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











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?






acoustics earth planets geophysics







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
    2 days ago






  • 4




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










  • 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
    2 days ago















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?






acoustics earth planets geophysics







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
    2 days ago






  • 4




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










  • 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
    2 days ago













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?






acoustics earth planets geophysics







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




acoustics earth planets geophysics






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited 2 days ago









Qmechanic♦

99.9k121781120




99.9k121781120










asked 2 days ago









LiNKeR

344




344












  • 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
    2 days ago






  • 4




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










  • 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
    2 days ago


















  • 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
    2 days ago






  • 4




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










  • 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
    2 days ago
















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
2 days ago




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
2 days ago




4




4




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




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












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
2 days ago




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
2 days ago










1 Answer
1






active

oldest

votes

















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





















    Your Answer





    StackExchange.ifUsing("editor", function () {
    return StackExchange.using("mathjaxEditing", function () {
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    });
    });
    }, "mathjax-editing");

    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "151"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    convertImagesToLinks: false,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: null,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














     

    draft saved


    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f443500%2fhow-do-we-know-the-earths-core-is-molten-with-seismology%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    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 2 days ago









        Rob Jeffries

        67.3k7132228




        67.3k7132228






























             

            draft saved


            draft discarded



















































             


            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f443500%2fhow-do-we-know-the-earths-core-is-molten-with-seismology%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            -

            Popular posts from this blog

            Ellipse (mathématiques)

            Image
            Pour les articles homonymes, voir Ellipse. L'ellipse est le lieu des points dont la somme des distances à deux points fixes, dits foyers, est constante. Section du cône ou projection du cercle. En géométrie, une ellipse est une courbe plane fermée obtenue par l’intersection d’un cône de révolution avec un plan, à condition que celui-ci coupe l'axe de rotation du cône ou du cylindre : c'est une conique d'excentricité strictement comprise entre 0 et 1. On peut également la définir comme le lieu des points dont la somme des distances à deux points fixes, dits foyers, est constante (sa construction par la méthode du jardinier est très simple). Dans la vie courante, l’ellipse est la forme qu'on perçoit en regardant un cercle en perspective, ou la figure formée par l’ombre d'un disque sur une surface plane. On retrouve aussi, en première approximation [ 1 ] , des ellipses dans les trajectoires des corps célestes (planètes, comètes ou satellites arti...
            Read more

            Quarter-circle Tiles

            Image
            up vote 0 down vote favorite I have $99$ identical square tiles, each with a quarter-circle drawn on it like this: [asy] size(1.5cm); draw(Arc((2,0),1,90,180),red+1); draw((0,0)--(2,0)--(2,2)--(0,2)--(0,0)); [/asy] When I arrange the tiles in a $9times 11$ rectangular grid, each with a random orientation, what is the expected value of the number of full circles I form? I think this problem has to do with finding the chance any given 2x2 square has a circle, but I can't find it. expected-value share | cite | improve this question asked Nov 20 at 15:03 6minecraftninja 1 2 ...
            Read more

            Mont Emei

            Image
            Mont Emei.mw-parser-output .entete.map{background-image:url("//upload.wikimedia.org/wikipedia/commons/7/7a/Picto_infobox_map.png")} Vue du sommet Wanfo du mont Emei Géographie Altitude 3 099  m , Wanfo Coordonnées 29° 31′ 11″ nord, 103° 19′ 57″ est Administration Pays   Chine Province Sichuan Ville-préfecture Leshan Géolocalisation sur la carte : Sichuan Mont Emei Géolocalisation sur la carte : Chine Mont Emei modifier   Paysage panoramique du mont Emei, incluant le paysage panoramique du grand Bouddha de Leshan *   Patrimoine mondial de l'UNESCO Passerelle en bois sur le versant ouest Pays   Chine Subdivision Sichuan Type Mixte Critères (iv) (vi) (x) Superficie 15 400 ha Numéro d’identification 779 Zone géographique Asie et Pacifique  ** Année d’inscription 1996 (20 e session) * Descriptif officiel UNESCO ** Classification géog...
            Read more