MCQ Detailed View

Dark matter is a mysterious form of matter that makes up about 27% of the total mass-energy of the universe, yet it cannot be seen directly through telescopes. The main reason for this invisibility is that dark matter does not interact with electromagnetic force, meaning it does not emit, absorb, or reflect light or any other form of electromagnetic radiation.

Telescopes, whether optical, radio, or X-ray, detect light and other electromagnetic waves. Ordinary matter, like stars and planets, is visible because it interacts with electromagnetic forces, producing or reflecting light that telescopes can capture. Dark matter, however, interacts primarily through gravity, pulling on visible matter and influencing the movement of galaxies, but it does not produce detectable light signals.

This lack of electromagnetic interaction means:

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  Dark matter cannot be seen directly.

  
  


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  It is transparent to all wavelengths of light.

  
  


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  Its existence is inferred only through gravitational effects, such as:

  
  
  
  
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    The rotation speed of galaxies (stars orbiting too fast to be explained by visible matter alone).

    
    
  
  
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    Gravitational lensing, where light from distant galaxies is bent by unseen massive structures.

    
    
  
  
  
  

Scientists believe dark matter consists of particles that neither absorb nor emit photons, making it invisible to telescopes. Specialized detectors and experiments are being developed to try to capture signs of these particles, but none have been confirmed yet.

Key points:

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  Dark matter makes up a large portion of the universe's mass.

  
  


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  It interacts gravitationally but not electromagnetically.

  
  


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  Its presence is detected only by its effect on visible matter and light paths.

  
  

Thus, the correct answer is: C. Dark matter does not interact with electromagnetic force.