- #1
pedong
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is there a certain physical thing that you can see with your naked eyes, but it doesn´t exists anymore.
Nostalgia for a Physical Thing That No Longer Exists
- Thread starter pedong
- Start date
In summary, there are physical things that can be seen with the naked eye but no longer exist, such as quasars and proto-galaxies. This is due to the finite speed of light and the fact that photons, which are necessary for us to see, cease to exist upon being absorbed. This concept can be compared to how optical telescopes and the human eye function.
- #2
cmos
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Photons.
- #3
jarmour3
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cmos said:
I was under the impression that photons exist and that they were completely stable particles that did not decay. On the other hand, if you consider astrophysical phenomena, quasars and proto-galaxies that can be seen in the distant reaches of space no longer exist but can be seen because of the finite speed of light. I know that these bodies are not observed with the naked eye, but optical telescopes and the camera on the Hubble telescope are, in many ways, analogous to the human eye because they are all diffraction pattern sensors.
- #4
cmos
- 367
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Clearly we can see visible light. But to see visible light your eye has to absorb a photon. Once absorbed, that photon ceases to exist. 
- #5
Defennder
Homework Helper
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Brilliant. I never thought of that.
- #6
russ_watters
Mentor
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Clever, if this is a riddle. Is it...?
FAQ: Nostalgia for a Physical Thing That No Longer Exists
1. What is nostalgia for a physical thing that no longer exists?
Nostalgia for a physical thing that no longer exists refers to the feeling of longing or sentimentality for a physical object or experience that is no longer accessible or present in one's life. It can be triggered by memories, photographs, or even discussions about the object or experience.
2. Why do people feel nostalgia for things that no longer exist?
Nostalgia is a common human emotion that is often triggered by feelings of loss or change. People may feel nostalgic for physical things that no longer exist because they represent a time or place in their lives that was meaningful or significant. Nostalgia can also provide a sense of comfort and familiarity in a constantly changing world.
3. Is nostalgia for a physical thing that no longer exists a positive or negative emotion?
Nostalgia for a physical thing that no longer exists can be both positive and negative. It can bring about happy memories and a sense of warmth and comfort, but it can also evoke feelings of sadness or longing for something that is no longer attainable. The emotional response to nostalgia can vary from person to person.
4. Can nostalgia for a physical thing that no longer exists be harmful?
In most cases, nostalgia for a physical thing that no longer exists is a harmless and natural emotion. However, if the feelings of nostalgia become overwhelming or interfere with daily life, it may be a sign of a larger issue such as depression or anxiety. It is important to seek professional help if nostalgia becomes a persistent and negative emotion.
5. How can nostalgia for a physical thing that no longer exists be beneficial?
Nostalgia can be beneficial in many ways. It can provide a sense of connection to the past and help people maintain a sense of identity. Nostalgia can also serve as a source of inspiration and creativity, as people often look to the past for ideas and inspiration. Additionally, nostalgia can bring people together and foster a sense of community and shared experiences.