Final answer:
Gravitational lensing and observations of the cosmic microwave background radiation can help eliminate high gravitational fields as the source of galactic red shifts. Comparing red shifts to galaxy sizes is not a valid method. The primary cause of galactic red shifts is the proportional relation to distance.
Step-by-step explanation:
Gravitational lensing can help eliminate high gravitational fields as the source of galactic red shifts. When light passes close to a massive object, such as a galaxy, its path is bent due to gravity, creating multiple images of the same object.
By studying these gravitational lensing effects, astronomers can verify that the red shift is proportional to distance, providing evidence that high gravitational fields are not the cause of galactic red shifts.
Observations of the cosmic microwave background radiation can also help eliminate high gravitational fields as the source of galactic red shifts.
The cosmic microwave background radiation is the remnant radiation from the early universe and is uniform in all directions. By comparing the red shifts observed in galaxies to the uniform background radiation, astronomers can determine that the red shifts are due to the expansion of space and not high gravitational fields.
Comparing the red shifts of galaxies to their sizes is not a valid way to eliminate high gravitational fields as the cause of galactic red shifts.
The red shifts are proportional to distance, not the size of the galaxy. Therefore, the size of the galaxy does not affect the red shift, making it an unreliable factor in determining the cause of the red shifts.
The key factor in eliminating high gravitational fields as the source of galactic red shifts is considering the proportional relation to distance.
Since the red shifts are proportional to distance, it indicates that the light from distant galaxies is being stretched as the space between them and us expands. This expansion of space is the primary cause of the observed red shifts in galaxies.