A Universe of Bubbles

A bubble model may explain observations but gravity is required to make a bubble rise.

Or accelleration.

Or hot air!

I haven’t even commented yet!

Seems to be a lot of bubbles around DC.

Of course, when an alligator farts it will create bubbles.

Interesting idea but I don't think universe really have an outside or pressure like a bubble.

A pressure difference between "inside" and "outside" is not enough to explain why a bubble moves. We need a pressure differential/gradient for buoyancy to emerge. So, if the bubble moves, we have to explain why this gradient exists in the first place. It should be created by a force, right? Therefore, we try to remove the need of a force to explain expansion of the bubble, by assuming a force outside it.

Even if the bubble does not move, i.e. the outside pressure is spacially constant, we will have to assume temporal pressure change. This again requires an explanation.

In few words, I think that with just sweep the problem under the carpet, by delegating the cause of natural phenomena to super-natural agents (i.e. ones that lie beyond the Universe and its Laws).

Another issue I find in the logic, is that you assume that space-time exists outside the Universe in order to "give-way" to the expanding bubble. But is there any meaning for space-time to exist outside the Universe, since most probably it was created along with it? Otherwise, if there is space-time outside our Universe, then what separates it from the "outside" non-Universe world?

You said “It’s just not time and distance that prevents star travel, it’s that we can not observe stars in real time. We don’t know where they are now, and we don’t know where they’ll be in years when we get there.”

I dunno about that. Time and distance are pretty large hurdles for us to clear on a trip to Mars, and we have a pretty solid grip on the orbital mechanics of the planet.

The Voyager 1 probe is approaching one light-day from Mother Earth, 49 years after launch. As you say, time and distance are not the only things preventing star travel, but with technology available today these are problematic and persistent obstacles.

When light distance is short and the change in displacement(source V) is slow, the true location of the source, can’t be far away from where we see and detect it. And only a few course corrections are needed.

Our closest star is ~3LY away. And if that star is like ours, it’s going much faster than our planets. AND our crafts. And of course Sol is going much faster than the planets. Our craft will have a Sol’s V. component.

Following that other star’s light will take continuous course corrections. Lot’s of power. And lot’s of more time.

The only way to get there…. Is to know where they’ll be. ONLY one unique path. To a star.

Just a hayfield opinion, I’m no expert.

At present I think star mechanics, and so star navigation, is beyond us.