Difference between particle horizon and cosmological event horizon?

AI Thread Summary
The Particle Horizon defines the observable limit of the universe, indicating what can be seen today, while the Cosmological Event Horizon represents the ultimate limit of what may ever be observed, regardless of time. The Event Horizon is influenced by the universe's geometry and expansion history. Discussions highlight the confusion surrounding these concepts, particularly regarding the observable universe and the surface of last scattering. Some suggest that super-hubble fluctuations could leave imprints on the Cosmic Microwave Background, though this remains debatable. Understanding these horizons is crucial for grasping the limits of cosmic observation.
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What is the difference between particle horizon and cosmological event horizon?
 
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touqra said:
What is the difference between particle horizon and cosmological event horizon?
The Particle Horizon is the limit of what we can see today, (it takes longer than the present age of the universe for light to reach us from beyond the PH), the Event Horizon is the limit of what we may ever see, even if we wait for ever. (the EH is determined by the geometry and expansion history of the universe)

Garth
 
Garth said:
the Event Horizon is the limit of what we may ever see, even if we wait for ever. (the EH is determined by the geometry and expansion history of the universe)

Garth

Could you elaborate further on the Cosmological EH?
 
The horizons thing creates more confusion than clarity, IMO. In our [observable] universe, the surface of last scattering is the observational limit - again IMO. Super-hubble fluctuations may have left trace imprints on the CMB - albeit that is debatable - but in a temporally bounded BB universe, it is impossible to observe entities that [may or may not have] existed prior to recombination.
 

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