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genefalk
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Why aren't the other bands (visible, UV, etc.) in the electromagnetic spectrum also seen today as part of the background radiation?
genefalk said:If the background radiation that we see today were in the visible range (for example red), would the night sky be red instead of black?
The main reason for observing only microwaves in the background radiation is because of the expansion of the universe. This radiation, also known as the Cosmic Microwave Background (CMB), was emitted about 380,000 years after the Big Bang. As the universe expanded, the wavelengths of this radiation stretched and shifted towards longer wavelengths, which fall within the microwave range.
Yes, the CMB is the same in all directions. This is one of the key pieces of evidence for the Big Bang theory. The CMB is a remnant of the hot, dense state of the early universe, and as the universe expanded, the radiation became more uniform and isotropic. This is known as the isotropy of the CMB.
Yes, there are small variations in the CMB that can be detected in other wavelengths, such as infrared and radio waves. These variations are important in understanding the structure and evolution of the universe, and they can also provide clues about the properties of dark matter and dark energy.
The CMB is a crucial piece of evidence for the Big Bang theory. Its uniformity and isotropy support the idea that the universe was once in a hot, dense state and has been expanding ever since. The CMB also contains small variations, known as anisotropies, which can be studied to learn more about the early universe and its evolution.
No, we cannot see the CMB with the naked eye. The CMB is a form of electromagnetic radiation, which is invisible to the human eye. It can only be detected and studied using specialized equipment, such as telescopes and detectors designed to pick up microwaves.