3 ms·
Imagine you're inflating an air balloon, first to a size of an apple then size of your head then to enormous like a weather balloon. Now consider that the surfa
by varjag 3y ago
Imagine you're inflating an air balloon, first to a size of an apple then size of your head then to enormous like a weather balloon. Now consider that the surface of balloon is the space: points on the surface get further and further apart but there is no edge or boundary.
- sillysaurusx 3y agoHow is it possible to say with any certainty that the universe was the size of an apple? That analogy also implies that space wraps around, which no experiment has ever shown to be true. This contradiction is why I have trouble. It’s a good analogy otherwise, but the details are the interesting part.
- varjag 3y ago> How is it possible to say with any certainty that the universe was the size of an apple? Haven't read the paper but one likely could tell from the density. > That analogy also implies that space wraps around, which no experiment has ever shown to be true. It's an analogy meant to highlight one particular aspect, not be a perfect model of spacetime. In mathematics, there is no shortage of topological objects that are infinite but not closed otherwise.
- theferalrobot 3y agoWouldn’t that be more applicable in a universe that wasn’t flat (unlike ours as best as we can measure).
- varjag 3y agoThere is also no air inside and nobody's actually blowing. It's an analogy.
- theferalrobot 3y agoIt is an analogy that is used to describe spacetime curvature though… its the wrong analogy.
- varjag 3y agoNo it's an analogy used to describe inflation with no boundary.
- oneshtein 3y agoAir balloon has clear boundary.
- consilient 3y agoThe volume enclosed by the balloon's surface has a boundary, the surface itself does not.