I mean its all speculation anyway, it's physically impossible to accelerate to the speed of light, to fuel a ship to even approach it, to find a source of energy that can produce infinite power, etc.
It's all perpetual motion machines, matter replicators, infinite energy machines, magic.
But even pretending that any of it were possible its not even space dust you need to worry about. The electromagnetic force that holds atoms and molecules together only moves at the speed of light so your fucking space ship would fall apart the moment you hit c anyway, regardless if you even hit anything.
Figuring out ways to shrink things that can't be shrunk (blackholes) so you can fold spacetime or figuring out how to move faster than matter can move (ftl) is all just mental maturation.
Aldarion is correct that generation ships are the only way we leave the solar system and we'll have to make very frequent stops to refuel (ice belts), and thats once we figure out a renewable source of gas for ion drives, there aren't gas stations to refill xenon tanks in space either. We only do it if the solar system is going to no longer be habitable, that's why no aliens have colonized the galaxy yet.
Good news is we know that shit doesn't work, cus if it were possible it would have already been done.
In theory, couldn't you make a particle accelerator that pushes hydrogen atoms out the back at 0.9-0.95c which is then powered by a fusion reactor that also uses hydrogen for fuel - granted, this is limited fuel, but with the specific impulse you'd get from that type of exhaust velocity and the length of time you could power your ship with a few hundred tons of hydrogen, it could go pretty well depending on how small/light you can make a particle accelerator, how many atoms it can accelerate at a time, and how small/light you can make your fusion reactor. These seem like engineering problems though not exotic physics. You'd need to ionize your hydrogen so that you could use electromagnetic particle accelerators, and you could exhaust a proton beam directly just like rocket exhaust now.
Obviously you'd have to hugely scale up particle accelerators to be able to have decent thrust for a ship of any scale, but again this seems like an engineering problem. I ran some numbers on Grok (trigger warning) and came up with the following:
With a 10 TW fusion reactor and a particle accelerator exhausting protons at 0.95c, the spacecraft can have a
total initial mass of approximately 120,240 kg, including
75,240 kg of hydrogen fuel and a final mass of 45,000 kg (40,000 kg for the reactor and accelerator + 5,000 kg payload). The mission achieves a total proper time of ~18.21 years to reach Alpha Centauri (4.37 light-years), with an accelerate-coast-decelerate profile reaching v=0.995c. The 10 TW reactor provides sufficient thrust (~333,800 N) to make the mission feasible within the 10–20 year proper time goal.
I had it assume the particle accelerator and fusion reactor would each weigh 20 tons. In reality, who fucking knows, we're talking future tech. A 10TW reactor is also completely insane-balls power, but just saying, this is engineering, not fantasy shit. And since this ship is accelerating to .995c, you could actually go a lot of places, not just Alpha Centauri, and the onboard ship time doesn't change "that" much due to time dilation.
Edit: I had Grok recalculate for an exhaust velocity of 0.9999c since I just made up 0.95c thinking it would be less power intensive, but it's not. Actual particle accelerators accelerate protons to 0.99999999c today, so if you re-do the math for a 0.9999c exhaust speed rocket with the same 10TW reactor you cut the fuel mass needed tremendously:
For the same final mass mf=45,000kg, the fuel mass drops from
75,240 kg to
4,725 kg, and acceleration time to 0.995c decreases from ~9.07 years to ~3.75 years per phase, significantly improving mission feasibility within the 10–20 year proper time goal. You could add a lot more payload for the fuel mass you can cut out.
