Background radiation and intensity

In summary, the conversation discusses the concept of the universe expanding, as evidenced by the uniform microwave radiation detected from all directions. This leads to the question of whether we are at the center of the universe, but the analogy of a raisin in a loaf of bread explains that the perception of being at the center is relative and the distance between everything is increasing everywhere.
  • #1
peleus
18
0
Hi all,

Quick question. I'm reading through Stephen Hawking's a brief history of time (interesting even though I can only understand 1/10th of it).

During this book he consistently mentions the fact the microwave radiation detected is near uniform in all directions, which is evidence that the universe is expanding as the wavelengths are red shifting.

This leads me to the question, does this also mean that we are in the center of the universe? I'm modest enough to believe this is almost certainly not the case, however where is my thinking wrong. To me equal radiation says that the waves have traveled a roughly similar distance to get to us as they are red shifted the same amount, however let's say the universe stretched 1 million light-year's east of us, and 20 million light-years west of us (for want of a better way of describing it simply) wouldn't the microwave radiation coming from the west be red-shifted a further amount due to the fact is has traveled longer? Should there be different intensities if that was the case?

I have no doubt my reasoning is wrong, however I'm looking to find out why it is wrong

Thanks.

Edit: I think I just figured out the answer but I'll see if people respond with the same reason I'm thinking.
 
Last edited:
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  • #2
Think of the universe as being a loaf of bread, and the Earth is a raisin. When you cook the bread, the dough expands in all directions. From the point of view of any raisin, it looks like all the other raisins are getting further away from you. From the raisin's perspective it may seem like it is in the center of the universe and everything else is expanding away from it. But the reality is that the distance between everything is increasing everywhere.
 
  • #3
We are at the center of the universe. We are also at the furthest edge of the universe. The center and edge of the universe appears to be wherever [and whenever] you happen to be. It's like trying to find the center [or edge] of the surface of a sphere.
 

Related to Background radiation and intensity

1. What is background radiation?

Background radiation refers to the constant low levels of radiation that are present in our environment. These can come from natural sources such as cosmic rays, radioactive materials in the soil, and even our own bodies, or from human-made sources such as nuclear power plants and medical procedures.

2. Is background radiation harmful?

In small doses, background radiation is not harmful to human health. Our bodies have evolved to adapt to low levels of radiation, and we are constantly exposed to it in our daily lives. However, prolonged exposure to high levels of background radiation can increase the risk of health problems such as cancer.

3. How is the intensity of background radiation measured?

The intensity of background radiation is typically measured in units of millisieverts (mSv) per year. This unit takes into account both the amount of radiation and the potential harm it can cause to human health. A typical person is exposed to an average of 2.4 mSv of background radiation per year.

4. What factors can affect the intensity of background radiation?

The intensity of background radiation can vary depending on location and altitude. Places with higher levels of radioactive materials in the soil, such as granite-rich areas, tend to have higher levels of background radiation. Altitude also plays a role, as the higher you are in the atmosphere, the more exposure you have to cosmic rays.

5. How can we protect ourselves from background radiation?

Since background radiation is present everywhere, it is impossible to completely avoid exposure. However, there are some steps we can take to minimize our exposure, such as limiting time spent in high-altitude or high-radiation areas, using protective equipment in certain occupations, and following proper safety protocols in medical procedures that involve radiation.

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