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Summary by a commenter in the link: Radio astronomy observations of Pulsars indicate that the Hubble Red Shift is caused by “Tired Light” rather than the expans
by behnamoh 4y ago
Summary by a commenter in the link: Radio astronomy observations of Pulsars indicate that the Hubble Red Shift is caused by “Tired Light” rather than the expansion of the universe.
When Hubble published his observations of red shifted light from distant objects there were two possible explanations that came to the fore. One, originated by Georges Lemaitre, was that the Universe was expanding. The other, from Fritz Zwicky, was that light lost energy as it traveled, termed "tired light". At that time, ca. 1930, interstellar and intergalactic space were assumed to be perfect vacuums and thus there was no mechanism to redden the light. Now, 90 years later, we have actual observational evidence that Zwicky was right.
In the radio astronomy of Pulsars we find that the shorter wavelengths of the leading edge of the pulse arrive before longer wavelengths. The velocity of light, c, is NOT constant but varies by wavelength. This time dispersion is proportional to the distance from us of the pulsar, indicating that the reduction in velocity is cumulative. The observed effect is isotropic. The interstellar medium is not a vacuum but rather affects light waves in a way best described as having an Index of Refraction greater than 1, unity. We find the same phenomenon in the observation of Fast Radio Bursts from other galaxies, thus indicating that the intergalactic media is not an electromagnetic vacuum.
- ramesh31 4y agoSounds like this commenter should write a paper.
- DiggyJohnson 4y agoI think it would be more apt to suggest they write/consult for science programming, but I certainly agree with your sentiment.
- kurupt213 4y agowhy, it won't make it through peer review. high frequency light arrives first because it interacts less with matter. remember, c is only constant in a true vacuum. the speed of light varies as it travels through matter (refraction). there is a lot of "stuff" to interact with between us and a galaxy 14 billion light years away i wonder if the energy of empty space (yes, empty space has energy) plays a role in slowly dissipating the energy from light.
- ramesh31 4y ago>why, it won't make it through peer review. That was my point.
- andrewclunn 4y agoSo no unavailable pitch black sky save for our local group? This is the best freaking cosmological news I've ever heard!
- peterlk 4y agoOk…. So I’m going to try to rephrase what I just learned from this comment. Can someone tell me how far off I am? The universe is not 100% empty, so the index of refraction is not 1. This could be explained by lots of phenomena like dust particles or stray radiation, etc. Because of this effect, for practical purposes, light that we see as res “travels slower” because it has traveled through more media than blue light.
- starwind 4y agoCurious, I googled "In the radio astronomy of Pulsars we find that the shorter wavelengths of the leading edge of the pulse arrive before longer wavelengths. The velocity of light, c, is NOT constant but varies by wavelength" and something interesting came up: "interstellar clouds of electrons retard the velocity of radio waves in direct proportion to their wavelength" in an article from a 1968 edition of Scientific American written by Anthony Hewish...the same guy who discovered pulsars
- eecc 4y agoLook up Hannes Halven then, also very interesting.
- 8bitsrule 4y agoDispersion has been evident since FRBs were discovered in 2007. [https://en.wikipedia.org/wiki/Fast_radio_burst https://en.wikipedia.org/wiki/Fast_radio_burst] "The component frequencies of each burst are delayed by different amounts of time depending on the wavelength. This delay is described by a value referred to as a dispersion measure (DM). This results in a received signal that sweeps rapidly down in frequency, as longer wavelengths are delayed more." [https://en.wikipedia.org/wiki/Dispersion_(optics)#Pulsar_emissions https://en.wikipedia.org/wiki/Dispersion_(optics)#Pulsar_emi...] "dispersion measure (DM) is the column density of free electrons (total electron content) — i.e. the number density of electrons (electrons/cm3) integrated along the path traveled by the photon from the pulsar to the Earth"
- pdonis 4y ago> Tired Light Is a hypothesis that, as a sole or primary explanation of observed redshifts of galaxies, has been thoroughly debunked in the scientific literature. > the intergalactic media is not an electromagnetic vacuum This is true, but it cannot explain the observed data by itself, because the observed data is not "redshifts" by themselves. The observed data is a combination of redshifts, apparent luminosity, and angular size for thousands of observed galaxies. These data have observable relationships that can only be explained by cosmological expansion. If the redshifts were caused solely by dispersion in the intergalactic medium, their relationships with apparent luminosity and angular size would be very, very different. That is a quick summary of the thorough debunking of "tired light" that can be found in the scientific literature over a period of some decades.
- Ekaros 4y agoInter galactic space not being empty makes lot of sense. After all everything that is matter(stars etc.) had to come from somewhere. If universe is expanding is it getting thinner? That is same amount of matter is spreading over larger space. Thus wouldn't the refraction index be higher on average when observing the path from really old objects?