# Question about gravity on the large scale.

• cragar
In summary, the conversation discusses Olbers's paradox and its potential application to gravity. The speakers assume an infinite amount of evenly distributed planets with a constant mass and discuss how the gravitational field would cancel out in all directions. They also compare this concept to Gauss's law and question how to determine the center and balance the infinities. The conversation then shifts to the idea that we are at the center of our observable universe and how space appears the same in all directions. The speakers mention that measuring the temperature can indicate movement relative to the cosmic microwave background.
cragar
I was thinking about olbers paradox and how I could apply it to gravity.
We assume that their are an infinite amount of planets and that they are all about
the same mass or we will just pick a minimum mass. And we assume they are evenly distributed. So the gravitational field falls off as 1/r^2 but the amount of planets grows
as r^2. So If there were an infinite amount of planets or stars or whatever, we would experience an infinite pull, but this would be in all directions so it might cancel.
i guess this is similar to gauss's law. But how would we know where the center is or how would we balance these infinities?

We are all in the center of our observable universe with a finite age - and as space looks nearly the same in all directions (if you are at rest with respect to the CMB), you don't get a significant attraction. There are some attracting things if you have a closer look.

How would you know you at rest compared to CMB
Would you tell by measuring the frequency.

You measure the temperature (which is related to the total intensity) and look for a dipole moment: If the CMB is hotter in direction X and colder at the opposite side, you are moving towards X (relative to the CMB).

Firstly, it is important to note that Olbers' paradox is a concept related to the observable universe and the distribution of light, not gravity. However, your idea of applying it to gravity is interesting and can be explored further.

In order to understand the effects of gravity on a large scale, we must first consider the size and distribution of the objects that are exerting this force. In your example, assuming an infinite number of evenly distributed planets with similar masses, we can see that the gravitational pull would indeed cancel out in all directions. This is because the gravitational force between two objects is inversely proportional to the square of the distance between them. As the number of objects increases, the distance between them also increases, resulting in a decrease in the overall gravitational force.

However, it is important to note that this assumption of an infinite and evenly distributed universe is not reflective of our current understanding of the universe. The universe is constantly expanding and the distribution of matter is not uniform. Therefore, the effects of gravity on a large scale are more complex and cannot be simplified to a simple cancellation of forces.

As for determining the center of this infinite universe, it is not possible as it is a theoretical concept. In reality, the center of the universe is constantly changing as the universe expands. Similarly, balancing these infinities is not feasible as they exist only in theoretical scenarios.

In conclusion, while your idea of applying Olbers' paradox to gravity is intriguing, it is important to consider the limitations and complexities of our current understanding of the universe. Gravity on a large scale is a complex phenomenon that cannot be fully explained by simple assumptions and requires a deeper understanding of the distribution and behavior of matter in the universe.

## 1. What is gravity on the large scale?

Gravity on the large scale refers to the gravitational force between massive objects, such as planets, stars, and galaxies. It is a fundamental force of nature that causes objects to be attracted to one another.

## 2. How does gravity affect the universe?

Gravity plays a crucial role in shaping the structure and evolution of the universe. It causes matter to clump together, forming galaxies, galaxy clusters, and superclusters. It also influences the motion and behavior of celestial bodies, such as planets, stars, and black holes.

## 3. Does gravity work differently on a large scale compared to a small scale?

Although the basic principles of gravity remain the same on both large and small scales, there are some differences in how it behaves. On a large scale, gravity is mainly influenced by the distribution of matter, while on a small scale, other forces, such as electromagnetism, play a more significant role.

## 4. Can gravity be observed on a large scale?

Yes, gravity on a large scale can be observed through various phenomena, such as the motion of planets around the sun, the rotation of galaxies, and the bending of light by massive objects. Scientists also use advanced instruments, such as gravitational wave detectors, to study gravity on a large scale.

## 5. How is the study of gravity on the large scale relevant to our daily lives?

While gravity on the large scale may seem abstract and distant from our daily lives, it is essential for understanding the fundamental laws of the universe. It also has practical applications, such as in space exploration, satellite communication, and navigation systems. Understanding gravity on a large scale can also help us predict and prepare for natural disasters, such as earthquakes and tsunamis.

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