I wonder if this is a factor limiting interstellar travel. Where spaceships are not able to approach light speed because they will quickly accumulate a ton of space grease.
https://www.theguardian.com/news/2017/jul/28/is-the-world-re...
It could just as well be true for all of them as well (assuming it is for the rest of course).
The "but now X group has rights" argument doesn't mean much. Such rights are a small, and rather insignificant part of life. Women, gays, lesbians, and racial minorities had huge great movements and tons of fan in the 70s in their everyday life as well. It's not like their whole existence was diminished by how others conceived them or whether they had this or that law.
A black who had a steady Detroit job in the 70s in a nice home, family and so on, felt much better off than an unemployed same-aged man in Detroit today, even if the second has more nominal rights and articles about him now (not to mention that there are probably more police shootings of blacks today than in the 70s, and let's not even compare Trump to Carter or even Nixon on that regard).
Or go talk to gay people, and see how they feel about the 70s and 80s, and various scenes that existed then compared to today. You'd be surprised Living in a looser and laxer decade can be more important than having some right in some law book (gays then partied far more widely and extravagantly than the meagre contemporary scene where they have rights, sure, but society is run by prudes and money spoilt most scenes).
Heck, in the same period we had a full blow military dictatorship in my country, and people can still wax poetically about the times and the fun they had. Even people persecuted then and even tortured by the police at this point or another.
It's probably no more a factor than how thick the paint is on the hull.
The whole thing is also a case for building spacecraft with as small a cross section as possible, less chance of hitting something large.
A long spear is an even better shape, though.
Low density regions of interstellar medium can have as few as 10e-4 particles per cubic centimetre. At 0.1c, that density works out as 3e10 particles/m^2/s. At that density and energy per particle, 0.0895 W/m^2. Low enough you wouldn’t care.
Molecular clouds, on the other hand, can be up to 10e6 particles/cm^3. Most of those molecules are hydrogen, so they don’t hit as hard on average… but that’s a rounding error compared to the density, so let’s say about half a gigawatt per square meter.
TL;DR — go around the molecular clouds until you invent a Trek-like navigational deflector.
It’s a great series, but it’s not hard sci-fi, just a great storytelling mechanic.
At best, it sometimes tried, depending on the writer, to make nods to actual science. The original series seemed to have input from actual engineers and scientists, which is why you have the nacelles separated (to protect from radiation) and Bussard collectors, but then as time went on, it sort of became magic particles and subspace and not even bothering with the pretense.
Call it a distributed probability modulation drive. Just don't get entangled in the math.