Think of the universe as a painting. There’s the image made in paint, and the surface it was painted on. The canvas.
The stars, the planets, the gasses, the matter and energy and even the space between are the paint. What’s the canvas? Is there a canvas? Would the canvas follow the same rules as the paint?
MajorMajormajormajor@lemmy.ca 6 months ago
I believe what you are looking for is spacetime which is the foundation that all of the universe exists on. My layman’s understanding is that objects with mass “curve” or “bend” spacetime around them and this is actually how gravity effects objects. An object moving along a straight path (from it’s perspective if on a small enough scale) which is actually following a curved path of spacetime will move in a curved path.
Image
This gives a visual representation of the curving of spacetime.
Image
This shows how a super massive object like a white dwarf or black hole distorts and eventually “breaks” spacetime.
themeatbridge@lemmy.world 6 months ago
Excellent comment, love the diagrams.
But we know spacetime is getting bigger, because the universe is expanding. So what is spacetime expanding into?
MajorMajormajormajor@lemmy.ca 6 months ago
Who knows? Are we in a bubble floating in a higher dimensional sea of different bubbles? Is it nothing, like a balloon expanding in the vacuum of space?
oo1@kbin.social 6 months ago
As i understand it it (somewhere between barely and not at all) the idea is not that It's "expanding" in the sense of a balloon inflating into the space around it.
Its more stretching internally.
So the distance (or time it would take at constant speed) between any 2 points is geting bigger.
You could maybe also say it'd take more energy to move between the points in a set time.
There's probably nothing outside, but the distances inside get longer.
It's probably something to go with gravity, momentum and entropy. The actual concept of "distance" between things might not be what we think.
But all these theories give rise to the concet of large amounts ob unobserved 'dark' mattter and evergy, so the actual basis of currently observable fact (i.e. energy / mass) is a small fraction of what is needed for these theories to work.
Kolanaki@yiffit.net 6 months ago
How do quantum physics play with spacetime?
I’m probably not asking the right question for what I mean… For context, I originally thought of the question when reading a science post on quantum physics vs general relativity and how they don’t mesh and wondered “could we be seeing the medium simply behaving differently than the art?”
MajorMajormajormajor@lemmy.ca 6 months ago
My understanding is that quantum physics is the study of the incredibly small, and general and special relativity are the study of everything else. They don’t overlap (rules for big don’t work for small, and vice versa) and are two separate understandings. Which is why the, hopefully, next big thing will be a unifying theory that applies to everything. I believe Stephen Hawking was a well known scientist working on finding a universal theory.
Which doesn’t really answer your question, but it’s a question far surpassing my knowledge. I think quantum mechanics just doesn’t interact with spacetime, or at least not in a meaningful way (mass of an electron is so incredibly small it isn’t perceptively effected by spacetime curves).
I would be happy for someone with more knowledge to come and prove me wrong though, these are fascinating fields.
Gerudo@lemm.ee 6 months ago
That is the key to almost everything. Quantum mechanics is neat and tidy. Space time is neat and tidy. They don’t play well with each other, though. Some scientists say that we need to figure out dark matter and dark energy to make them play together. Others say they are so incompatible that we need new science altogether to figure it out.
bartolomeo@suppo.fi 6 months ago
In the first picture, the object in orbit is travelling along, say, y=0. There could also be an object in orbit along x=0, right? So that would mean there isn’t a “canvas” or 2D equivalent, since things can orbit at any angle. Is that right?