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The ant and balloon analogy is really good from an intuition stand point. Great explanation! Well done :)


As light is travelling within the expanding universe does the wavelength of distant light change over long time periods or does it appear the same because our observations are expanding too(my head hurts)>


Yes, the wavelength gets longer. That is, in fact, how we measure the distance: for a known frequency (say, the electrons jumping up and down in a hydrogen atom), we observe that this color is "redder" the further away an object is. The number "z" mentioned above is called the redshift because of that, and it's how we know the distances of the furthest objects.


Except for fact than in balloon analogy, ant is moving in a direction by balloon surface, while in our case our "balloon" is perfectly still in all directions.

Imagine that balloon is not inflated at all, but ant magically moves 70mm instead of 10mm. How this is possible???

I can accept, that our part of Laniakea is expanding, but not whole Universe.


Sometimes I say as joke that in reality the universe are not expanding but the things inside that are shrinking.


What'll really blow your mind is that it's expanding faster, not slower.


It kind of makes sense to me with some further caveats to the analogy.

If you think of the ant as a 2 dimensional creature living on a two dimensional surface of the balloon, the expansion is occurring in 3 dimensional space. The two-dimensional ant has no way to observe the space north or south (above and below, to us) its plane of existence.

Now, imagine that the balloon is in a vacuum. It had a burst of air (the big bang) for a moment to get it started but it's not the further addition of air that's driving the expansion, it's the desire to equalize pressure between the exterior vacuum and the interior matter.

With that in mind, push everything up a dimension. We're 3 dimensional creatures living in a 3 dimensional universe. That 3 dimensional universe exists as a plane in 4 dimensional space.

The 4 dimensional balloon (that our universe is surrounding) is continuing to expand into the "nothingness" on the ana plane of the 4th dimensional universe because of the "pressure" imbalance on the kata plane of the 4th dimensional universe. (In 4th dimensional spatial terms, ana and kata indicates directions on the w axis, similar to up/down on the x axis, left/right on the y axis, and north/south on the z axis)

At least, that's how I see it in my head, but I'm an odd ball who has never had a problem intuitively visualizing 4th spatial dimension objects and how they might interact with 3rd dimensional space.

As for the increased speed of the expansion... actually, I hadn't thought about that. Does it indicate that equilibrium will never be found? The balloon analogy might be a useful tool, but our universe isn't made of rubber so it might have the capability of being able to expand infinitely without breaking and without its "nature" constraining the expansion speed.

Anyway, if this is a reasonable analogy, the "nothingness" in the ana direction isn't as interesting to me as what might comprise the "pressure" that's in the kata direction that's causing the expansion. It's nothing we'd ever be able to observe or sample since it's outside of our plane of existence, but it's awfully fun to speculate about the composition and nature of it.




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