Space expansion on smaller scales

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SUMMARY

The discussion centers on the effects of space expansion on smaller scales, particularly within galaxies and between planets. It is established that while space is expanding, the gravitational forces within galaxies, such as the Milky Way, counteract this expansion, preventing galaxies from being pulled apart. The expansion of space primarily affects vast intergalactic distances, with adjacent galaxies remaining largely unaffected due to their gravitational binding. The concept of Hubble expansion is highlighted as a key reference for understanding these dynamics.

PREREQUISITES
  • Understanding of Hubble's Law and redshift phenomena
  • Basic knowledge of gravitational forces in astrophysics
  • Familiarity with the concept of cosmic expansion
  • Awareness of galaxy dynamics and interactions
NEXT STEPS
  • Research Hubble expansion and its implications on cosmic scales
  • Study gravitational binding and its effects on galaxy formation
  • Explore the concept of cosmic inflation and its role in the universe's expansion
  • Investigate the future collision between the Milky Way and Andromeda galaxies
USEFUL FOR

Astronomers, astrophysicists, and students of cosmology seeking to understand the implications of cosmic expansion on galactic structures and interactions.

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Space is expanding. This is evident from the redshift of distant objects.

My question is what effect does it have on smaller scales? Since the expansion of space carries objects along with it (necessary for the objects to be farther) wouldn't the expansion within galaxies slowly pull them apart? wouldn't the expansion on planets exert a minute outward pressure? on smaller objects?

Of course due to the small distances involved (since the stretching of space is cumulative over distance i.e. that unit of length expands x, as does the next one) and the large timescales required, these effects would be miniscule, but they would be present, right?

Or is the fact that the galaxies are moving with the expansion not due to causation but due to a root common cause: i.e. space is expanding, but it does not carry objects with it. The reason galaxies move along with the expanding space is only due to their initial outward momentum from the big bang.

Which (if either) seems to be the correct model as to our current understanding? I'm a little bit confused...
 
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You should do a search..this has been discussed many,many times. Or search Hubble expansion...here or Wikipedia.

The gravity holding galaxies together prevents expansion within galaxies...the universe expands only over vast intergalatic distances...adjacent galaxies are essentially not affected...for example, our Milky Way galaxy is going to collide with our nearest neighbor galaxy, the Andromeda galaxy
 

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