Gravity and the expanding universe

In summary, the conversation discusses two main topics: theories of gravity and the expansion of the universe. The speaker suggests exploring Wikipedia for information on the various theories of gravitation, including Newtonian, Einstein's general relativity, and loop quantum gravity. They also point out that science may provide explanations for how gravity works, but not why it exists. The conversation ends with the speaker questioning why the universe is expanding instead of shrinking.
  • #1
xaviat
1
0
OK, a couple of things.

1. I know there are a few theories of "why" gravity exists with gravitons and entropy, etc. But know one really knows.

Does anyone have any good websites where all theories are discussed in one section? I am having to go all over the place to find information.

And 2. This is just me wondering, If all object produce gravity, and the larger they are the more gravity they produce, then why is the universe expanding rather than shrinking? Doesnt it make more sense that all solid obejcts atract each other. I understan that orbits cause objects to travel past each other, but eventually won't everything just collapse back on itself?


Any insight appreciated it.

Cheers,
X
 
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  • #2
your best bet is to explore wikipedia to read about the various theories.

Just keep in mind science can't answer why. It can provide a theory that models the phenomenon remarkably well from which we imagine we understand how it works but not the why of it.

Theories of Gravitation:
- Newtonian
- einstein's general relativity
- loop quantum gravity

http://en.wikipedia.org/wiki/Alternatives_to_general_relativity
 

What is gravity?

Gravity is a fundamental force of nature that causes objects with mass to attract each other. It is responsible for keeping the planets in orbit around the sun and the moon around the Earth.

How does gravity affect the expansion of the universe?

Gravity plays a crucial role in the expansion of the universe. It is responsible for the formation of large-scale structures such as galaxies and galaxy clusters. As these structures have a strong gravitational pull, they can slow down the expansion of the universe.

What is dark matter and how does it relate to gravity and the expanding universe?

Dark matter is a hypothetical type of matter that does not interact with light and other forms of electromagnetic radiation. It is believed to make up about 85% of the universe's mass and plays a significant role in the expansion of the universe through its gravitational effects.

How does the theory of general relativity explain gravity and the expanding universe?

The theory of general relativity, proposed by Albert Einstein, explains gravity as the curvature of space and time caused by the presence of mass and energy. This theory also accounts for the expansion of the universe through the concept of the cosmological constant, which represents the energy density of the vacuum of space.

What evidence supports the theory of gravity and the expanding universe?

There is a vast amount of evidence that supports the theory of gravity and the expanding universe, including the observation of the redshift of distant galaxies, the cosmic microwave background radiation, and the formation and movement of large-scale structures such as galaxy clusters. Additionally, the predictions made by the theory of general relativity have been consistently confirmed through various experiments and observations.

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