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How often do all the planets align?

Answer 1

When three or more planets appear 'to fall in line' we say 'they align'. When the planets appearing in a line are joined by straight lines, in order, the configuration will be a space polygon..

The unusual five-planet alignment that we recently witnessed is caused by the lines of the directions to the planets (at varying distances in AU unit) are very nearly coplanar. Near perfect alignment in a straight line is possible for the triad Moon, Earth, and Sun. These events are called Total Lunar/Solar eclipses. This space polygon connecting all eight planets that orbit in different planes, and orbits of different sizes, would never appear to be aligned.

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Answer 2

John Alexander

A near-perfect alignment of all the planets in the solar system occurred last in 561 BC, and the next one is expected to happen in the early 27th century. All the planets align very infrequently, usually once every few centuries.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.