Question regarding red shift and tired light hypothesis

In summary, the conversation discusses the idea of distant objects receding from us and producing a redshift, which is a fundamental concept in current cosmological thinking. There have been alternate ideas proposed in the past, such as the tired light hypothesis, but these have been refuted. It is mentioned that the decrease in luminosity due to recession is too small to be detected with current technology. The conversation also touches on the expansion of space and the implications for distance between objects. The possibility of measuring changes in magnitude over time is discussed, with the idea that current instrumentation may be sensitive enough to make such measurements.
  • #1
rrosenthal
16
0
The idea that distant objects are receeding from us and thereby producing a proportional redshift --seems to be a fundamental tenant in terms of current cosmological thinking and theory. There have been alternate ideas proposed in the past including the tired light hypothesis-(whereby light traveling at great distances gives up energy to space and that this is what produces the red shift---still proportional to distance). If very distant objects are in fact receeding from us, they ought to be growing fainter in magnitude. Has this ever been measured ?? I wonder if the magnitude of distant objects on plates taken 20-30 years ago have ever been compared to present day magnitude of the same objects---to see-- if on average-- they have become slightly fainter. I wonder if our instruments are sensitive enough to make such a determination ?

Randy Rosenthal
 
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  • #2
rrosenthal said:
The idea that distant objects are receeding from us and thereby producing a proportional redshift --seems to be a fundamental tenant in terms of current cosmological thinking and theory. There have been alternate ideas proposed in the past including the tired light hypothesis-(whereby light traveling at great distances gives up energy to space and that this is what produces the red shift---still proportional to distance). If very distant objects are in fact receeding from us, they ought to be growing fainter in magnitude. Has this ever been measured ?? I wonder if the magnitude of distant objects on plates taken 20-30 years ago have ever been compared to present day magnitude of the same objects---to see-- if on average-- they have become slightly fainter. I wonder if our instruments are sensitive enough to make such a determination ?

Randy Rosenthal

From what I know Doppler shift is based on this and the usage of it's formula tellls us whether Object "X" radial velocity is approaching us or not but this isn't why you posted this thread.So in tired light hypothesis what exactly happens to the light itself? does it give a proportion of it's energy or does it exhaust? if we are to assume that energy is absorbed by the interstellar dust then wouldn't that actually produce anomaly itself towards the data which we have observed since the absorbed "energy"/photons are radiated in random direction. Sorry if I am deviating the subject of this thread,just a thought which just sprung my mind.I apologize If I got the wrong idea.
 
  • #3
The decrease in luminosity due to recession is so miniscule it would take hundreds of thousands of years to detect using current technology. Don't worry about 'tired light'. That conjecture has been thoroughly refuted. Note that cosmological redshift is not the same as doppler shift. Here is a good article addressing this subject:
http://www.astronomycafe.net/cosm/expan.html
 
  • #4
Chronos said:
The decrease in luminosity due to recession is so miniscule it would take hundreds of thousands of years to detect using current technology. Don't worry about 'tired light'. That conjecture has been thoroughly refuted. Note that cosmological redshift is not the same as doppler shift. Here is a good article addressing this subject:
http://www.astronomycafe.net/cosm/expan.html

Ah thank you very much.
 
  • #5
ibysaiyan said:
if we are to assume that energy is absorbed by the interstellar dust then wouldn't that actually produce anomaly itself towards the data which we have observed since the absorbed "energy"/photons are radiated in random direction.

I was taught that this was not the case, that absorbed light would be retransmitted in the same direction just at a different wavelength otherwise this absorption would account for Olbers paradox! I apologise if I have misunderstood or misinterpreted the above statement.

From Wiki:
"However, this reasoning alone would not resolve the paradox given the following argument: According to the second law of thermodynamics, there can be no material hotter than its surroundings that does not give off radiation and at the same time be uniformly distributed through space. Energy must be conserved, per the first law of thermodynamics. Therefore, the intermediate matter would heat up and soon reradiate the energy (possibly at different wavelengths). This would again result in intense uniform radiation."
 
  • #6
Chronos said:
The decrease in luminosity due to recession is so miniscule it would take hundreds of thousands of years to detect using current technology. Don't worry about 'tired light'. That conjecture has been thoroughly refuted. Note that cosmological redshift is not the same as doppler shift. Here is a good article addressing this subject:
http://www.astronomycafe.net/cosm/expan.html

Read the article you gave me. I have 2 comments---1st---"gravitational" redshift quoted in the article sounds like another version of the "tired light" hypothesis in the sense that red shift observed--(as a result of passing thru gravitational fields) is still --it seems to me--a function of distance transversed rather than a receeding of objects from one another or an increase in distance between the 2 objects. The Einsteinien notion that space is what is expanding between objects still seems to imply an increasing--rather than static--distance between the objects. I may be mistaken, but the whole expansion idea still seems based upon the redshift observations. 2nd comment---Current theory says that the most distant objects may be receeding from us at light --or greater than light speed--(given that space is what is expanding). This implies an increase of at least 1 light yr in distance increase per yr---or 20 light yrs of distance if the comparison plate is 20 yrs old. The objects are billions of light yrs away---still 20 parts per several billion may be close. I seem to remember reading several yrs ago --?--that instruments could detect magnitude changes of 1 part per billion---perhaps instrumentation is more sensitive now----if so, one would not have to wait centuries to make this kind of experiment---?----R Rosenthal
 
  • #7
rrosenthal said:
Read the article you gave me. I have 2 comments---1st---"gravitational" redshift quoted in the article sounds like another version of the "tired light" hypothesis in the sense that red shift observed--(as a result of passing thru gravitational fields) is still --it seems to me--a function of distance transversed rather than a receeding of objects from one another or an increase in distance between the 2 objects. The Einsteinien notion that space is what is expanding between objects still seems to imply an increasing--rather than static--distance between the objects. I may be mistaken, but the whole expansion idea still seems based upon the redshift observations. 2nd comment---Current theory says that the most distant objects may be receeding from us at light --or greater than light speed--(given that space is what is expanding). This implies an increase of at least 1 light yr in distance increase per yr---or 20 light yrs of distance if the comparison plate is 20 yrs old. The objects are billions of light yrs away---still 20 parts per several billion may be close. I seem to remember reading several yrs ago --?--that instruments could detect magnitude changes of 1 part per billion---perhaps instrumentation is more sensitive now----if so, one would not have to wait centuries to make this kind of experiment---?----R Rosenthal

Unfortunately that kind of measurement is still beyond the realm of current (or near-term) technology. I'd add that concept of "tired light" is based in a larger notion of conservation of energy that may not apply to the universe as a whole.

edit: I'd add, those measurements we can make, as Chronos said, refutes the notion.
 
  • #8
I hope you aren't referring to photographic plates - there is no accurate means of comparing them to CCD images. Measuring a stars brightness is based on comparisons with other stars - standard stars. BUT how standard are the standard stars? Everything is moving, everything evolves and all stars change brightness over long periods of time. The very best photometric measurements go to 4-5 decimal places - that's it - but when they are compared to standards that only go to 3 decimal places, well we are a long, long way short of 1 part per billion. Variations in the Earth's atmosphere will be enough to throw out plate to plate comparisons in any case. Hubble would fair better but we are back to the physical constraints of the well depth on CCD chips.

Also, gravitational redshift doesn't imply a loss in energy of light so although the result that we observe may be the same, it is nothing like 'tired' light'.

Cheers

David
 

1. What is the red shift phenomenon?

The red shift phenomenon is the observation that light from distant objects, such as galaxies, appears to be shifted towards the red end of the electromagnetic spectrum. This is due to the expansion of the universe, causing the wavelengths of light to be stretched as it travels towards us.

2. What is the tired light hypothesis?

The tired light hypothesis is an alternative explanation for the red shift phenomenon. It suggests that the red shift is not caused by the expansion of the universe, but rather by the gradual loss of energy, or "tiredness," of light as it travels through space.

3. How does the tired light hypothesis differ from the Big Bang theory?

The Big Bang theory is the widely accepted explanation for the red shift phenomenon and the expansion of the universe. It proposes that the universe began with a sudden explosion and has been expanding ever since. The tired light hypothesis, on the other hand, suggests that the universe has always existed and that the red shift is caused by the gradual loss of energy in light.

4. What evidence supports the Big Bang theory over the tired light hypothesis?

There is a significant amount of evidence supporting the Big Bang theory, including the cosmic microwave background radiation, the abundance of light elements in the universe, and the large-scale structure of the universe. Additionally, the tired light hypothesis has been unable to explain the observed red shift in all cases, whereas the Big Bang theory can account for it in a consistent and accurate manner.

5. Are there any scientists who support the tired light hypothesis?

While the majority of scientists accept the Big Bang theory as the most accurate explanation for the red shift phenomenon, there are some who continue to explore the tired light hypothesis. However, the evidence and support for the Big Bang theory remain overwhelmingly strong in the scientific community.

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