Questions tagged [spacetime-dimensions]

Concerning dimensions of space and time, whether our 3-space + 1-time or other dimensions.

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35
votes
9answers
7k views

What does it actually mean to have two time dimensions?

The trivial answer is that it just means "you have two dimensions with inverted sign in your spacetime metric". But the perceptual result of that kind of choice doesn't actually look qualitatively ...
48
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11answers
19k views

Would a 4-dimensional being be able to see inside other people?

I have a tribe that is completely isolated from the outside world and there is a shaman that can see in 4 dimensions. He can identify disease before it manifests and is hailed as a god. This 4th ...
7
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1answer
299 views

Schwarzschild Metric in a universe with the same space time metric as that described in the orthogonal series, but with massive gravitons?

The universe described in the orthogonal series http://www.gregegan.net/ORTHOGONAL/00/PM.html is one, in which the minus sign in the space time interval is replaced with a plus sign. So this universe ...
29
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5answers
2k views

How to test a time machine?

Eureka! I have a time machine in my garage and it works. I put an apple in it, close the door, set the timer, open the door to an empty machine, wait five minutes and the apple reappears. (Still ...
10
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6answers
710 views

Flipped over through fourth dimension. When do I start to notice biological problems?

In the middle of the night, while J. Random Human is sleeping, A. Hypersphere picks him hyper-up extremely carefully (so that none of his matter falls out in a direction he doesn't have), flips him ...
13
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10answers
3k views

How could two alternate realities “blend” at a single point in space time?

From: https://en.wikipedia.org/wiki/Multiverse The multiverse (or meta-universe) is a hypothetical set of various possible universes including the universe which we live in. Together, these ...
3
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2answers
104 views

How would wormholes and teleportation affect the passage of time?

Time is not a constant, Albert Einstein proved that much. Time dilation is a difference in the elapsed time measured by two clocks, either due to them having a velocity relative to each other, or by ...
7
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2answers
131 views

Formula for send and response times of messages at fraction of light speed?

I have a ship that begins the equation traveling at 50 percent the speed of light, but decelerating constantly to finally land on a certain planet (towards which it is moving the entire time). It ...
2
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1answer
162 views

Message sent to a ship traveling away at 37.5% light speed? [closed]

I have a ship traveling away from Earth at around 37.5 percent of light speed. How long will a message take to reach first Earth, and then a response to reach the ship, both from Earth perspective and ...
3
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7answers
356 views

What would a two-dimensional world look like?

As we know our real world is (if we ignore extreme physical theories) three-dimensional. I wonder what a two-dimensional world would look like and if live would be possible. In my opinion many ...
4
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6answers
232 views

Technology to see an invisible being

I have a world where there are two types of beings. One type, let's call them X, exist in our "dimension," and the other, let's call them Y, exist in another "phase" or dimension. Only 10% of X ...
1
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1answer
162 views

What are some modern policies that can be applied to or improve 17th-century European society? [closed]

Supposedly, a relatively smart + educated young woman from modern society is transmigrated into a body of a woman living in a country that is similar to 17th-century Europe. Monarchy and nobility ...
2
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5answers
339 views

What would the experience be like for a human transported to 4 dimensions?

Our universe has 3 global spatial dimensions - that much I know. I am almost sure, based on an incredibly shoddy knowledge of physics, that there couldn't possibly be a 4th spatial dimension that we ...
43
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1answer
5k views

What would the periodic table of a 4-Dimensional universe look like?

In this question, I asked about a universe with (amongst other things) 4 large spatial dimensions. In 3 dimensions, we have the familiar periodic table with its familiar arrangement of atoms in the S,...
6
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4answers
1k views

Consequences of a two-dimensional universe on cells and life

Suppose you have a 2+1 dimensional universe where the physics of that universe (we'll assume that the physics causes something similar to chemistry and that there is no gravity, but there is special ...
11
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4answers
622 views

Chemistry in two spatial dimensions?

I know that someone has asked how chemistry would be in four dimensions but I was wondering what would chemistry be like in two dimensions? From what I understand, in two dimensions, particles, ...
8
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5answers
320 views

Sanity check: 4D bio-wheels

In our 3D world, it is basically impossible to evolve living wheels, or helicopter rotors, or anything similar because free rotation of an axle dictates that there is no fixed connection to the body ...
12
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2answers
592 views

Body plan of a 4D human-analog?

I am attempting to design aliens that live in a universe with a 4+1 space-time--i.e., a universe with four orthogonal spatial dimensions, rather than three, in addition to a fifth time dimension. In ...
7
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4answers
492 views

Aliens in a 4D universe try to explore our 3D spacetime fabric: How can they do it?

They do not necessarily meet humans and try to interact with them. This question is more about the technical possibility/impossibility of 4D aliens being able to "analyze" the inner structure of our ...
11
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3answers
436 views

What goes in, must come out - limitations of temporal displacement

I am plotting out a sci-fi setting, and trying to figure out the consequences of a non-conventional form of time travel. In the story, time travel has been achieved by means of temporal displacement....
4
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3answers
526 views

Can mass be shunted off into hyperspace, but the matter remains?

My question is this: can excess mass be bled off into hyperspace (the large and compact extra dimensions, not the Star Wars-esque swirling vortex), yet the matter remains in our universe? Is mass too ...
8
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4answers
326 views

How can a species of natural time-travelers have a meaningful society?

Consider a fantasy species of "natural" time travelers. To define some specifics: Relevant Rules While it is not effortless, this species can move against the "arrow of time" much as a human can ...
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3answers
191 views

Is it possible for two dimensions to exist on one planet? [closed]

I'm writing a fantasy comics and I am stuck on a particular idea. Imagine if Hell existed on our planet. Like hell is here, we simply cannot see it, because there is an invisible barrier between the ...
3
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0answers
170 views

What would the periodic table look like in 2 dimensions? [closed]

I've read this question What would the periodic table of a 4-Dimensional universe look like?, and I think it answers part of my question about how atomic physics would work, but I'm not sure. Would a ...
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1answer
155 views

Time travel only possible when we go behond light's speed [closed]

Friends here are my views on Time Travel: I think with every past second the light rays of that particular second travel in a different dimension & therefore the light rays of next second travels ...
4
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3answers
210 views

How do one teach thermodynamics to Higher dimensional beings?

Suppose an entity from a higher dimensions who can experience time flowing both forward and backward wants to understand our world and how far humanity have advanced in tech and science, is it ...
10
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2answers
597 views

How to feed parity transformed John Doe?

We do not know how exactly it happened, but poor John Doe made a space-time trip along a three dimensional analog of a Möbius strip (a Klein bottle). He is now back on Earth, but he is now the mirror ...
2
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0answers
124 views

What would conditions be like at the hyperbolic horizon? [closed]

I am imagining a fantasy world where the horizon is a real place. If you travel to where the dome of the sky appears to meet the ground, you can even find intrepid human settlements on the edge of - ...
15
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1answer
2k views

Aritifical Gravity through Rotating wheel generalisation in a spatial 4th dimension

I'm taking the example of a rotating wheel space station, in which artificial gravity is created through rotation due to the inertia inside. The idea in the 3D environment is that the wheel (2D) is ...
5
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1answer
396 views

Using Microscopic Dimensions to Hide Objects

Idea prompted by Brian Greene's The Elegant Universe: String theory postulates microscopic dimensions in space. Could you conceal an object by rotating it into one of the microscopic dimensions and ...
47
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17answers
8k views

What if we lived near a boundary of the universe?

This answer and its follow-up discussion with the OP made me think, and boil it down to the essentials: We live in a universe that’s either infinite in spacial extent or unbounded, and wrap-around ...
7
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4answers
1k views

Would an explosion or energy discharge permeate to other spatial dimensions?

Let's assume there are more than 3 spatial dimension, for example 4 (the 4th not beeing time, but spatial) Would a common energy discharge, explosion etc. affect the 4th dimension? I am not sure if ...
4
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2answers
274 views

Astronomy in a universe with two “straight” dimensions plus a highly curved dimension

So for lack of a better term (I'm sure there is a better term) imagine a universe without curvature as being like a sheet of paper. You have left, right, forwards, backwards, up, and down. Now take ...
3
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4answers
434 views

Using an Alcubierre Drive to travel through the fourth dimension

Say there is a fourth spatial dimension ( let's call it the q axis as in x,y,z axis ) and that humans are still 3D beings. Could we use an Alcubierre drive to travel through the fourth dimension? As ...
5
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7answers
629 views

Uses for “Pocket Universe” backwards Time Travel? [closed]

As it turns out, Time Travel is possible! It's just not as useful as we thought it would be, that's all. You can only go back in time, and not really. Whenever anyone goes back in time, a pocket ...
8
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2answers
502 views

What would a area of slower/faster time look like?

I've been thinking about doing something involving bubbles of stopped (already answered here), slowed down or sped up time. What would that look like for different speeds? Is there any way of ...
15
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5answers
2k views

Physical laws for a matter-filled universe

The Setting: I have an idea for a universe that, in an inversion to our own, is filled for the most part with matter in solid, liquid, gaseous or plasma form, while vacuum and degenerate matter is ...
-1
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1answer
295 views

Spherical vs Circular(planar) wormholes; possibility? [closed]

I know that 'they' are theoretical and hypothetical, but please justify deep down to your understanding and I'll try to grab-up as much Origin of Problem: Thanks to the fantasy and fiction, there ...
88
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31answers
17k views

My time machine needs to know when it is

I've built a time machine and it works in unmanned testing... sorta. I tell it to go into the past, it disappears, and then comes back to the present. The problem is that it isn't terribly accurate. I ...
7
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3answers
413 views

Is there a problem with interpreting dark matter as hidden dimensions?

Is there any solid, scientific counterargument against the hypothetical explanation that attributes dark matter as matter in hidden planes of existence? I am trying to construct a world in which ...
4
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1answer
107 views

Looking for an Explanation of Time Dilation I can program into a CLI calculator [closed]

Thanks but I can code it, not what I am looking for I am just looking for an explanation or equation that is clear and not too heavy in parlance for how these trips would be to people of Earth and ...
15
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6answers
2k views

I'd like to set up a UI for a 2D square to access the internet— any ideas? [closed]

I have a friend who is a square (i.e. he lives in a 2 dimensional plane on the surface of a table that I keep in my bedroom). He has decent hearing and understands English, but I'm getting tired of ...
10
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1answer
146 views

Discovery of space-time distortion via post-apocalyptic cartography?

So I have been working on a world where space has been "cracked" by some mysterious disaster which plunged the world into chaos. It is not immediately apparent - i.e. no giant glowing holes in the ...
4
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1answer
159 views

No time dilation, what would it imply? [closed]

In a universe where space and time are two independent things. Where time is universal. Where time "passes at the same speed" in any point in space, and dilation never occurs, regardless of mass and ...
3
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2answers
504 views

would the shadow of a 4th dimensional object be physical to a 3 dimensional being? [closed]

If there was a 3 dimensional plane existing within a 4d space and something forth dimensional casts its shadow into this 3d plane would it be physical to 3d beings on that plane? Now theoretically a ...
3
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2answers
401 views

What would a world be like with cross dimensional contact? [closed]

A universe of 10 dimensions I'm trying to build a universe with interactions between beings from different dimensions. Only dimensions 3 and up would be capable of spawning any sort of life. The most ...
6
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2answers
195 views

Viability of options for super tall tower

I've been reading through other posts about such megastructures and they're getting me part of the way to my destination. Wanted to see about a few specific options my imagination has latched onto. ...
1
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0answers
86 views

Concerning Brane cosmology [closed]

EDIT: If an actor or object in a higher dimensional space with less mass than say, my car, attached itself to the car through our dimension's membrane, would it be able to move the car or hold it in ...
0
votes
1answer
149 views

What happen to gravity if time is suddenly running backward? [closed]

From my naive understanding of Einstein theory of relativity: gravity is not a force but only a consequence of inertia in a world where mass deforms the space-time. Without time, no gravity is ...
1
vote
3answers
262 views

How everything will act in a world of two time dimensions? [closed]

As far as we know , we live in a universe with only a single dimension of time, we know that some events happens BEFORE or AFTER other events , we know that some events happens slower or faster then ...