Here's why:

* Orbiting on Different Planes: The planets don't all orbit the Sun in the same flat plane. Their orbits are slightly tilted, making perfect alignment impossible.

* Different Orbital Periods: Each planet takes a different amount of time to orbit the Sun. This means they are constantly changing positions relative to each other.

However, there are times when planets appear to be close together in the sky from our perspective on Earth. These events are called planetary conjunctions.

Conjunctions can be quite spectacular, but they aren't true "alignments."

To get accurate information on upcoming planetary conjunctions, check astronomy websites like:

* NASA's website: https://www.nasa.gov/

* EarthSky: https://earthsky.org/

* Space.com: https://www.space.com/