Space travel

Writings concerned with ETI almost always admit that interstellar travel is not only possible within the limits of what we know and can project but that advanced civilizations could probably manage it if they were so motivated. It should be enough for us to learn from history about the absurdity of assuming that we know what our absolute technological limits are. But if vague intuitions about history aren't enough, we need only to look at the present. Any serious perusal of the writings of Robert Forward, among others, should convince a reasonable person that even extensions of today's technologies could achieve travel to the neareast stars in travel times of twenty or one hundred years s1Forward 1984, 1985. Nuclear fusion designs and lightsails seem most concrete, and anti-matter engines are much written about as well s2Forward 1982 s3Bond 1977 Winterberg 1983. Certainly we and others will uncover other methods as our knowledge progresses.