Space Definition and 1000 Threads

What if the brain received simply a list of commands to execute, like a processor ? Hence all the visualization were just a creation of an internal geometry. Fatality is then unavoidable since the commands have to be executed and since the datas are one dimensional, there were no way to escape.

Hello, I am reading some material related to jet spaces, which at first glance seem to be a generalization of the concept of tangent space. I am confused about what is the correct definition of a jet space. In particular, given a map ##f: X \rightarrow Y## between two manifolds, what is the...

Below, I have already solved - I assume - correctly for question 1. Question 2, I am nearing to what I believe is the solution. Question 3, I simply have no idea where I should begin considering that it is interconnected with question 2. With that said, below is the lengthy and somewhat tedious...

How would the expansion on a scale of 10 kpc be measured, by a red or blue shift? How can expansion of space be differentiated from the velocity of stars? It seems that the expansion of space weakens the effects of gravity?

Hi I am reading Landau's mechanics So in the first chapter page 5 It reads : since space is isotropic, the lagrangian must also be independent of the direction of v , and is therefore a function only of it's magnitude ... I can't understand why , I think Landau's book has many fans in this...

To begin with, I posted this thread ahead of time simply because I thought it may provide me some insight on how to solve for another problem that I have previously posted here: https://www.physicsforums.com/threads/special-relativity-test-particle-inside-suns-gravitational-field.983171/unread...

Below is an attempted solution based off of another user's work on StackExchange: Source: [https://physics.stackexchange.com/questions/525169/special-relativity-test-particle-inside-the-suns-gravitational-field/525212#525212] To begin with, I will be using the following equation mentioned in...

I understand that the Dual Space is composed of elements that linearly map the elements of the Vector Space onto Real numbers If my preamble shows that I have understood correctly the basic premise, I have one or two questions that I am trying to work through. So: 1: Is there a one to one...

Hello. I am confused with this matter that how should we write the transformation matrix for an expanding space. consider a spacetime that is expading with a constant rate of a. now normally we scale the coordinates for expansion which makes the transformation matrix like this: \begin{pmatrix}...

Everyone, this post is going on multiple forums/subreddits so I can get diverse feedback. Pardon the spam if you see it elsewhere: I am retiring from the military in three years from a non-technical specialty. I have a bachelors in management. I will be 45 when I depart. I will have a security...

its summer where i live and the ceiling space gets extremely hot, much hotter than ambient outdoor. under a shade outdoor, the air temp beneath shade will be colder than air temp in sunlight. yet in a space with no air flow, the temp is always hotter from my experience. why is this? this isn't...

The interesting thing about scifi space travel is that it remains hard even with scifi tech, so long you allow propellant and gravity limits to still exist. In a way it is kind of a good thing, only in that it prevents widespread easy RKV starship use. My question is how long would travel take...

Sigh ... Best statement "... although aliens may not be made up of carbon and nitrogen like humans "it's possible they're here right now and we simply can't see them". " https://www.bbc.com/news/uk-51003374

In physics, the concept of absolute time and absolute space are hypothetical concepts closely tied to the thought of Newton. Absolute, true and mathematical time of itself, and from its own nature flows equally without regard to anything external. There is another term duration measures...

The Boeing Starliner just launched into a pre-sunrise cloudless sky. It was fun to see the black smoke trail change to white as it lifted into the sunlight (pic 1). It was not as spectacular as the post-sunset launch from California a few months ago. The trajectory became more horizontal...

Space evidently is expanding, so we say that the very fabric of space time is expanding uniformly in all directions, so two questions 1)originally this expansion was driven by the energy content within the universe aka the dense hot matter , versus nowdays the acceleration is picking up speed...

I'm writing an SF novel with FTL travel. In my story, there are different motion regimes, including superluminal, based on this https://www.researchgate.net/publication/333614143_A_GENERAL_LOCAL_CAUSALITY_PRINCIPLE_OF_SPACE-TIME_A_PREPRINT I found. My story: in our (c1) regime, whatever...

Hypothetical scenario and I'm trying to understand the velocity of the air as it tries to equalize with a large vacuum. I presume this model isn't very much different from an initial loss of 1 atmosphere pressure in space via some puncture. I'm mainly concerned with the immediate wind speeds and...

Which do you think is superior, given similar tech for both opponents? If one opponent nation went all in for mass produced cheap space vehicles, would that not beat one that produced a limited number of heavily armed spacecraft ? Scenario is a space battle only, from deep interplanetary...

With voyager 2 now going to interstella space what have we learned?

What feature of the equations of classical physics show that space and time are fundamental and how would the equations differ if space and time were not fundamental but emergent? I heard all of this from a previous talk and I would appreciate any help and any further reading recommendations.

X=e+or-kx (1) <X(x)|Φ(x)>=∫-∞∞X*(x)Φ(x)dx (2) where Φ(x) satisfies the following. ∫-∞∞|Φ(x)|2(1+|x|)ndx is finte if n=0, 1, 2,...

I understand that there are many forums and topics written on the fact that space is expanding. But I've looked and looked, and couldn't find an answer to my specific question. How do we know space is expanding, rather than galaxies just regularly moving apart? How do we know galaxies are...

hello, please can you help me in this problem

If I understand this question correctly, I am supposed to prove an integrate from negative infinity to infinity ∫x|∅(x)|2(1+|x|)ndx is finite. Sorry, but I have no idea.

I have a bit of a love affair with rocks that come from outer space. To hold a piece of rock that has zoomed through space for zillions of years before finally crashing to Earth still gives me that WOW factor. I have around 55 samples in my collection from many different falls around the world...

I'm pondering the behavior and persistence of rocket exhaust plume molecules far above the atmosphere. For example, the plume from an apogee circularization thrust from GTO (Geosynchronous Transfer Orbit) to GEO (Geosynchronous orbit). CO₂ and H₂O are among the molecular species emitted by a...

. We have that energy in a infinitesimal Spherical layer with number of mols dn is: dU=Cv.T.dn (1) But by the ideal gas law: PV=nRT (2) Differentiation gives: PdV+VdP=RTdn (3) (3) in (1) and using CV=3R/2 (monoatomic) gives: dU=3/2.(PdV+VdP) (4) Integration of (4) over the whole gas will...

In quantum mechanics, the Eigenfunction resulting from the Hamiltonian of a free particle in 1D system is $$ \phi = \frac{e^{ikx} }{\sqrt{2\pi} } $$ We know that a function $$ f(x) $$ belongs to Hilbert space if it satisfies $$ \int_{-\infty}^{+\infty} |f(x)|^2 dx < \infty $$ But since the...

Can I sum up the potential due to all positive line charges and all negative line charges separately, with the boundary condition being at the edge of my unit cell, the potential should be the same and inside the metal there is a contant potential?

n = 11000 because n = N/V and V = 1m^3. Using P = nRT/V I get that P = 7.32x10^6 Pa. considering that the gas is in a high vacuum, this value seems far too high to be true. Please help?

I= 524kg * 6m^2 = 18.86E3kg*m^2 KE=(1/2) (18.86E3kg*m^2) (0.16 rad/s )^2= 241.5 J torque= 0.25* 57N* (6m)=85.5 N*m

Summary: (1) Would it be possible (relatively speaking) for a spaceship to "sit" stationary in space, i.e., not in orbit around a planet; and (2) if possible, how long would it take a planet, viewable from the spaceship's window (humor me) to pass through your field of vision? Part One I'm...

I'm a bit lost at how to exactly start this exercise... As far as I understand we need to first determine ##d\tau_E## and ##d\tau_S##. First question: Since we can neglect the Earth's movement, can I also neglect the movement of the satellite with respect to the far away observer? If so, I...

Nations prohibit the detonation of nukes in space, but I don’t know there is a better way to use these weapons of mass destruction, than propelling a probe on a interstellar travel at relativistic speeds in the near future. Also, the origin Orion, where all the nukes are carried onboard, will...

KSP was one of the most famous science games as it simulates a complete space program, as well as physics such as aerodynamics and orbital mechanics. Such science focused games are rare, and something favourable amongst nerds. To make it even better, it is easy to modify the game and add almost...

1.) Ion drive 2.) Black hole starship 3.) Fusion Rocket 4.) Fission sail https://en.m.wikipedia.org/wiki/Fission_... 5.) Halo drive https://arxiv.org/abs/1903.03423 6.) Horizon drive https://www.tsijournals.com/articles/pro... 7.) Pitch drive, Diametric drive, Disjunction drive...

Mass causes space to change shape, and that's what we see as gravity. But does space move when it changes shape? If yes, relative to what?

As per source # 1 ( link below), when treating polynomials as vectors, we use their coefficients as vector elements, similar to what we do when we create matrices to represent simultaneous equations. However, what I noticed in Source #2 was that, when functions are represented as vectors, the...

A central feature of classical GR that it is background independent and operates via a curvature in space-time. As I understand it, this is not true of the other Standard Model forces which are consistent with special relativity and operate in Minkowski space, in which forces are transmitted via...

When I ask Google how to expand space, I get suggestions on removing junk or questions on what it is expanding in to. I am going to try asking here and I know I must phrase the issue properly. It is agreed that many scientists claim that space expanded around the time the universe began. I...

I am assuming the set ##V## will have elements like the ones shown below. ## v_{1} = (200, 700, 2) ## ## v_{2} = (250, 800, 3) ## ... 1. What will be the vector space in this situation? 2. Would a subspace mean a subset of V with three or more bathrooms?

Hi, in the lecture notes my professor gave us, it is stated that, due to Kramers theorem, the energy in a band must satisfy this condition: $$E(-k) = E(k)$$ But, judging from actual pictures of band structures I don't find this condition to be true. Here's a (random) picture I guess it looks...

Its velocity, Vp, is towards some other part of the universe, It rotates in the same plane as its direction of travel. The linear velocity of an object on the surface of the planet relative to the centre is Vr. That means the object's total linear velocity is Vp+Vr when it's at one point in its...

So there's two spaceships in deep space. at rest with respect to each other. Then one of them shoots off at some huge speed and everyone feels it. Then they shut the engines off suddenly. No one is going to suddenly lurch forward, they will at the instant the engines are shut off effectively be...

Is it possible to build a skyscraper that's so tall that it enters the ozone layer? I was imagining such a tower where customers could go to the top in elevators and view the Milky Way in bed with a glass roof in their luxury apartments :) Obviously not just a tower without supports. Maybe with...

If one shows that ##U\cap V=\{\textbf{0}\}##, which is easily shown, would that also imply ##\mathbf{R}^3=U \bigoplus V##? Or does one need to show that ##\mathbf{R}^3=U+V##? If yes, how? By defining say ##x_1'=x_1+t,x_2'=x_2+t,x_3'=x_3+2t## and hence any ##\textbf{x}=(x_1',x_2',x_3') \in...

Do we need more force to push a body with 100kg mass than of 1kg mass in space(in vacuum)?

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I read in my textbook Calculus on Manifolds by Spivak that a set ##A\subset \mathbb{R}^n## is bounded iff there is a closed n-rectangle ##D## such that ##A\subset D##. It should be plain that if I wanted to define unboundedness, I should just say something along the lines of: "A set ##A\subset...