Are photons affected by Earth's gravity?

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Just wondering if the Earth's gravity affects the photons ............ We can obviously think about equivalent mass of photons by using de broglie relation and then use it to calculate force of gravitational interaction. But still this thought is very revolting. Help would be appreciated ?










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    Light paths are bent by gravitational fields. So the answer is yes they are affected. A different question is whether the affect is meaningful or measurable with current instruments. There is nothing special about the Earth as compared to a star or other source other than strength.
    – ggcg
    1 hour ago














up vote
3
down vote

favorite












Just wondering if the Earth's gravity affects the photons ............ We can obviously think about equivalent mass of photons by using de broglie relation and then use it to calculate force of gravitational interaction. But still this thought is very revolting. Help would be appreciated ?










share|cite|improve this question







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Aditya Garg is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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  • 3




    Light paths are bent by gravitational fields. So the answer is yes they are affected. A different question is whether the affect is meaningful or measurable with current instruments. There is nothing special about the Earth as compared to a star or other source other than strength.
    – ggcg
    1 hour ago












up vote
3
down vote

favorite









up vote
3
down vote

favorite











Just wondering if the Earth's gravity affects the photons ............ We can obviously think about equivalent mass of photons by using de broglie relation and then use it to calculate force of gravitational interaction. But still this thought is very revolting. Help would be appreciated ?










share|cite|improve this question







New contributor




Aditya Garg is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











Just wondering if the Earth's gravity affects the photons ............ We can obviously think about equivalent mass of photons by using de broglie relation and then use it to calculate force of gravitational interaction. But still this thought is very revolting. Help would be appreciated ?







gravity interference geometric-optics wave-particle-duality






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  • 3




    Light paths are bent by gravitational fields. So the answer is yes they are affected. A different question is whether the affect is meaningful or measurable with current instruments. There is nothing special about the Earth as compared to a star or other source other than strength.
    – ggcg
    1 hour ago












  • 3




    Light paths are bent by gravitational fields. So the answer is yes they are affected. A different question is whether the affect is meaningful or measurable with current instruments. There is nothing special about the Earth as compared to a star or other source other than strength.
    – ggcg
    1 hour ago







3




3




Light paths are bent by gravitational fields. So the answer is yes they are affected. A different question is whether the affect is meaningful or measurable with current instruments. There is nothing special about the Earth as compared to a star or other source other than strength.
– ggcg
1 hour ago




Light paths are bent by gravitational fields. So the answer is yes they are affected. A different question is whether the affect is meaningful or measurable with current instruments. There is nothing special about the Earth as compared to a star or other source other than strength.
– ggcg
1 hour ago










2 Answers
2






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4
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accepted










Yep. Gravity effects photons. Here's a thought experiment from Einstein:



Suppose you have a block having mass $m$ at the top of a tower. Drop it.



It picks up speed due to gravity as it falls, gaining kinetic energy.



Now suppose there's some super efficient means of converting mass to energy at the bottom of the tower and the newly created photons were fired back at the source point. Once they arrived at the source point, we reconverted the photons back to mass and started over again.



If we assume no loss of energy on the way up, then we have the makings of a perpetual motion machine.



We have to lose energy on the way up which means we have a reduction in frequency. Because the product of frequency with wavelength is a constant, the speed of light, the reduction in one implies the increase in the other. So the wavelength of the photon increases as it rises back to the top of the tower. This is a Red Shift.



More generally, gravity distorts space-time. Space itself is curved. Just as the shortest distance between two points on a globe is not a straight line, the shortest distance paths between two points in curved space time, i.e. in a gravitational field, is also not a straight line. The lines do not exist. So the path's of photons must change.






share|cite|improve this answer





























    up vote
    3
    down vote













    I think you're right to be uncomfortable in calculating a "mass" of a photon. The true reason that light is deflected around any massive object is because all massive objects distort spacetime.



    You've probably heard the phrase "Light travels in straight lines", and we can apply this line to the bending of spacetime too. Without too much mathematical detail, we can imagine what would happen to a "straight line" on a flat piece of spacetime when the spacetime itself is bent. The classic demonstration is a trampoline sheet with heavy balls on it. Anything trying to zip past a heavy ball (including light) is bent - see this popular YouTube video.



    (Using more precise terminology, light follows what are called "null geodesics" in spacetime. In flat spacetime (with no gravity) these are just straight lines. However in curved spacetime, they are no longer straight lines, and indeed massive objects bend the space around them sufficiently to bend the light's path).






    share|cite|improve this answer




















    • It is more complete to say that any nonzero energy-momentum tensor distorts spacetime, not just nonzero mass. For instance, photons affect other photons gravitationally.
      – Avantgarde
      37 mins ago










    Your Answer





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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    4
    down vote



    accepted










    Yep. Gravity effects photons. Here's a thought experiment from Einstein:



    Suppose you have a block having mass $m$ at the top of a tower. Drop it.



    It picks up speed due to gravity as it falls, gaining kinetic energy.



    Now suppose there's some super efficient means of converting mass to energy at the bottom of the tower and the newly created photons were fired back at the source point. Once they arrived at the source point, we reconverted the photons back to mass and started over again.



    If we assume no loss of energy on the way up, then we have the makings of a perpetual motion machine.



    We have to lose energy on the way up which means we have a reduction in frequency. Because the product of frequency with wavelength is a constant, the speed of light, the reduction in one implies the increase in the other. So the wavelength of the photon increases as it rises back to the top of the tower. This is a Red Shift.



    More generally, gravity distorts space-time. Space itself is curved. Just as the shortest distance between two points on a globe is not a straight line, the shortest distance paths between two points in curved space time, i.e. in a gravitational field, is also not a straight line. The lines do not exist. So the path's of photons must change.






    share|cite|improve this answer


























      up vote
      4
      down vote



      accepted










      Yep. Gravity effects photons. Here's a thought experiment from Einstein:



      Suppose you have a block having mass $m$ at the top of a tower. Drop it.



      It picks up speed due to gravity as it falls, gaining kinetic energy.



      Now suppose there's some super efficient means of converting mass to energy at the bottom of the tower and the newly created photons were fired back at the source point. Once they arrived at the source point, we reconverted the photons back to mass and started over again.



      If we assume no loss of energy on the way up, then we have the makings of a perpetual motion machine.



      We have to lose energy on the way up which means we have a reduction in frequency. Because the product of frequency with wavelength is a constant, the speed of light, the reduction in one implies the increase in the other. So the wavelength of the photon increases as it rises back to the top of the tower. This is a Red Shift.



      More generally, gravity distorts space-time. Space itself is curved. Just as the shortest distance between two points on a globe is not a straight line, the shortest distance paths between two points in curved space time, i.e. in a gravitational field, is also not a straight line. The lines do not exist. So the path's of photons must change.






      share|cite|improve this answer
























        up vote
        4
        down vote



        accepted







        up vote
        4
        down vote



        accepted






        Yep. Gravity effects photons. Here's a thought experiment from Einstein:



        Suppose you have a block having mass $m$ at the top of a tower. Drop it.



        It picks up speed due to gravity as it falls, gaining kinetic energy.



        Now suppose there's some super efficient means of converting mass to energy at the bottom of the tower and the newly created photons were fired back at the source point. Once they arrived at the source point, we reconverted the photons back to mass and started over again.



        If we assume no loss of energy on the way up, then we have the makings of a perpetual motion machine.



        We have to lose energy on the way up which means we have a reduction in frequency. Because the product of frequency with wavelength is a constant, the speed of light, the reduction in one implies the increase in the other. So the wavelength of the photon increases as it rises back to the top of the tower. This is a Red Shift.



        More generally, gravity distorts space-time. Space itself is curved. Just as the shortest distance between two points on a globe is not a straight line, the shortest distance paths between two points in curved space time, i.e. in a gravitational field, is also not a straight line. The lines do not exist. So the path's of photons must change.






        share|cite|improve this answer














        Yep. Gravity effects photons. Here's a thought experiment from Einstein:



        Suppose you have a block having mass $m$ at the top of a tower. Drop it.



        It picks up speed due to gravity as it falls, gaining kinetic energy.



        Now suppose there's some super efficient means of converting mass to energy at the bottom of the tower and the newly created photons were fired back at the source point. Once they arrived at the source point, we reconverted the photons back to mass and started over again.



        If we assume no loss of energy on the way up, then we have the makings of a perpetual motion machine.



        We have to lose energy on the way up which means we have a reduction in frequency. Because the product of frequency with wavelength is a constant, the speed of light, the reduction in one implies the increase in the other. So the wavelength of the photon increases as it rises back to the top of the tower. This is a Red Shift.



        More generally, gravity distorts space-time. Space itself is curved. Just as the shortest distance between two points on a globe is not a straight line, the shortest distance paths between two points in curved space time, i.e. in a gravitational field, is also not a straight line. The lines do not exist. So the path's of photons must change.







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited 1 hour ago

























        answered 1 hour ago









        R. Romero

        2116




        2116




















            up vote
            3
            down vote













            I think you're right to be uncomfortable in calculating a "mass" of a photon. The true reason that light is deflected around any massive object is because all massive objects distort spacetime.



            You've probably heard the phrase "Light travels in straight lines", and we can apply this line to the bending of spacetime too. Without too much mathematical detail, we can imagine what would happen to a "straight line" on a flat piece of spacetime when the spacetime itself is bent. The classic demonstration is a trampoline sheet with heavy balls on it. Anything trying to zip past a heavy ball (including light) is bent - see this popular YouTube video.



            (Using more precise terminology, light follows what are called "null geodesics" in spacetime. In flat spacetime (with no gravity) these are just straight lines. However in curved spacetime, they are no longer straight lines, and indeed massive objects bend the space around them sufficiently to bend the light's path).






            share|cite|improve this answer




















            • It is more complete to say that any nonzero energy-momentum tensor distorts spacetime, not just nonzero mass. For instance, photons affect other photons gravitationally.
              – Avantgarde
              37 mins ago














            up vote
            3
            down vote













            I think you're right to be uncomfortable in calculating a "mass" of a photon. The true reason that light is deflected around any massive object is because all massive objects distort spacetime.



            You've probably heard the phrase "Light travels in straight lines", and we can apply this line to the bending of spacetime too. Without too much mathematical detail, we can imagine what would happen to a "straight line" on a flat piece of spacetime when the spacetime itself is bent. The classic demonstration is a trampoline sheet with heavy balls on it. Anything trying to zip past a heavy ball (including light) is bent - see this popular YouTube video.



            (Using more precise terminology, light follows what are called "null geodesics" in spacetime. In flat spacetime (with no gravity) these are just straight lines. However in curved spacetime, they are no longer straight lines, and indeed massive objects bend the space around them sufficiently to bend the light's path).






            share|cite|improve this answer




















            • It is more complete to say that any nonzero energy-momentum tensor distorts spacetime, not just nonzero mass. For instance, photons affect other photons gravitationally.
              – Avantgarde
              37 mins ago












            up vote
            3
            down vote










            up vote
            3
            down vote









            I think you're right to be uncomfortable in calculating a "mass" of a photon. The true reason that light is deflected around any massive object is because all massive objects distort spacetime.



            You've probably heard the phrase "Light travels in straight lines", and we can apply this line to the bending of spacetime too. Without too much mathematical detail, we can imagine what would happen to a "straight line" on a flat piece of spacetime when the spacetime itself is bent. The classic demonstration is a trampoline sheet with heavy balls on it. Anything trying to zip past a heavy ball (including light) is bent - see this popular YouTube video.



            (Using more precise terminology, light follows what are called "null geodesics" in spacetime. In flat spacetime (with no gravity) these are just straight lines. However in curved spacetime, they are no longer straight lines, and indeed massive objects bend the space around them sufficiently to bend the light's path).






            share|cite|improve this answer












            I think you're right to be uncomfortable in calculating a "mass" of a photon. The true reason that light is deflected around any massive object is because all massive objects distort spacetime.



            You've probably heard the phrase "Light travels in straight lines", and we can apply this line to the bending of spacetime too. Without too much mathematical detail, we can imagine what would happen to a "straight line" on a flat piece of spacetime when the spacetime itself is bent. The classic demonstration is a trampoline sheet with heavy balls on it. Anything trying to zip past a heavy ball (including light) is bent - see this popular YouTube video.



            (Using more precise terminology, light follows what are called "null geodesics" in spacetime. In flat spacetime (with no gravity) these are just straight lines. However in curved spacetime, they are no longer straight lines, and indeed massive objects bend the space around them sufficiently to bend the light's path).







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered 1 hour ago









            Garf

            1,182217




            1,182217











            • It is more complete to say that any nonzero energy-momentum tensor distorts spacetime, not just nonzero mass. For instance, photons affect other photons gravitationally.
              – Avantgarde
              37 mins ago
















            • It is more complete to say that any nonzero energy-momentum tensor distorts spacetime, not just nonzero mass. For instance, photons affect other photons gravitationally.
              – Avantgarde
              37 mins ago















            It is more complete to say that any nonzero energy-momentum tensor distorts spacetime, not just nonzero mass. For instance, photons affect other photons gravitationally.
            – Avantgarde
            37 mins ago




            It is more complete to say that any nonzero energy-momentum tensor distorts spacetime, not just nonzero mass. For instance, photons affect other photons gravitationally.
            – Avantgarde
            37 mins ago










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