Dark Energy: Mass, Distance & Gravity Relationships

  • Context: Graduate 
  • Thread starter Thread starter chris2112
  • Start date Start date
  • Tags Tags
    Dark energy Energy
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 reply · 2K views
chris2112
Messages
20
Reaction score
0
Is there a function of mass that tells us the distance that two objects are no longer gravitationally bound and start moving away from each other due to dark energy? Is mass arbitrary at a certain distance? To make my question broader, can anyone show me equations describing relationships between the forces of gravity and dark energy on mass?
 
Last edited:
Astronomy news on Phys.org
Following http://arxiv.org/abs/astro-ph/0302506, we can define the rough length scale at which objects begin to disspiate due to dark energy by:
[tex]-\frac{4\pi}{3}\left(\rho + 3P\right)R^3 \sim M[/tex]

Taking a normal value for [tex]\Lambda[/tex] and assuming an equation of state of -1, such that [tex]\rho = - P[/tex], I get

For a mass of [tex]1 M_{\odot}[/tex] , ~100 pc (Solar system),
For a mass of [tex]10^{10} M_{\odot}[/tex], ~ 200 kPc (Galaxy),
For a mass of [tex]10^{13} M_{\odot}[/tex], ~ 2MPc (Cluster).

This suggests that all three systems are gravitationally bound and will never be disrupted.