It is not possible for all the planets to ever be fully aligned. However, sometimes cosmologists and scientists will speak of planetary alignment, and when they do this they don’t speak about 100% alignment, but rather refer to a state where all the planets of our solar system appear to be in the same rough position in our night sky (the same 180-degree wide pane of sky).
The Process of Planetary Alignment
The planets orbit around the sun at different orientations and tilts with the effect that they can never come into perfect alignments. Sometimes, all the planets of the solar system will appear in the same rough area of the sky, but this hasn’t happened since 949, and won’t happen again until May 6th, 2492.
Sometimes, in intervals of around fifty years or thereabouts, the brightest plants in the night sky will position themselves in such a manner as to appear that they are in a straight line. The last time this happened was in April 2000, when Venus, Mars, Saturn, Mercury and Jupiter appeared above the western horizon in the shape of a necklace, and such an event won’t happen again until 8th September 2040.
Effects of Planetary Alignment
Over the years, partly as an effect of the storylines bandied about in sci-fi books and films, there have arisen certain misconceptions about the effects an alignment of the planets would have on Earth, with a certain portion of people claiming that planetary alignments would adversely affect our weather patterns gravitational pull, and in some cases, even the movement of the continents. The gravitational pulls of the planets can’t affect the Earth since they ae too far away to have a significant effect on our planet. The total gravitational force that acts on the Earth when the planets are at their closest possible distance to the Earth is 0.000064 Newtons.
Occasionally, doomsayers will prop up with wild claims to the effect that when the planets all align the Earth will be destroyed, but a counterpoint to this claim is to point out that in the roughly 5 billion years of the Earth’s existence the planets have been aligned before but the Earth has not been destroyed. And as has already been showed above, it is impossible for all the planets to ever align perfectly, but even if they were to align perfectly, the other planets of the solar system are too far away from the Earth to have anything more than a negligible effect on the Earth.
Future Dates of Planetary Alignments
September 8th, 2040: On this day the planetary orbits and movements of Saturn, Mars, Jupiter, Mercury and Venus will be such that they will appear to be aligned in a straight line.
May 6th, 2492: Scientists have a theory that this is the closest possible date when all the eight planets of our solar system will appear to be aligned.
In conclusion, we must note that will it is impossible for the planets to ever perfectly align (because of their different tilts), sometimes they will appear to be in the same rough area of sky. However, because this is nothing more than appearance dependent on perception, one has to be at a particular point for them to appear to align.