Gravity and the expanding universe

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SUMMARY

The discussion centers on the nature of gravity and the expansion of the universe, highlighting the lack of consensus on the fundamental reasons for gravity's existence. Participants mention various theories of gravitation, including Newtonian gravity, Einstein's general relativity, and loop quantum gravity. The conversation raises questions about why the universe is expanding despite the gravitational attraction of massive objects. A suggestion is made to utilize Wikipedia as a comprehensive resource for exploring these theories.

PREREQUISITES
  • Understanding of Newtonian gravity
  • Familiarity with Einstein's general relativity
  • Knowledge of loop quantum gravity concepts
  • Basic grasp of cosmological principles
NEXT STEPS
  • Research the implications of Einstein's general relativity on cosmic expansion
  • Explore the concept of dark energy and its role in the universe's expansion
  • Study the differences between classical and quantum theories of gravity
  • Investigate current theories and models of the universe's fate
USEFUL FOR

Astronomers, physicists, and students of cosmology who are interested in the fundamental nature of gravity and the dynamics of the expanding universe.

xaviat
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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
 
Space news on Phys.org
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
 

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