explain why some galaxies and distant stars red in color (Redshifted)
The phenomenon of redshifted galaxies and distant stars being red in color is attributed to the expansion of the universe. As the universe expands, the space between galaxies and stars also stretches. This stretching causes the wavelengths of light emitted by these cosmic objects to also stretch, leading to a shift towards longer wavelengths, which are in the red part of the electromagnetic spectrum.
This shifting of wavelengths is known as redshift. It occurs because the expansion of the universe causes the stretching of the waves of light, similar to how the stretching of a sound wave would lower its pitch. As a result, the light from these distant objects that reaches us on Earth appears shifted towards longer, redder wavelengths.
The amount of redshift observed in an object's light is directly related to its distance from Earth. Since light travels at a finite speed, the light from distant galaxies and stars takes a significant amount of time to reach us. Therefore, when we observe a galaxy or a distant star, we are seeing it as it existed in the past. The greater the redshift, the further away the object is and the farther back in time we are observing it.
The redshift data collected by astronomers has been used to determine that the universe is in a state of expansion and to estimate the age of the universe. Additionally, redshift information can help determine the velocity with which galaxies are moving away from us. This data has led to the development of the Big Bang theory, which suggests that the universe began with a rapid expansion from a single point.