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I agree Tsurugi

The relativity laws bring you in this direction of notion, super fluid indeed!

When accelerating, a body is loosing mass. Mass is energy, so the body is winning energy on its velocity and loosing on its mass, one equals up the other, more or less.For this reason and in order to get on the "surf wave", a high powered plasma beam ( nuclear), would be more relevant as compared to ejecting away ballast materials. The influence of the beams reactive force will increase when the velocity increases, as the mass of the vessel is decreasing ( in relative terms). I can imagine a strategy for the actual "surfing", but the disapointing thing about all this is that it can never be proved to your own people, as those ancients couldn´t have proved it to their own either.

Inventor,

There was a fairly recent article I read somewhere, about a paper which noted that "spacetime" displays a lot of the properties of a superfluid, suggesting it isn't actually "empty space". (Hello, Æthere)
So perhaps some form of "paddling" in space is, in fact, appropriate, lol.
But let's be honest, paddling sucks if it has to be kept up for long periods of time. Any large body of fluid will have wave patters moving within it; if space is a vast ocean of aetheric superfluid, it too will contain wave patterns. So instead of using paddling as the primary motive force, maybe a short burst of paddling, if timed properly, would allow one to "catch" one of those waves and ride along with it.

Yes. Space surfing.

You're right, octopi are very intelligent. Giant squid also display intelligence along those lines. That article about the ancient Kraken lair, with all those plesiosaur bones arranged in patterns, comes to mind as well.
So yes, along with the Dinos and the Insectoids, Cephalopods are another possible source of an advanced ancient intelligent race.

Yes Tsurugi

The relativity formula E=mc2 and the classical kinetical energy formula E=mv2 tells you what you stated above, that if you know the trick, its really only an energy conversion, ideally not needing to much external input. When operating inside a sticky dense atmosphere, it may make sense to push media away from your vessel, in order to enjoy the reactive effect, paddling your way through it, in space it seems to be a crasy notion. Perhaps they sailed trough and utilized the gravitational and electromagnetical fields of other bodies in space.

Concerning the ant people, also think of that octopusses are a kind of shellfish, but rather intelligent as such, woldn´t you agree?

Yes. Hopefully some of those erstwhile chrononauts have figured out a way to slide around all the limitations of Classical Mechanics, so that they aren't having to hurl themselves up to reletavistic velocities in order to get any time travelling done, heh. Plus, that's only a one-way ticket, as far as I know.

As for intelligent dinos, why not? I have also sometimes wondered if there might have been an intelligent insectoid race that arose previous to the Age of Reptiles. It would explain certain aspects of the folklore of some native cultures in North America, about the Ant People and the Snake People.

Tsurugi, as I´m sure you are well aware, many of these UFO observations that occure could theoretically have been time travellers from Earth returning after such a journey with both a timevector and a spacevector or perhaps curves. Travelling at close to the speed of light , would have enabled them to return thousands or millions of years later, still within their normal lifespan. What if, there have even been intelligent dinos with a technology superceeding our present one.