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Thread: Where does light go

  1. #1 Where does light go 
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    The speed of light is a given, my question is where does it go. is there a point where light dissapates after traveling, or does it's waves continue on.

    Black holes gravity it is said pulls light into its vortex, is such holes the destination of all spacial light.


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    Light can continue to travel through space forever, but as it travels, it loses intensity as governed by the inverse square law. Black holes (assuming they exist), are not necessarily the ultimate destination for light waves, it simply depends on what direction they are travelling in. If they collide with a black hole, they are trapped. If they don't, they are free to continue on their merry way.


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    Light also interacts with matter on it's journey. It could heat up matter or cause ionisation, converting some of it's energy in the process.
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  5. #4 Re: Where does light go 
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    Quote Originally Posted by curious1
    The speed of light is a given, my question is where does it go. is there a point where light dissapates after traveling, or does it's waves continue on.

    Black holes gravity it is said pulls light into its vortex, is such holes the destination of all spacial light.
    The photons that constitute light can travel indefinitely in a vacuum without loss of energy. So-called "tired light" theories are without merit. The intensity of light, which is the density of photons, decreases as the square of the distance from a point source.

    A photon that encounters an atom may be absorbed, excitintg an electron. When the electron relaxes a photon is emitted. A photon that enters a black hole cannot escape. But there is a quantum phenomenon, called Hawking radiation, that if correct predicts that black holes can emit photons and will eventually evaporate through that mechanism.
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  6. #5 Re: Where does light go 
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    Quote Originally Posted by DrRocket

    The photons that constitute light can travel indefinitely in a vacuum without loss of energy.
    What's vacuum energy, How does/doesn't this interact with photons?
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  7. #6 Re: Where does light go 
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    Quote Originally Posted by Geo
    Quote Originally Posted by DrRocket

    The photons that constitute light can travel indefinitely in a vacuum without loss of energy.
    What's vacuum energy, How does/doesn't this interact with photons?
    http://en.wikipedia.org/wiki/Vacuum_energy

    http://en.wikipedia.org/wiki/Zero_point_energy
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  8. #7  
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    If i shined a light on a flat plane to a particular point some miles away if i cant register the lights arrival at said point by wave or visual, then how can some say it reached said point. So if I cant see the light on a straight plane of miles then how can we say it's speed equals in actual distance forever.

    If intensity binds it all that is meant is that Yes at some point it dissapates.

    Rather a light waves have a destination outside of a pull from a alleged Black hole which by the way is said to be all around in space, then that pull would negate our gravity as having a influence on it.

    Granted we dont really know everything, so why do we act like we do. To me this is a murder of scientific study.



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  9. #8  
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    Quote Originally Posted by Geo
    Light also interacts with matter on it's journey. It could heat up matter or cause ionisation, converting some of it's energy in the process.
    What energy is within light outside of its source which seems to me to be Heat.
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  10. #9  
    Geo
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    Quote Originally Posted by curious1
    Quote Originally Posted by Geo
    Light also interacts with matter on it's journey. It could heat up matter or cause ionisation, converting some of it's energy in the process.
    What energy is within light outside of its source which seems to me to be Heat.
    Electromagnetic waves are a form of energy. This energy can be converted into other forms of energy.

    If you mean visible light, it doesn't heat anything up, infra-red could. As Dr. Rocket stated visible light could cause excitation of electrons in atoms. Gamma rays which are also a form of light can cause ionisation.
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  11. #10  
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    Quote Originally Posted by curious1
    Quote Originally Posted by Geo
    Light also interacts with matter on it's journey. It could heat up matter or cause ionisation, converting some of it's energy in the process.
    What energy is within light outside of its source which seems to me to be Heat.
    Light is energy. It is the energy released when an electron moves from a state of higher energy to a state of lower energy. When an electron absorbs a photon it moves to a higher energy state, and in the extreme it becomes separated from the atom and this is called ionization.

    Heat is the energy of motion of molecules and that is reflected in the energies of the electrons in the atoms that comprise the molecules.

    You need to take a course in physics.
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    the light that a fire produces dissipates... I would think sun light does also, unless it behaves differently in space or in certain space environments? How can it travel forever as someone stated above?
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  13. #12  
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    Quote Originally Posted by campbelson
    the light that a fire produces dissipates... I would think sun light does also, unless it behaves differently in space or in certain space environments? How can it travel forever as someone stated above?
    If you change the channel on your TV to one that's not tuned, 1% of the static you see is "stretched" gamma radiation from the creation of atoms 13.8Ga - The Big Bang. The Cosmic Microwave Background Radiation, which pervades all space.

    If there's nothing to watch, you can always watch the birth of the universe!
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  14. #13 Big Bang, sun light... and? 
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    If you change the channel on your TV to one that's not tuned, 1% of the static you see is "stretched" gamma radiation from the creation of atoms 13.8Ga - The Big Bang. The Cosmic Microwave Background Radiation, which pervades all space.

    If there's nothing to watch, you can always watch the birth of the universe!
    Interesting, but whats the relation with the sun light we are talking about?\
    Are there not many suns in the universe? and does sunlight has anything to do with the birth of the universe, the so called big bang... In any case, my previous question remains, knowing that we are not talking about radiation per se but light... and what makes it visible for some distance only.
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  15. #14 Re: Big Bang, sun light... and? 
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    Quote Originally Posted by campbelson
    If you change the channel on your TV to one that's not tuned, 1% of the static you see is "stretched" gamma radiation from the creation of atoms 13.8Ga - The Big Bang. The Cosmic Microwave Background Radiation, which pervades all space.

    If there's nothing to watch, you can always watch the birth of the universe!
    Interesting, but whats the relation with the sun light we are talking about?\
    Are there not many suns in the universe? and does sunlight has anything to do with the birth of the universe, the so called big bang... In any case, my previous question remains, knowing that we are not talking about radiation per se but light... and what makes it visible for some distance only.
    We can see Galaxies which are billions of light years away.

    A photon can travel forever hypothetically in an ideal vacuum because it's got nothing to interact with, it won't lose energy. Space is not an ideal vacuum and there's dust and gas, which effects light.

    The intensity of light from a point source is inversely proportional to the square of the distance from the source.
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  16. #15  
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    Quote Originally Posted by campbelson
    the light that a fire produces dissipates... I would think sun light does also, unless it behaves differently in space or in certain space environments? How can it travel forever as someone stated above?

    All light is photons. Photons are distinguished only by frequency.

    Photons travel forever at a fixed speed, c, unless and until they collide with another particle and are absorbed.

    That applies to sunlight, fire light, light from a light bulb, infrared heat radiation and any other frequency of light.
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  17. #16  
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    Light is just energy and it cant be destroyed and hence it just wont lose itself in vaccuum. Even if it encounters a black hole and is trapped the energy just changes from one form to another
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