J.C.MacSwell

There is no reason to believe that we are that rare at this point. If the nearest "somewhat like ours" solar system had some species that had advanced to our level, would they know we exist? We have a long way to go just to get in the game, to be considered one of the "they" in someone else's "where are they?".

They are often used interchangeably, but also generally used in different contexts. Say for instance, referring to the motion of a boat at sea vs the movement of a boat at sea. The first would refer to the pattern, and the latter more the displacement.

That would require interaction with something other than the ensemble, correct? (I'm guessing) Also, what would a typical ensemble consist of? Is this where you meant massive particles?

I think this is where he seems to have trouble.

If you want an entertaining non technical overview I recommend this: http://en.wikipedia.org/wiki/In_Search_of_Schr%C3%B6dinger%27s_Cat

That was my impression as well Good question. Non - locality really messes with causality and time. I have no idea how string theory might solve that. Having said that, I can't make sense of it without extra dimensions either.

Here's my attempt from a few years back (2005):

Yes, but you have the bold part backwards-it would be far easier (not less easier) to get something in orbit spinning the same direction as the Earth as apposed to the opposite direction

You still have background radiation, from every direction equally in the frame of the cmbr isotropy where all your stars, planets etc. pretty much reside. While insignificant for short durations at low speed, maintaining significant speeds wrt to that, for long periods of time, requires significant amounts of energy and mass for propulsion.

Considerably less but maintained for hundreds of years (for an extremely "local" trip on the scale we are discussing), not just the days or weeks required to get up to (and down to) speed.

Just to add: If that is it, "huge man taking steps", then describing his step as 299792458 m means what? I can do that with respect to some frame, take ten 299792458 m steps, measured in a frame that is moving almost c wrt me, in one second of my time, but wrt that frame I am still moving at less than c. I can easily produce a speedometer that will register 10c. I simply scratch out kph on the display and replace it with "c" and it will accurately measure your description of "proper velocity" in some frame's distance and my time, but unless you recalibrate your speedometer to do this it will never register 10 c.

You described what you claim it does. Unless you believe you have a "huge man taking steps" somewhere in your vehicle you've made no attempt to describe your speedometer.

That theoretically gets you up to speed. How do you maintain it?

Assuming they have the technology: Their would be considerable resistance to maintaining 1/6 c wrt the cmbr isotropy. Trying to maintain 5/6 c would take many times that same mass and energy, What sources of mass and energy can be harvested at that velocity with any efficiency? It may simply be that "they" are all still back close to home.

Seriously. Are any? The OP seems to claim they are.

Describe your speedometer. I can't see how any speedometer, even using ideal assumptions, would measure proper velocity as you describe it.

Generally the 3 blade has the advantage, other than start-up. If you slow the wind too much in an attempt to get more power, you actually end up with less, as the upstream wind is diverted around the swept area of the blades and that energy with it.

Thoughts on the speed of that: That's 1/6 of lightspeed, or almost that, accounting for the 3 billion years of expansion. (that's colonization speed, not just travel) How much energy is required to maintain 1/6 c , never mind achieve it, with respect to the CMBR isotropy? How much hotter and intense was the CMBR back then, 3 billion years ago? Wouldn't colonization generally require round trips, or at least decelerating/accelerating to/from the speeds of most planets, solar systems etc, (that are for the most part locked to the CMBR isotropy), for refueling and at least a minimal amount of hunting/gathering for maintenance, re-manufacture or refurbishing of whatever it is that will be moving on?

Which measures "round trips" of some point in the wheel from the frame of the vehicle. Correct? To OP et al: I realize it is just accounting, but a corresponding point on the perimeter of the rigid ideal wheel must make that round trip as well. This point can never reach c in that frame, so the speedometer cannot register a speed of c or greater. I understand the approaching infinite pseudospeed by using the time frame of the vehicle and the "yardstick" of the point on wheel the nearest the road, frame mixing as Swansont mentioned, but I don't think any vehicle speedometer is set up to do that. A device would have to stay continuously at the point of contact with the road, while also spinning with the wheel, which of course it cannot do.

1. rotational speed measured in the time frame of the vehicle multiplied by the wheel circumference measured when the wheel is at rest (or some other preset distance) 2. no 3. yes

Exactly. No shooting below the waist. Also, no baseball bat to the head.

Rail gun + hollow tube with vacuum (less drag and no "mach/shock" concerns), either timed to open/close at the top with passage of the rocket, or simply long enough to reach space.

Just make sure they have fat on them. http://en.wikipedia.org/wiki/Rabbit_starvation But by any means cook them. Avoiding parasites and diseases is usually more critical than a lack of vitamins.

OK we get the balloon and Hydrogen up there; how much oxygen is available from the rarified air to burn the hydrogen and propel us further?

All other things being equal twice the mass can absorb twice the momentum (or for that matter twice the energy) in the same way. Normally a "projectile" would have it's momentum absorbed, rather than the other way around, but the principle still holds.