Why do we need electromagnetic waves?

The 'static' fields are just the lowest energy part of the spectrum.In summary, the presence of oscillating electromagnetic fields is necessary for the existence of life on Earth. This is because life evolved in a universe where electromagnetic fields exist and play a crucial role. The sun's magnetic field, which is primarily static, is not enough to support life as it cannot transport energy across a vacuum. Additionally, we and other animals are able to see objects because of the oscillating nature of EM fields, particularly visible light, which is energetic enough to cause chemical changes and is abundant due to our sun's output.
  • #1

kent davidge

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(Sorry for my poor english.) I'm just wondering why is it necessary to have oscillating EM fields for life existing on Earth. The sun has a magnetic field (I think a static one), so why it's not enough to life exists? Also, why we and other animals only see the objects if the fields are oscillating?
 
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You have taken a very anthropomorphic posture--as though life is the important thing while physical nature and laws are secondary. In our universe, there are electromagnetic fields. That's the starting point. Life was able to evolve, partly as a result. We see visible light because a) it is energetic enough to cause chemical changes, which organisms can exploit, b) because the wavelengths are small enough that we can build an antenna with gain (lens) that is a reasonable size relative to our bodies, and c) because our sun puts out copious energy in that range (and our atmosphere allows it to reach the surface).
 
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  • #3
kent davidge said:
The sun has a magnetic field (I think a static one), so why it's not enough to life exists?
Static EM fields can't transport energy across a vacuum.

But I agree with marcusl that the question is kind of backwards, like life causes EM.
 
  • #4
kent davidge said:
(Sorry for my poor english.) I'm just wondering why is it necessary to have oscillating EM fields for life existing on Earth. The sun has a magnetic field (I think a static one), so why it's not enough to life exists? Also, why we and other animals only see the objects if the fields are oscillating?
Light is only a very small portion of the whole spectrum of EM waves. It spans from the very lowest frequency of electrical oscillations (50Hz mains electricity) up to the highest energy Gamma Rays 1019Hz. They all involve time varying E and H fields.
 

Why do we need electromagnetic waves?

Electromagnetic waves are essential for many aspects of our modern lives. Here are five frequently asked questions about their importance:

What are electromagnetic waves?

Electromagnetic waves are a form of energy that can travel through space. They are created by the movement of electrically charged particles and do not require a medium to propagate.

How do electromagnetic waves benefit us?

Electromagnetic waves have a wide range of practical applications. They are used in communication technologies such as radio, television, and cell phones. They also play a crucial role in medical imaging, as well as in the production of electricity through power plants.

Why can't we see electromagnetic waves?

Although we cannot see electromagnetic waves with our eyes, we can detect them through other means, such as with specialized equipment. This is because the wavelengths of electromagnetic waves are outside of the visible spectrum.

What is the relationship between electromagnetic waves and light?

Light is a type of electromagnetic wave. It is the only type of electromagnetic wave that we can see with our eyes. Other forms of electromagnetic waves, such as radio waves, microwaves, and X-rays, have different wavelengths and frequencies.

Can electromagnetic waves be harmful?

High levels of exposure to certain types of electromagnetic waves, such as X-rays and gamma rays, can be harmful to living organisms. However, most forms of electromagnetic waves, such as visible light and radio waves, are not harmful to humans in small doses.

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