The Cosmic Dance of Galaxies: Redshift and Luminosity Over Time

Have you ever wondered if any galaxy has reached a point where its redshift has increased over time or its luminosity has decreased, as indicated by the data we have on a 100-year-old redshift survey? This is a fascinating question, especially when we consider the Standard Model of Cosmology (SCM-LCDM) and the implications of cosmic expansion.

Standard Model of Cosmology and Cosmic Expansion

According to the SCM-LCDM, our universe has undergone significant expansion since the big bang. This expansion is a key component of the model, indicating that galaxies are moving away from each other at increasing speeds. In the context of this theory, a galaxy that is farther away will appear to have a stronger redshift, as its light has been stretched to longer wavelengths due to the expansion of space. Conversely, closer galaxies might appear more stable in their redshift and luminosity, providing a baseline for comparison.

Contrasting Cosmic Expansion with the Smithsonian Institute of Research and Analysis (SPIRAL)

The SPIRAL model, proposed by the Smithsonian Institute of Research and Analysis (SPIRAL), offers an alternative perspective to cosmic expansion. According to SPIRAL, the absence of ongoing cosmic expansion from the point of cosmic inflation would result in a very different universe. In a universe without cosmic expansion, the light from distant objects should appear regular as it would have never been stretched by the expansion of space.

However, in our actual universe, we observe a hierarchy of light from stars and galaxies that have been subjected to cosmic expansion. This is evident in the steady increase in redshift as we observe objects that are farther from us. For example, a star or galaxy that is 1 light-year (LY) more distant from us would be subjected to a slight increase in redshift. If we were to consider the minimum distance to such objects, it would be approximately 5779 light years, where the effects of cosmic expansion would be more pronounced.

Stability of Cosmic Radio Sources (CR)

While the effects of cosmic expansion can be observed over vast distances, some objects, like Cosmic Radio Sources (CR), offer a different picture. According to SPIRAL, CR from particular stellar objects should remain more stable over time, especially if they are not subjected to continuous cosmic expansion. This stability can be seen in the nearest CR 'ed' (cosmologically redshifted) stellar objects, which might be around 1 million light years (Mly) away. These objects' light has been affected by cosmic expansion, but the effects can still be detected at closer distances, providing a unique context for studying the universe's history.

Implications for the Most Distant Stellar Objects

Considering the vast distances in our universe, the most distant stellar objects or galaxies are thought to be around 2 billion light years (bl) from us. The sphere of the visible universe approximates the entire universe, so we can infer that in 2 billion years, the nearest object whose light reaches us now, subjected to cosmic redshift (CR), will still be within this sphere. Beyond this radius of 2 billion years, the universe as we know it does not allow for further cosmic redshift of distant starlight.

Resolution of the Question

Therefore, to answer the original question: any galaxy that is currently showing a higher redshift or a decrease in luminosity would suggest that it is getting farther away, subject to the ongoing expansion of the universe. Conversely, if we observe stable or decreasing redshift at closer distances, it might indicate ongoing cosmic expansion, as predicted by the SCM-LCDM. If the universe were NOT expanding, or if it had stopped expanding beyond a certain distance, we would not see the redshift-distance relationship we observe.

This is in stark contrast to the predictions of the SPIRAL model, where the visibility of cosmic expansion effects should be more consistent and stable at all distances, given the absence of ongoing expansion.

For further reading and resources on this topic, refer to the Comparison between SPIRAL and Hubble's Observations.

Understanding the cosmological redshift (CR) and its implications is crucial for comprehending the vastness and complexity of our universe. Through continued research and observation, we can unravel the secrets of cosmic expansion and the dynamics of galaxies.