Life Improbable In 4D+ Universes

  • Context: Graduate 
  • Thread starter Thread starter Gold Barz
  • Start date Start date
  • Tags Tags
    4d Life
Click For Summary

Discussion Overview

The discussion revolves around the implications of higher-dimensional universes (specifically 4D+ and 5D) on the possibility of life, exploring theoretical frameworks from general relativity and speculative science fiction narratives. Participants examine the consequences of dimensionality on gravitational forces, stability of orbits, and the nature of life itself.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Speculative

Main Points Raised

  • Some participants reference the necessity of three dimensions for gravitational waves, suggesting that in lower dimensions, gravity cannot extend outside of mass, leading to a flat spacetime in a vacuum.
  • Others argue that more than three spatial dimensions would disrupt stable orbits for planets and electrons, as gravitational and electric forces would diminish faster than the inverse square law, potentially making life as we know it impossible.
  • A participant mentions Greg Egan's "Diaspora," which explores life in a 5D universe, indicating that while speculative, it presents a scenario where complex life could exist.
  • Some participants question the application of our physical laws to hypothetical higher-dimensional universes, suggesting that different laws could allow for life in such dimensions.
  • One participant proposes that if the 5th dimension is compacted, the issues with stability might be resolved.
  • There is a suggestion that life in a 5D universe might be fundamentally different from life in our 3D/4D experience, possibly beyond human comprehension.
  • Concerns are raised about the observational consequences of higher-dimensional theories, with some participants expressing skepticism about their relevance to our universe.
  • Several participants express fascination with the concept of other dimensional universes, despite acknowledging the challenges in testing such theories.

Areas of Agreement / Disagreement

Participants exhibit a mix of agreement and disagreement. While some accept the notion that life is improbable in 4D+ universes based on current understanding, others challenge this by proposing alternative laws or conditions under which life could exist. The discussion remains unresolved regarding the viability of life in higher dimensions.

Contextual Notes

Participants acknowledge the speculative nature of discussing higher-dimensional universes, noting the lack of empirical testing and the dependence on theoretical frameworks that may not apply universally.

Astronomy news on Phys.org
http://www.theory.caltech.edu/people/patricia/exp3a.html explains that gravitational waves need at least three dimensions (two dimensions to oscillate in, and one to travel in), so in a universe with two spatial dimensions there could be no so gravitational waves, which means that "curvature in 2+1 spacetime dimensions can only exist locally in regions where matter is present. I.e that means that for the example of a single point mass, the spacetime everywhere around the mass will be flat according to the Einstein equations." So, this backs up the statement on the page you linked to that "At least for FEWER than 4 dimensions on the large scale, that is 1 dimension of time, and 2 dimensions of space, it can be shown from general relativity that in such 'universes' the force of gravity does not exist in a vacuum. It cannot extend outside a body and cause other bodies to feel its effects."

As for the statement that more than three dimensions would also make life almost impossible because planets could no longer have stable orbits, this is confirmed by something written by Stephen Hawking on http://www.hawking.org.uk/text/physics/quantum.html :
On the other hand, four or more spatial dimensions would mean that gravitational and electric forces would fall off faster than the inverse square law. In this situation, planets would not have stable orbits around their star, nor electrons have stable orbits around the nucleus of an atom. Thus intelligent life, at least as we know it, could exist only in four dimensions. I very much doubt we will find a non anthropic explanation.
 
Last edited by a moderator:
So...it is improbable for life to arise in 4D+ universes...wow, that sucks majorly
 
In Greg Egan's "Diaspora" he describes in detail a 5 dimensional Star with a “rotational pole” described as a single 2-sphere on the star's 4-dimensional hypersurface that stays fixed in space as the star rotates. in the book very complex life evolved in this polar region: http://gregegan.customer.netspace.net.au/DIASPORA/17/17.html

very speculative [it IS scifi after all- even if well thought-out and reasonable] and quite fascinating!
 
I still don't see why it is impossible, wouldn't a 5D universe have different laws than a 3D universe does? why do we apply our laws to their laws?
 
In a 5D (4D + time) universe Newtonian gravity would be proportional to
r-3 not r-2 and gravitational orbits would be unstable, they would decay. Therefore no galaxy, no star, no planets and no life!

Garth
 
Gold Barz said:
I still don't see why it is impossible, wouldn't a 5D universe have different laws than a 3D universe does? why do we apply our laws to their laws?
They are assuming a universe with the same basic laws but just a different number of spatial dimensions. So yes, if you come up with totally different laws you might be able to imagine a 5D universe where life is possible.
 
If the 5th dimension is assumed compacted, this problem goes away.
 
Gold Barz said:
So...it is improbable for life to arise in 4D+ universes...wow, that sucks majorly

Somehow, I feel a strong inclination to bet that life occassionally arises in 4D anyway.
 
  • #10
"So yes, if you come up with totally different laws you might be able to imagine a 5D universe where life is possible."

Yes I am assuming that the laws would either be tweaked or completely different in a 5D universe

And maybe a 5D's universe life isn't the same as our life a 3D/4D life...I know it sounds stupid but what if it isn't something we can even begin to fathom...like some weird non-organic life
 
  • #11
That assumes higher order dimensional universes exist. It they do, so be it. Do they have observational consequences in this universe? I seriously doubt that. Let's try to reign in our observations to this universe.
 
  • #12
Well...yeah, were assuming, we have no way of testing them or testing the theory that states them...I am just fascinated by other dimensional universes

Chronos did you get my last PM?
 

Similar threads

Alien life, probabilities, and interstellar propagation of human life
  • · Replies 237 ·
8
Replies
237
Views
11K
High School The 3D Universe: A Speck in the 4D Universe
  • · Replies 10 ·
Replies
10
Views
2K
Graduate Prevalence of Earth-size planets orbiting Sun-like stars
  • · Replies 9 ·
Replies
9
Views
4K
Graduate Visualizing 4D Euclidian Space: A Book for Mind-Boggling Effects
  • · Replies 12 ·
Replies
12
Views
3K
What are the different types of knives and swords in a 4D Euclidean universe?
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad Why isn't spacetime considered as true 4D?
  • · Replies 22 ·
Replies
22
Views
5K
Undergrad Is There a Simple Equation for Hubble's Constant and Time in Astronomy?
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Does a truly static "Block Universe" allign with "experience" aspect?
  • · Replies 2 ·
Replies
2
Views
1K
High School Is our 3D universe a shadow of a 4D Universe?
  • · Replies 9 ·
Replies
9
Views
4K
Graduate Could life arise on a brown dwarf?
  • · Replies 2 ·
Replies
2
Views
3K