Spatial dimensions of our universe

In summary, there is a discrepancy between the idea of extended spatial dimensions in string theory and the requirement for three dimensions for life to exist. The difference between small and large scale dimensions is their size, with some being compactified and others being large. The impact on general relativity and gravitation in a universe with more than three dimensions is still being explored through quantum gravity and string theory. String theory proposes that particles are actually strings that exist in the extra dimensions, with 10 spatial and one time dimension being necessary to explain observed particle characteristics.
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cryptist
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On the page 17 of this article by Max Tegmark http://arxiv.org/pdf/gr-qc/9704009v2.pdf, in figure 7, it has been argued that why spatial dimensions other than 3, is not possible for our universe. But in string theory, people are talking about 10, 11 or 26 spatial dimensions (even if these dimensions are thought to be in extremely small scale). Are these two contradicting? If no, why?
 
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  • #3
We are living(!) on a universe that contains life. So our universe has to have 3+1 dimensions then. What is the difference between small scale dimensions and large scale dimensions? For example what would happen to general relativity and gravitation in that case (the universe with more than 3 dimensions)? Again does quantum theory predict these other dimensions?
 
  • #4
What is the difference between small scale dimensions and large scale dimensions?

size.
The small ones appear to be tightly wrapped...'compactified'.
Nobody knows why some are small and others are large.
For example what would happen to general relativity and gravitation in that case (the universe with more than 3 dimensions)?

quantum gravity and string theory are approaches trying to tackle such questions
Again does quantum theory predict these other dimensions?

String theory suggests that 'particles' are strings...one dimensional extensions of point particles...whose characteristics, like energy,charge, spin are determined by the nature of the extra dimensions. Seems so far ten spatial and one time dimension are needed to account for the particle [string] characteristics we observe.
 
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I am familiar with the concept of spatial dimensions and the ongoing research and theories surrounding them. The article by Max Tegmark raises an interesting question about the possibility of there being more than three spatial dimensions in our universe. However, I do not believe that the existence of multiple dimensions in string theory contradicts the argument presented in the article.

In string theory, the existence of additional dimensions is postulated in order to reconcile the fundamental forces of nature and explain the behavior of subatomic particles. These dimensions are thought to exist at a very small scale, beyond our current ability to observe or measure. Therefore, they do not have a significant impact on the macroscopic world that we experience.

On the other hand, the argument presented in the article is based on observations and measurements of our observable universe. It states that the laws of physics and the structure of our universe are most consistent with only three spatial dimensions. This does not exclude the possibility of additional dimensions existing at a smaller scale, but it suggests that they do not play a significant role in the macroscopic world that we can observe and measure.

In summary, the existence of multiple dimensions in string theory does not contradict the argument presented in the article. Rather, it offers a potential explanation for the behavior of subatomic particles and the fundamental forces of nature. Both perspectives can coexist and contribute to our understanding of the universe. Further research and experiments are needed to fully explore the concept of spatial dimensions and their role in the universe.
 

1. What are spatial dimensions?

Spatial dimensions are the physical measurements that describe the position and size of objects in our universe. In our everyday experience, we are familiar with three dimensions: length, width, and height. However, in theoretical physics, there are many theories that suggest the existence of additional spatial dimensions beyond the three we can perceive.

2. How many spatial dimensions does our universe have?

According to current scientific understanding, our universe has three spatial dimensions. This is known as the 3D space, and it is described by the three dimensions of length, width, and height. However, some theories, such as string theory, suggest the existence of extra dimensions that are too small for us to observe directly.

3. How do we know that there are more than three dimensions?

The existence of additional spatial dimensions is not yet proven, but there are several scientific theories and experiments that support the idea. For example, the theory of relativity and quantum mechanics suggest that the universe may have more than three dimensions. Additionally, experiments such as the Large Hadron Collider aim to detect evidence of these extra dimensions by studying the behavior of particles at high energy levels.

4. How do spatial dimensions affect our understanding of the universe?

The number of spatial dimensions in the universe plays a crucial role in our understanding of the laws of physics and the behavior of matter and energy. Different theories propose different numbers of dimensions, and each has implications for how we perceive and interact with the world around us. The existence of extra dimensions could also help explain phenomena that are currently unexplained by our current understanding of physics.

5. Can we travel or access other spatial dimensions?

The possibility of traveling or accessing other spatial dimensions is still a subject of scientific debate and speculation. Some theories suggest that it may be possible through advanced technology or by manipulating space-time. However, there is currently no evidence or technology that can support this idea, and it remains a topic of exploration and research in the scientific community.

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