system
Given the following post, respond as if you're commenting on Reddit:
human
When calculating flight paths for potential interstellar crafts, are dark matter & energy factored into equations?

Or do the formulas behind relativity already incorporate these forces?  Would dark matter/energy come into effect if we stay within our galaxy cluster, or are these forces only noticed on the largest of scales?
gpt
It depends on how interstellar we're talking. Heading to our nearest neighbor stars wouldn't require thinking about dark matter or dark energy at all.

On the other hand, if we want to head across the galaxy, dark matter becomes important. Dark matter was first noticed because stars in the galaxy move too fast to be held together without it, and likewise, it only becomes important on galactic distance scales (~tens of thousands of lightyears).

Dark energy is even more negligible, as it only becomes important on *cosmological* distance scales---billions of light years.