* No Perfect Alignment: The planets in our solar system don't orbit the sun in a perfect flat plane, and their orbital paths are slightly tilted. This makes a perfectly straight line impossible.
* "Alignment" is Relative: What we consider "alignment" is subjective. A loose alignment where planets are close together in a section of the sky happens more frequently than a precise, perfectly straight line.
* Long Orbital Periods: Planets have different orbital periods. It takes a long time for them to cycle back to a similar configuration, even if we define alignment loosely.
However, we can say:
* Rare Occurrence: A close alignment of multiple planets is relatively rare, happening on the order of centuries or even millennia.
* "Great Conjunctions": We do have what are called "Great Conjunctions" which occur when two planets like Jupiter and Saturn appear close to each other in the sky. These can happen every 20 years or so.
So, it's not about a perfectly straight line, but rather about how close planets appear to each other in the sky. And even that kind of "alignment" doesn't happen often.
