(spaceships) rocket (super)science

[Johnny1A.2]

Originally Posted by jacobmuller

Inertia is telling me I should just accept that space travel is going to take a while - excepting the "jump drive" option.

It depends on your assumptions.

As far as we know now (emboldened because humility is important), the iron limit on travel time is the velocity of light. You just can't get there any faster than that (assuming causality is maintained and that relativity is the last word).

For interstellar travel, that means years, decades and centuries or more. No way around it (as far as we know).*

For interplanetary travel, the speed of light is not that big an issue. It only limits you to interplanetary trips in hours (or months if you want to go out into the cometary halo).

There is no law of physics that says you can't travel from, say, Earth to Saturn, in well under one day. It only requires energy sources and propulsion systems in excess of anything we know how to build.

The issue with postulating one-day trips across the Solar System is that if you have the energy resources to do that, then you can do a whole bunch of other things, too, that you might not want to deal with in a setting.

* I keep emphasizing the 'as far as know' because you can't know what you don't know. Imagine a group of Bronze Age thinkers trying to imagine travelling around the world in a few hours. It would seem as self-evidently impossible to them as FTL travel does to us. Many of them would not even be conceptualizing the world properly as they considered the matter (flat vs. round). Our own understanding of the universe might be equally erroneous, we can't know.