There is no such thing as a planetary alignment that occurs every 100 years. The planets in our solar system orbit the Sun at different speeds and in different planes.

Here's why the idea of a regular 100-year alignment is incorrect:

* Orbital Periods: Each planet has a unique orbital period, the time it takes to complete one full orbit around the Sun. For example, Earth takes 365.25 days, Mars takes 687 days, and Jupiter takes about 12 years.

* Different Planes: The planets don't orbit in the same plane. They are slightly tilted relative to each other, meaning they rarely line up perfectly.

* No Fixed Pattern: Due to these variations in orbital speeds and planes, the positions of the planets are constantly changing, and there isn't a predictable pattern where they all align in a specific configuration every 100 years.

While the planets do align in a rough sense from time to time, it's not a regular event, and it's not something that happens every 100 years.