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











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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 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 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 at 2:19















up vote
6
down vote

favorite












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 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 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 at 2:19













up vote
6
down vote

favorite









up vote
6
down vote

favorite











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 at 20:28









Qmechanic

100k121801128




100k121801128










asked Nov 26 at 20:08









LiNKeR

394




394












  • 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 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 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 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 at 22:37






  • 4




    BTW: I (with help) just landed a seismometer on Mars a few hours ago.
    – JEB
    Nov 27 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 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 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 at 22:37




4




4




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




BTW: I (with help) just landed a seismometer on Mars a few hours ago.
– JEB
Nov 27 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 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 at 2:19










1 Answer
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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
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    active

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    1 Answer
    1






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    active

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    up vote
    11
    down vote













    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

























      up vote
      11
      down vote













      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























        up vote
        11
        down vote










        up vote
        11
        down vote









        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 at 20:24









        Rob Jeffries

        67.5k7132228




        67.5k7132228






























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