Expanding universe and solar system

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SUMMARY

The discussion centers on the effects of cosmic expansion on the solar system, specifically how gravitationally bound objects, such as the Sun and its planets, adapt to this expansion. Participants note that while gravitational forces dominate within the solar system, the changing rate of cosmic expansion, influenced by dark energy, introduces second-degree effects that could alter orbital dynamics over billions of years. The consensus is that the solar system remains largely unaffected by cosmic expansion due to its gravitational binding, which is significantly stronger than the forces at play on cosmological scales.

PREREQUISITES
  • Understanding of gravitational binding and its implications in astrophysics
  • Familiarity with concepts of cosmic expansion and dark energy
  • Knowledge of orbital mechanics within the solar system
  • Basic principles of cosmology, including matter density and critical density
NEXT STEPS
  • Research the effects of dark energy on cosmic structures
  • Study gravitational binding in astrophysical systems
  • Explore the implications of cosmic expansion on galactic dynamics
  • Investigate the role of dark matter in orbital mechanics
USEFUL FOR

Astronomers, astrophysicists, and students of cosmology interested in the interplay between cosmic expansion and gravitationally bound systems.

Dmitry67
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I wonder how the expansion affected the solar system.

Yes, I know that gravitationally bound objects had already "adapted" to the expansion. But it had adapted to the linear expansion - this assumption is valid only when we analyze a limited period of time.

But the rate of the expansion changes, so there are 2nd degree effects which affect the gravitationally bound systems. Even without the dark energy, but the dark energy makes it even more interesting

How big are these effects in the solar system during 4 billion years?
 
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How big are these effects in the solar system during 4 billion years?
I don't have the numbers at hand, but the effect is quite accurately decribed by assuming a constant matter density (the critical) everywhere, with DE counting double negative. If the universe were homogeneous at small scales.
But it isn't, and at our position there should be much dark matter, so orbits are indeed a little bit smaller than predicted by the gravity of baryonic matter (sun and planets and so on) alone.
 
I wonder how the expansion affected the solar system.

By solar system, I assume your mean our own sun and it's orbiting planets...

Our solar system is too tiny to be affected by cosmological expansion...gravitational bounds are just too strong...that effect is observed over intergalatic, cosmological distances...far greater than our even own meager galaxy...
 

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