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I mean, it makes some sense if there was a big bang X years ago, that everything ends up withing X lightyears of each other. I find it easy enough to think of
by Tyr42 8y ago
I mean, it makes some sense if there was a big bang X years ago, that everything ends up withing X lightyears of each other.
I find it easy enough to think of there being a beginning, since we know that stars age, and use up energy, so they can't have been running forever.
Since we think the big bang was 13.7 billion years ago, we can put Y at about 2*13.7 billion light years across as a first guess. Though there's something funkey with the spacetime stretching or whatever. So maybe more.
- resource0x 8y agoStars cannot run forever, they explode eventually, and other stars can form from the debris: https://www.quora.com/What-is-a-third-generation-star?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa https://www.quora.com/What-is-a-third-generation-star?utm_me... For the Universe having certain age - I don't understand it, b/c whatever is 13 billion years for one, might be 1 sec for another, due to relativistic time dilation. I think of this number as a kind of metaphor :)
- neolefty 8y agoBut eventually a region runs out of fusable (fuseable?) matter (Hydrogen / free protons). https://en.wikipedia.org/wiki/Elliptical_galaxy https://en.wikipedia.org/wiki/Elliptical_galaxy
- michaelcampbell 8y agoLots more. https://en.wikipedia.org/wiki/Observable_universe#Size https://en.wikipedia.org/wiki/Observable_universe#Size Of particular note to your post: https://en.wikipedia.org/wiki/Observable_universe#Misconceptions_on_its_size https://en.wikipedia.org/wiki/Observable_universe#Misconcept... (#1)
- Tyr42 8y agoYeah, but in my defense, 46 billion is the same order of magnitude as 13 billion. And a lot easier to understand why it'd be around that magnitude without the stretching of spacetime.