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wolram
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How do we know that the cmb is not just related to just our galaxy, and that all galaxies have there own cmb?
But I think the OP is asking: suppose you measure a 2.7K microwave. How do you know it didn't come from our galaxy? Extrapolating via redshift presumes that it is a CMB photon.rootone said:Also because we can determine the amount of redshift, we can make reasonable estimates of how old it is and how far away it is.
Since it is older than our galaxy and more distant than any galaxies we can see, then it can't be anything to do with our own galaxy.
The cosmic microwave background (CMB) is the remnant radiation from the Big Bang, also known as the afterglow of the creation of the universe. It is a faint glow of microwave radiation that permeates the entire observable universe.
The CMB was discovered in 1964 by two scientists, Arno Penzias and Robert Wilson, who were working with a radio telescope. They noticed a persistent noise in their equipment that seemed to come from every direction in the sky, which turned out to be the CMB radiation.
The CMB carries important information about the early universe, such as its age, composition, and rate of expansion. It also helps us understand the structure and evolution of the universe, including the formation of galaxies and large-scale structures.
The CMB is considered one of the strongest pieces of evidence for the Big Bang theory. Its existence and properties, such as its uniformity and thermal radiation, align with the predictions of the theory. It also supports the idea that the universe was once much hotter and denser than it is now.
Yes, we can still observe the CMB today, although it has cooled significantly since its discovery. It now has a temperature of about 2.73 Kelvin (-270.42 degrees Celsius), which is still detectable by specialized instruments. Scientists continue to study the CMB to gain more insight into the secrets of the universe.