Consider a 4D sphere, for which you can only see a 3D cross section as a 3D creature. If every part of the inside of the sphere were dyed a different colour, it'd look as though the slice were changing colour, when in reality, the colours are merely passing in and out of the slice. In the case that the axel is contained completely in the slice, this axel will be fixed in the slice, while every other part of the sphere passes in and out through the slice. If your 2D slice were instead parallel to the axel of rotation, it'd look quite different. When you combine all of these 0D points, you get the whole 1D axel of the spinning 3D sphere. If you were to take a 2D slice of this 3D sphere, where the slice is perpendicular to the axel of rotation, you would see a 2D circle of various sizes (depending on how close your slice is to the equator) spinning around a fixed, 0D point. We fix a 1D axel around which an object spins. Now you might argue that this pin is 1D since it is a rod, but it fixes only a single point on the paper to the board, making it 0D if you were to focus on the 2D world of the paper and bulletin board. If you pin a sheet of paper to a bulletin board, you fix a point on the paper around which it spins. Since these circles are perpendicular to the axel, if you rotate something in nD space, the axel will be n-2 dimensional. The axel of rotation is defined to be the points that stay still throughout the rotation (if you're familiar with linear algebra, this would correspond to the eigenspace corresponding to an eigenvalue of 1 in the rotation matrix). These circles are 2D, no matter whether you're in 2D, 3D, 4D, or any nD space for n≥2. Rotations are really a bunch of parallel circles spinning around an axel, and every one of these circles are centred on and perpendicular to the axel. What I mean by this is that there is no such thing as rotations around axes as you would think in 3D, where there's a 1D axel that remains stationary. No petitions, surveys or campaigning: Invitations to chat rooms and other subreddits, external petitions, promotional posts, fundraisers, questionnaires and external surveys are not allowed without a permission from the moderators.ĭon't think of it as rotating around a "4th axis", since such a rotation doesn't exist in 4D. Remember r/theoreticalphysics is not an "ask" subreddit.ĭescriptive titles: Submission titles should describe its content, posts with clickbaity, off topic or vague titles may be removed by the modsīehind paywall: Please try and link to open access papers if possible.Īvoid predatory journals: Articles from predatory journals are discouraged and will be flaired as such.Īvoid pseudoscientific publications: Promoting fringe science and pseudoscientific publications is not allowed be precise, give a thorough explanation and most importantly make sure this question is refutable. If you insist on asking about something you came up, make sure it fits some scientific standards i.e. Questions: All questions are welcome as long as they are not masked as a self-theory and motivate further discussion. If any of these above do not apply try r/HypotheticalPhysics.Do not try to deal with many topics at the time.You should be able to discuss its obstacles and shortcomings You give a mathematical formulation, equations are better than long paragraphs.You give a framework, cite secondary sources (not published by you) If you want to discuss a hypothesis of your own, make sure that: No low-effort: Do not post off-topic content and leave a precise descriptionĪvoid self-theories: Self-theories are discouraged. People are free to challenge your ideas, do not be defensive if your ideas are dismissed or proven wrong. Beware to post if you do not know what a Lagrangian is.īe polite and civil: Follow the reddiquette, be polite and civil. This sub does not fear maths, so mathematical physics discussions are appreciated. Professional or amateur theories and models are welcome as long as they are backed up by actual research. Remember to always back up your posts with reliable information, clear argumentation and verifiable sources. Post and discuss any commentaries, opinions or external links related to advanced research in physics.
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