How do we know the Earth's core is Molten with Seismology?












7














My current knowledge about how the core of the earth was discovered is the observation made from non returning/reflecting sonar signal when sent to deeper depths through the earth's crust/mantle. How was it inferred that the the core was molten?










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  • It is currently thought that there exists an outer core and an inner core. The outer core is molten, but the inner core is thought to be solid. The methods used to determine this are basically described in Ron Jeffries' answer.
    – StephenG
    Nov 26 '18 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 '18 at 1:52










  • When you say 'sonar signals' are 'sent', that suggests that artificial signals are sent using some kind of seismologist's apparatus. That is certainly not the case -- such signals would never make it down that far. Instead, the vibrations caused by earthquakes are monitored by different stations around the world.
    – TonyK
    Nov 27 '18 at 2:19
















7














My current knowledge about how the core of the earth was discovered is the observation made from non returning/reflecting sonar signal when sent to deeper depths through the earth's crust/mantle. How was it inferred that the the core was molten?










share|cite|improve this question
























  • It is currently thought that there exists an outer core and an inner core. The outer core is molten, but the inner core is thought to be solid. The methods used to determine this are basically described in Ron Jeffries' answer.
    – StephenG
    Nov 26 '18 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 '18 at 1:52










  • When you say 'sonar signals' are 'sent', that suggests that artificial signals are sent using some kind of seismologist's apparatus. That is certainly not the case -- such signals would never make it down that far. Instead, the vibrations caused by earthquakes are monitored by different stations around the world.
    – TonyK
    Nov 27 '18 at 2:19














7












7








7







My current knowledge about how the core of the earth was discovered is the observation made from non returning/reflecting sonar signal when sent to deeper depths through the earth's crust/mantle. How was it inferred that the the core was molten?










share|cite|improve this question















My current knowledge about how the core of the earth was discovered is the observation made from non returning/reflecting sonar signal when sent to deeper depths through the earth's crust/mantle. How was it inferred that the the core was molten?







acoustics earth planets geophysics






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edited Nov 26 '18 at 20:28









Qmechanic

101k121831151




101k121831151










asked Nov 26 '18 at 20:08









LiNKeR

445




445












  • It is currently thought that there exists an outer core and an inner core. The outer core is molten, but the inner core is thought to be solid. The methods used to determine this are basically described in Ron Jeffries' answer.
    – StephenG
    Nov 26 '18 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 '18 at 1:52










  • When you say 'sonar signals' are 'sent', that suggests that artificial signals are sent using some kind of seismologist's apparatus. That is certainly not the case -- such signals would never make it down that far. Instead, the vibrations caused by earthquakes are monitored by different stations around the world.
    – TonyK
    Nov 27 '18 at 2:19


















  • It is currently thought that there exists an outer core and an inner core. The outer core is molten, but the inner core is thought to be solid. The methods used to determine this are basically described in Ron Jeffries' answer.
    – StephenG
    Nov 26 '18 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 '18 at 1:52










  • When you say 'sonar signals' are 'sent', that suggests that artificial signals are sent using some kind of seismologist's apparatus. That is certainly not the case -- such signals would never make it down that far. Instead, the vibrations caused by earthquakes are monitored by different stations around the world.
    – TonyK
    Nov 27 '18 at 2:19
















It is currently thought that there exists an outer core and an inner core. The outer core is molten, but the inner core is thought to be solid. The methods used to determine this are basically described in Ron Jeffries' answer.
– StephenG
Nov 26 '18 at 22:37




It is currently thought that there exists an outer core and an inner core. The outer core is molten, but the inner core is thought to be solid. The methods used to determine this are basically described in Ron Jeffries' answer.
– StephenG
Nov 26 '18 at 22:37




4




4




BTW: I (with help) just landed a seismometer on Mars a few hours ago.
– JEB
Nov 27 '18 at 1:52




BTW: I (with help) just landed a seismometer on Mars a few hours ago.
– JEB
Nov 27 '18 at 1:52












When you say 'sonar signals' are 'sent', that suggests that artificial signals are sent using some kind of seismologist's apparatus. That is certainly not the case -- such signals would never make it down that far. Instead, the vibrations caused by earthquakes are monitored by different stations around the world.
– TonyK
Nov 27 '18 at 2:19




When you say 'sonar signals' are 'sent', that suggests that artificial signals are sent using some kind of seismologist's apparatus. That is certainly not the case -- such signals would never make it down that far. Instead, the vibrations caused by earthquakes are monitored by different stations around the world.
– TonyK
Nov 27 '18 at 2:19










1 Answer
1






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oldest

votes


















13














There are basically two types of waves - shear (s) waves and primary (p) compression waves.



P waves can travel through solids and liquids but s waves do not travel in fluids.



That p waves, but not s waves, are detected from events occurring on the other side of the globe tells you that there is fluid in the way.



This is the basic picture; it is complicated/enhanced by refraction and dispersion of the waves.






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    1 Answer
    1






    active

    oldest

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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    13














    There are basically two types of waves - shear (s) waves and primary (p) compression waves.



    P waves can travel through solids and liquids but s waves do not travel in fluids.



    That p waves, but not s waves, are detected from events occurring on the other side of the globe tells you that there is fluid in the way.



    This is the basic picture; it is complicated/enhanced by refraction and dispersion of the waves.






    share|cite|improve this answer


























      13














      There are basically two types of waves - shear (s) waves and primary (p) compression waves.



      P waves can travel through solids and liquids but s waves do not travel in fluids.



      That p waves, but not s waves, are detected from events occurring on the other side of the globe tells you that there is fluid in the way.



      This is the basic picture; it is complicated/enhanced by refraction and dispersion of the waves.






      share|cite|improve this answer
























        13












        13








        13






        There are basically two types of waves - shear (s) waves and primary (p) compression waves.



        P waves can travel through solids and liquids but s waves do not travel in fluids.



        That p waves, but not s waves, are detected from events occurring on the other side of the globe tells you that there is fluid in the way.



        This is the basic picture; it is complicated/enhanced by refraction and dispersion of the waves.






        share|cite|improve this answer












        There are basically two types of waves - shear (s) waves and primary (p) compression waves.



        P waves can travel through solids and liquids but s waves do not travel in fluids.



        That p waves, but not s waves, are detected from events occurring on the other side of the globe tells you that there is fluid in the way.



        This is the basic picture; it is complicated/enhanced by refraction and dispersion of the waves.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 26 '18 at 20:24









        Rob Jeffries

        67.8k7135228




        67.8k7135228






























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