The Challenge of Relativistic Spaceflight

Third can be used both as a noun and an adjective.

Noun form: "A third of a pizza".

Adjective form: "A third pizza".

I think we'll need fusion to make intra-solar system travel (really) possible, where we just transport stuff through-out the entire system, with a speed of at least 1/100 of the speed of light. Achievable in ~50-100 years.

For inter-stellar space travel, say to the closest 20-100 star systems, we'll need either an anti-matter powered ship or a black-hole powered one (a bit more likely) that can travel to these stars in only a few years to a decade, and then another few years to a decade back, with the speed of 30-50 percent of the speed of light. Achievable in ~200-300 years (remember technological progress is exponential not linear).

For whole galaxy exploration we'll definitely need something like a warp engine. When we'll get this is harder to predict, but it will probably take at least 1,000 years to do it.

Things that could definitely help with space exploration: figuring out immortality against aging, which could also make us more interested in 100-year old projects, transferring our consciousness to machines/more resilient avatars not just for space travel, but also for living on new dangerous planets, and quantum Internet so we can rapidly communicate through long distances.

If we do the last one, we might not even need to travel ourselves or transfer into other bodies, to go to those places. We'd just send robots that we control absolutely and very precisely, just like we were there (Avatar/Surrogates-style).

> (remember technological progress is exponential not linear)

No it is not. For example, airliners fly about as fast as they did a generation ago, and if you buy a desktop computer today it won't be noticeably faster than the ~3 year-old one you're using now.

Do you really think the next TV you'll buy will be exponentially bigger than the one you have today? Prepare to be disappointed.

warp-engine would require FTL travel, which is not possible. How can you travel a distance less than zero? At C all distances are zero.

DNA is already a pretty good way to travel the stars, a human ovum (the largest human cell) has a low enough mass to get out of Earth's gravity well using only electrostatic or solar-pressure forces, no fuel required. If it were somehow interstellar-vaccum-hardened and able to modulate the energy gradient it uses to change direction, it could travel to the stars.

I suppose you have misunderstood quantum entanglement, as it does not offer any way to communicate instantaneously over vast distances. It's more like when the light-standard in front of you turns green, you know INSTANTANEOUSLY that the "entangled pair" light-standard perpendicular to your view is red.

How would the ovum develop and be nurtured? Sympathetic alien surrogates?

Why not seed more simple lifeforms, such as genetically modified bacteria, upon hundreds of "candidate" planets so that by the time our generation ships arrive there's a good chance some basic terraforming has already occurred.

Is continually accelerating at 9.8 m/s^2 necessary? Sure, that's what's needed to get off the ground, but it seems excessive for a whole interstellar journey.