Where Would Ancient Intelligent Life Have Seen Cosmic Background Radiation?

In summary, if intelligent life had evolved on a planet 6.8 billion years ago, they would have seen the cosmic background radiation at a peak frequency of 290GHz, still within the microwave range. This is because at that time, the CMB temperature would have been 4.9K, and the first stars formed when the CMB was in the microwave/millimeter wave range.
  • #1
newphy
3
0
If intelligent life had evolved on some planet 6.8 billion years ago (half the time to the big bang 13.6 bilion years ago) and they had sent the equivalent of the COBE / Planck satellite to map the cosmic background radiation, where in the electromagnetic spectrum would they have seen the radiation? I assume it would not have redshifted to the microwave region at that time.
Thanks
 
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  • #2
The scale factor 6.8 billion years ago was at roughly ##a=0.55##, which means the CMB temperature would have been ##2.725K/0.55=4.9K##. so the CMB would have a peak at around 290GHz, which would still be well within the microwave range.

Edit:
I guess to be more pedantic, it's actually in the millimeter wave range. But it's closer to the microwave range than it is currently.
 
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  • #3
Also, the first stars formed when the scale factor was at around roughly 1/20th its current value, which means the CMB peak frequency would have been at around 90 microns. Thus the CMB has been in the microwave/millimeter wave range for the entire time that stars have been around.
 

Related to Where Would Ancient Intelligent Life Have Seen Cosmic Background Radiation?

What is cosmic background radiation?

Cosmic background radiation is a type of electromagnetic radiation that permeates the entire universe. It was first discovered in 1964 by Arno Penzias and Robert Wilson, and is believed to be leftover radiation from the Big Bang.

How is cosmic background radiation measured?

Cosmic background radiation is measured using a device called a radiometer, which is designed to detect and measure microwave radiation. This radiation is then analyzed and mapped to create a visual representation of the cosmic background radiation.

Why is cosmic background radiation important to study?

Studying cosmic background radiation is important because it provides valuable information about the early universe and the origins of our universe. It also helps us understand the structure and evolution of the universe, as well as the distribution of matter and energy within it.

What is the significance of the Cosmic Microwave Background (CMB) in relation to cosmic background radiation?

The Cosmic Microwave Background (CMB) is a specific type of cosmic background radiation that has a blackbody spectrum at a temperature of 2.7 Kelvin. It is believed to be the oldest light in the universe and provides evidence for the Big Bang theory.

How does cosmic background radiation support the Big Bang theory?

The discovery of cosmic background radiation and the subsequent observation of its consistency with the predictions of the Big Bang theory provide strong evidence for the theory. Additionally, the fluctuations in the cosmic background radiation allow us to study the early universe and confirm key aspects of the Big Bang model, such as the expansion of the universe and the formation of galaxies and large-scale structures.

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