The Universe is a Watermelon

https://www.nature.com/articles/d41586-019-02417-7

To get an idea of what the Universe looks like from Earth’s perspective, picture a big watermelon. Our Galaxy, the Milky Way, is one of the seeds, at the centre of the fruit. The space around it, the pink flesh, is sprinkled with countless other seeds. Those are also galaxies that we — living inside that central seed — can observe through our telescopes.

What do the @physicists think about this latest claim from Nature.

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The first three paragraphs of that article is a joy to read. I have never came across that analogy (Universe~Watermelon) before, but will start using it now.

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Start all your talks with, “just to let you know, the universe is a watermelon…”

Did you notice @PdotdQ, that this watermelon is geocentric?

It only looks geocentric because the author is using a typical physicist trick: change of coordinates :slight_smile: .

We believe that the universe is largely isotropic (looks the same in all directions) and homogeneous (looks the same everywhere), so we are justified in choosing a coordinate in which the Earth is at the center. However, note that any other place can also be chosen to be the center.

Contrast this to geocentricism, in which only the Earth can be at the center.

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I dunno @PdotdQ. According to Nature, we are the “central seed.” :crazy_face:

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I like it. It’s a cute analogy. Although, for philosophical/theological considerations, we’re less interested in things that the 21-cm radio waves can detect. We’re really more interested in times before the CMB and spaces beyond the cosmic horizon - on the things outside the watermelon’s green rind.

So I guess if I had to pick at a flaw of this analogy, I’d say that it’s the implication that the watermelon is the whole universe.

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I agree. We don’t know how large the unobservable universe is, and as you move from the center you move back in time. This creates the false sense of a boundary, which we have not yet observed.

This seems appropriate.

:slightly_smiling_face:

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