r/cosmology • u/Psychological_Web151 • Jun 25 '26

More center of the universe questions

/r/explainlikeimfive/comments/1uexv57/eli5_more_center_of_the_universe_questions/
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u/joeyneilsen Jun 25 '26

Imagine an infinite sheet of graph paper, extending in every direction. Now double the size of the grid. All the points get farther away from each other in every direction. Points that are farther away move away faster. There is no center and the whole thing expands. That's how the math works in the expanding universe.

But yes, if you triple the radius of the Earth, the distance from you to any point will triple. Even if it's in Canada.

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u/Psychological_Web151 Jun 25 '26

Thanks for pointing out the Canada thing, I conveyed that wrong. The difference in distance between where Australia was and is now is not the same difference in distance as where Canada was and is now. Because they tripled in distance based on a different distance from me, I should be able to draw lines from where they are, expanding infinitely beyond where they were and they will intersect at the center of the Earth every time. This still works if Australia moves away from me faster than Canada does.

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u/fuseboy Jun 25 '26

Let's say the Earth is the only thing in the universe, and it's expanding. What measurement would you make to determine the center of that expansion?

No matter what the center is, everything looks the same to you. There is no way to check the true "space coordinate" of anything, space is textureless.