Relativistic Effects on our Observations of the Universe

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Discussion Overview

The discussion revolves around the implications of relativistic effects on our observations of celestial bodies, particularly focusing on how the finite speed of light affects the information we receive about distant objects in the universe. Participants explore the complexities of modeling the universe when observations are based on data that is temporally delayed due to distance, and they raise questions about the nature of dark matter in this context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that observations of the Sun reflect its state from 8.2 minutes ago due to the finite speed of light, and this applies similarly to more distant objects like Deneb and the M87 galaxy.
  • Another participant agrees that electromagnetic radiation from all objects is time delayed and mentions the added complexity introduced by redshift.
  • A participant expresses a desire to understand the error graph when extrapolating approximate data over large distances and questions the implications of not accounting for newly created matter in models.
  • There is speculation about whether dark matter could be related to newly created matter that is not observable due to time delays, linking this to the motion of gravitons.
  • Another participant challenges the notion of "newly created matter," questioning its effects and visibility in the context of relativistic observations.

Areas of Agreement / Disagreement

Participants generally agree on the time delay of observations due to the speed of light, but there is no consensus on the implications of newly created matter or its relationship to dark matter. The discussion remains unresolved regarding these speculative ideas.

Contextual Notes

Participants express uncertainty about the models used to account for time delays and the potential existence of newly created matter, indicating a need for further clarification on these concepts.

Ralph Spencer
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While observing the Sun, which is 8 light-minutes 12 light-seconds away from us. We (by visible and invisible spectrum of the electromagnetic radiation) observe its state 8.20 minutes ago. Special relativity forbids any information to travel at speeds greater than that of light. This should apply to the information that a mass exists at a particular distance, which is mediated by gravitons. Thus, by all means, the information about Sun that we have is 8.2 minutes old.

If we apply this to Deneb, a star 1.4k light-years away from Earth, its state at a time 1.4k years will we see. Then to the M87 galaxy - 55 ± 1 Mly - its state at a time 55 ± 1M years ago.

How do we model the universe at present (for computations) when we have information that is older further the body away from us? More importantly, how can we compare two objects at different times?
 
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Correct! EM radiation emitted by all objects in the universe are time delayed due to the finite speed of light. The computation process is, as you surmised, complicated - and further complicated by redshift.
 
The computation process is, as you surmised, complicated - and further complicated by redshift.

I would like to have a basic idea of the concept. What would be the error graph when approximate data is extrapolated to such large values?

Maybe I'm thinking far ahead of my current knowledge (which I would rate as beginner), however, if the newly created matter is not accounted in this model, by any chance could our mysterious dark matter be what is created but cannot be observed because of the time delay, which, I could expect to get answer to even in my thread about https://www.physicsforums.com/showthread.php?p=2854997" , which I could relate to motion of the spin-2 and massless gravitons in "certain" conditions.
 
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Ralph Spencer said:
I would like to have a basic idea of the concept. What would be the error graph when approximate data is extrapolated to such large values?

Maybe I'm thinking far ahead of my current knowledge (which I would rate as beginner), however, if the newly created matter is not accounted in this model, by any chance could our mysterious dark matter be what is created but cannot be observed because of the time delay, which, I could expect to get answer to even in my thread about https://www.physicsforums.com/showthread.php?p=2854997" , which I could relate to motion of the spin-2 and massless gravitons in "certain" conditions.


Exactly what "newly created matter" are you referring to?.

Even if we accepted the idea of such matter springing from nothing, we wouldn't see the effect it has on other objects any sooner than we would see it.
 
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