Georgina Woodward
A different idea about red - shift
All of the galaxies except the nearest, the local group, appear red-shifted. Conventionally explained as due to movement away from the observer, Doppler-like, implying the expansion of the seen universe , in all directions since its formation.
The environment of space has, until recently been thought to be a vacuum, accounting for the longevity of photons in space.
What if instead between source and observer is dust?
An object will absorb photons but dust might absorb some photons and allow other’s through It’s heating may lead to the emission of new red wavelengths.
from AI overview by google search
''Particles absorb photons by capturing their energy when the light wave interacts with the particle, essentially "soaking up" the photon's energy, which is then converted into heat and can sometimes cause structural changes within the dust grain itself; this process is particularly prominent with shorter wavelengths of light, like ultraviolet, causing dust clouds to appear dark against a starry background while re-emitting the absorbed energy at longer infrared wavelengths.
Key points about dust particle photon absorption in space:
• Wavelength dependence:
Smaller dust particles tend to absorb more light at shorter wavelengths (like ultraviolet) while larger particles can absorb across a broader spectrum.
• Re-emission:
When dust particles absorb photons, they re-emit the energy as infrared radiation, making dusty regions appear bright in infrared images.
• Impact on observation:
Dust absorption significantly affects our view of distant stars and galaxies, obscuring details in certain wavelengths, especially in regions with dense dust clouds.
How it works:
• Interaction with the dust grain:
When a photon strikes a dust particle, it can be absorbed if its wavelength matches the resonant frequency of the particle's material. Energy transfer:
The absorbed energy is then transferred to the dust particle, exciting its atoms or molecules, causing them to vibrate and heat up.
• Emission of infrared radiation:
The heated dust particle then re-radiates the absorbed energy as infrared radiation, which has a longer wavelength than the original photon.
dust in space:
• Interstellar dust:
Dust particles present between stars within a galaxy, composed of elements like carbon, silicon, and oxygen.
• Circumstellar dust:
Dust particles surrounding a star, often created by stellar winds or planetary nebulae.
• Interplanetary dust:
Dust particles within our solar system, contributing to the zodiacal light.
The energy of the photon is converted into another form of energy, and is lost to us: the photon is absorbed. Again, the effect of absorption is to decrease the amount of light we detect from the star. Very often, the dust grain will emit other photons, but at much longer wavelengths, typically in the IR.''
'Institute of computational cosmology'
This seems to show that for galaxies further away than the local group, for whom ‘light’ has had to travel further to reach us have been red-shifted
because of the effect of dust. How much will depend on the type, amount and interference caused by it.
Local group galaxies can be blue- shifted .Thought to indicate movement towards the observer. The light has less far to travel through space to reach an observer. Therefore it is likely that the interaction with dust will be less and not enough to counteract the effect causing blue-shift
