axis once per day.  The Moon revolves around the Earth once every 27 days (approximately).  The tides on Earth occur on very regular intervals.  The period for one of these intervals is the amount of time it takes for the Earth to make a single rotation with respect to the Moon (about 12.5 hours).  During that time, whatever side of the Earth is on the same axis as the Moon will experience high tide and whatever side perpendicular to the axis of the Moon will experience low tide.  If the Moon revolved as fast as the Earth rotated, then the same side of the Earth would be facing the Moon at all times.  As a result, the tides would basically not change through the course of a day but basically stay the same.  The same  areas of the planet would experience high tide at all times and the other areas of the planet would experience low tide at all times.  In reality, there would still be some tidal change due to other factors like gravity from the Sun, but basically the tides would be essentially unchanging at all times for the entire planet.

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