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<h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Gravitationsfeld</span></h1>
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<div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="de" dir="ltr"><div class="mw-content-ltr mw-parser-output" lang="de" dir="ltr"><p>In der <a href="Klassische_Mechanik" title="Klassische Mechanik">klassischen Mechanik</a> ist das <b>Gravitationsfeld</b> (auch <b>Schwerkraftfeld</b>) das <a href="Kraftfeld" title="Kraftfeld">Kraftfeld</a>, das durch die <a href="Gravitation" title="Gravitation">Gravitation</a> von <a href="Masse_(Physik)" title="Masse (Physik)">Massen</a> hervorgerufen wird. Die <a href="Feldst%C3%A4rke" title="Feldstärke">Feldstärke</a> des Gravitationsfeldes gibt für jeden Ort den durch Gravitation verursachten Teil der <a href="Fallbeschleunigung" class="mw-redirect" title="Fallbeschleunigung">Fallbeschleunigung</a> <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
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<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/8aad928c73fda5199478a151663f0ce3a57a8027.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.174ex; height:2.676ex;" alt="{\displaystyle {\vec {g}}}" loading="lazy"></span> an. Sie kann mithilfe des Newtonschen <a href="Gravitationsgesetz" class="mw-redirect" title="Gravitationsgesetz">Gravitationsgesetzes</a> aus der räumlichen Verteilung der Massen berechnet werden.
</p><p>In rotierenden Bezugssystemen, wie dem mit der Erde verbundenen, wird das Gravitationsfeld (Schwer<b>kraft</b>feld) unterschieden vom <a href="Schwerefeld" title="Schwerefeld">Schwerefeld</a>, in dem zusätzlich auch die <a href="Zentrifugalkraft" title="Zentrifugalkraft">Zentrifugalbeschleunigung</a> berücksichtigt wird.
</p><p>Die <a href="Einsteinsche_Feldgleichungen" title="Einsteinsche Feldgleichungen">Einsteinschen Feldgleichungen</a> der <a href="Allgemeine_Relativit%C3%A4tstheorie" title="Allgemeine Relativitätstheorie">Allgemeinen Relativitätstheorie</a> beschreiben die Gravitation nicht mehr als Kraftfeld, sondern als <a href="Raumkr%C3%BCmmung" title="Raumkrümmung">Krümmung der Raumzeit</a>.
</p><p>Zur Veranschaulichung der Wirkung eines Gravitationsfeldes kann der <i>Potentialtrichter</i> dienen, in dem Kugeln oder Münzen auf einer dreidimensionalen <a href="Trichter" title="Trichter">Trichterfläche</a> rollen und dabei eine <a href="Umlaufbahn" title="Umlaufbahn">Umlaufbahn</a> um die Trichterachse simulieren.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Die Gravitationskraft wirkt im Potentialtrichter auch indirekt: Die zur Mitte <a href="Schiefe_Ebene" title="Schiefe Ebene">abfallende Trichterwandung</a> teilt sie in eine horizontale und vertikale Komponente und lässt die Kugeln zum Mittelpunkt des Trichters hin rollen, wenn die geschwindigkeitsabhängige Zentrifugalkraft nicht mehr ausreicht, die Kugeln auf der äußeren Bahn zu halten.
</p>
<div class="mw-heading mw-heading2"><h2 id="Potential_und_Feld">Potential und Feld</h2></div>
<div class="hauptartikel" role="navigation"><span class="hauptartikel-pfeil" title="siehe" aria-hidden="true" role="presentation">→ </span><i><span class="hauptartikel-text">Hauptartikel</span>: <a href="Potential_(Physik)" title="Potential (Physik)">Potential</a> und <a href="Feld_(Physik)" title="Feld (Physik)">Feld</a></i></div>
<p>Das zum Gravitationsfeld gehörende Potential heißt <b>Gravitationspotential</b>. Sein Wert <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Phi ({\vec {r}})}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
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<mo stretchy="false">)</mo>
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<annotation encoding="application/x-tex">{\displaystyle \Phi ({\vec {r}})}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/2cfea3f7427562ff5dc633ca253c311a395c34b2.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:4.71ex; height:2.843ex;" alt="{\displaystyle \Phi ({\vec {r}})}" loading="lazy"></span> am Ort <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {r}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
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<mo stretchy="false">→<!-- → --></mo>
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</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {r}}}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/6aec3c9ce13b53e9e24c98e7cce4212627884c91.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.223ex; height:2.343ex;" alt="{\displaystyle {\vec {r}}}" loading="lazy"></span> lässt sich bei bekannter <a href="Massendichte" class="mw-redirect" title="Massendichte">Massendichte</a> <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \rho ({\vec {r}})}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>ρ<!-- ρ --></mi>
<mo stretchy="false">(</mo>
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<mo stretchy="false">)</mo>
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<annotation encoding="application/x-tex">{\displaystyle \rho ({\vec {r}})}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/c80c262b5476b043478d88adb73498aac8b80de9.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:4.234ex; height:2.843ex;" alt="{\displaystyle \rho ({\vec {r}})}" loading="lazy"></span> durch Lösen der <a href="Poisson-Gleichung" title="Poisson-Gleichung">Poisson-Gleichung</a> bestimmen
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Delta \Phi ({\vec {r}})=4\pi G\rho ({\vec {r}})}">
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<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">Δ<!-- Δ --></mi>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
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<mo stretchy="false">)</mo>
<mo>=</mo>
<mn>4</mn>
<mi>π<!-- π --></mi>
<mi>G</mi>
<mi>ρ<!-- ρ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
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<mo stretchy="false">)</mo>
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<annotation encoding="application/x-tex">{\displaystyle \Delta \Phi ({\vec {r}})=4\pi G\rho ({\vec {r}})}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/99be281260edfaa8c7b583bf4f3d403077f2cf10.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:18.3ex; height:2.843ex;" alt="{\displaystyle \Delta \Phi ({\vec {r}})=4\pi G\rho ({\vec {r}})}" loading="lazy"></span>,</dd></dl>
<p>wobei <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle G}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>G</mi>
</mstyle>
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<annotation encoding="application/x-tex">{\displaystyle G}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f5f3c8921a3b352de45446a6789b104458c9f90b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.827ex; height:2.176ex;" alt="{\displaystyle G}" loading="lazy"></span> die <a href="Gravitationskonstante" title="Gravitationskonstante">Gravitationskonstante</a> und <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Delta }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">Δ<!-- Δ --></mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \Delta }</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/32769037c408874e1890f77554c65f39c523ebe2.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.936ex; height:2.176ex;" alt="{\displaystyle \Delta }" loading="lazy"></span> der <a href="Laplace-Operator" title="Laplace-Operator">Laplace-Operator</a> ist. So beträgt das Potential um einen näherungsweise punktförmigen oder <a href="Radialsymmetrisch" class="mw-redirect" title="Radialsymmetrisch">radialsymmetrischen</a> Körper der Masse <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>M</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle M}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f82cade9898ced02fdd08712e5f0c0151758a0dd.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.442ex; height:2.176ex;" alt="{\displaystyle M}" loading="lazy"></span> beispielsweise
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Phi (r)=-{\frac {GM}{r}}\ ({}+\Phi _{\infty })}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
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<mo>=</mo>
<mo>−<!-- − --></mo>
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<mtext> </mtext>
<mo stretchy="false">(</mo>
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<mrow class="MJX-TeXAtom-ORD">
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<mo stretchy="false">)</mo>
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<annotation encoding="application/x-tex">{\displaystyle \Phi (r)=-{\frac {GM}{r}}\ ({}+\Phi _{\infty })}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/d0ac267d97d2e41c5d3c6f02a32955c81125be34.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:23.331ex; height:5.343ex;" alt="{\displaystyle \Phi (r)=-{\frac {GM}{r}}\ ({}+\Phi _{\infty })}" loading="lazy"></span>.</dd></dl>
<p>Hierbei ist <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Phi _{\infty }}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">∞<!-- ∞ --></mi>
</mrow>
</msub>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \Phi _{\infty }}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/90fa9102d704000b296d6f6748392f8ef5a47cb4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.553ex; height:2.509ex;" alt="{\displaystyle \Phi _{\infty }}" loading="lazy"></span> das Potential im Unendlichen. Es ist eine frei wählbare Integrationskonstante und wird üblicherweise willkürlich auf Null gesetzt.
</p><p>Multipliziert man das Potential mit der Masse eines Körpers <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>m</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle m}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0a07d98bb302f3856cbabc47b2b9016692e3f7bc.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.04ex; height:1.676ex;" alt="{\displaystyle m}" loading="lazy"></span>, so erhält man seine potentielle Energie
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V({\vec {r}})=m\,\Phi ({\vec {r}})}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>V</mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
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<mo stretchy="false">)</mo>
<mo>=</mo>
<mi>m</mi>
<mspace width="thinmathspace"></mspace>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
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<mi>r</mi>
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<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle V({\vec {r}})=m\,\Phi ({\vec {r}})}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0e79ba99932ef35cb92480f600623763e409a81e.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.056ex; height:2.843ex;" alt="{\displaystyle V({\vec {r}})=m\,\Phi ({\vec {r}})}" loading="lazy"></span>.</dd></dl>
<p>Das Gravitationsfeld <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
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<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
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</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/8aad928c73fda5199478a151663f0ce3a57a8027.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.174ex; height:2.676ex;" alt="{\displaystyle {\vec {g}}}" loading="lazy"></span> lässt sich als <a href="Gradientenfeld" title="Gradientenfeld">Gradientenfeld</a> des Gravitationspotentials <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Phi }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">Φ<!-- Φ --></mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \Phi }</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/aed80a2011a3912b028ba32a52dfa57165455f24.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.678ex; height:2.176ex;" alt="{\displaystyle \Phi }" loading="lazy"></span> schreiben:
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}({\vec {r}})=-\nabla \Phi ({\vec {r}})}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mi mathvariant="normal">∇<!-- ∇ --></mi>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}({\vec {r}})=-\nabla \Phi ({\vec {r}})}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/9e271e5e69ee23c67db9873acce2d634da8f736f.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.759ex; height:2.843ex;" alt="{\displaystyle {\vec {g}}({\vec {r}})=-\nabla \Phi ({\vec {r}})}" loading="lazy"></span>.</dd></dl>
<p>Die vom Feld erzeugte Kraft <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {F}}_{\mathrm {G} }}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>F</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">G</mi>
</mrow>
</mrow>
</msub>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {F}}_{\mathrm {G} }}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/bec9f04ea642e77c660208f64c14318a56d0dded.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.293ex; height:3.176ex;" alt="{\displaystyle {\vec {F}}_{\mathrm {G} }}" loading="lazy"></span> auf einen Körper der Masse <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>m</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle m}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0a07d98bb302f3856cbabc47b2b9016692e3f7bc.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.04ex; height:1.676ex;" alt="{\displaystyle m}" loading="lazy"></span> ist dann
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {F}}_{\mathrm {G} }({\vec {r}})=m\,{\vec {g}}({\vec {r}})}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>F</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">G</mi>
</mrow>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mi>m</mi>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {F}}_{\mathrm {G} }({\vec {r}})=m\,{\vec {g}}({\vec {r}})}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/29d9eef811876cdf26b85533f099dc9594a32d42.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:16.058ex; height:3.343ex;" alt="{\displaystyle {\vec {F}}_{\mathrm {G} }({\vec {r}})=m\,{\vec {g}}({\vec {r}})}" loading="lazy"></span>.</dd></dl>
<div class="mw-heading mw-heading2"><h2 id="Feldstärke"><span id="Feldst.C3.A4rke"></span>Feldstärke</h2></div>
<div class="hauptartikel" role="navigation"><span class="hauptartikel-pfeil" title="siehe" aria-hidden="true" role="presentation">→ </span><i><span class="hauptartikel-text">Hauptartikel</span>: <a href="Feldst%C3%A4rke" title="Feldstärke">Feldstärke</a></i></div>
<p>Die <b>Gravitationsfeldstärke</b> gibt direkt die <b>Gravitationsbeschleunigung</b> <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/8aad928c73fda5199478a151663f0ce3a57a8027.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.174ex; height:2.676ex;" alt="{\displaystyle {\vec {g}}}" loading="lazy"></span> an und wird oft auch mit diesem Wort bezeichnet. Sie ist unabhängig von der <a href="Probemasse" class="mw-redirect" title="Probemasse">Probemasse</a> (also der Masse des betrachteten Körpers, der sich im Gravitationsfeld befindet). Wirken keine weiteren Kräfte, so ist <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/8aad928c73fda5199478a151663f0ce3a57a8027.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.174ex; height:2.676ex;" alt="{\displaystyle {\vec {g}}}" loading="lazy"></span> die exakte <a href="Beschleunigung" title="Beschleunigung">Beschleunigung</a> einer Probemasse im Feld.
</p><p>Eine Punktmasse <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>M</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle M}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f82cade9898ced02fdd08712e5f0c0151758a0dd.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.442ex; height:2.176ex;" alt="{\displaystyle M}" loading="lazy"></span> verursacht das Potential
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Phi ({\vec {r}})=-{\frac {GM}{r}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>G</mi>
<mi>M</mi>
</mrow>
<mi>r</mi>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \Phi ({\vec {r}})=-{\frac {GM}{r}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/e1341396371f5caafd9ba2f35dc810813f5f9198.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:14.722ex; height:5.343ex;" alt="{\displaystyle \Phi ({\vec {r}})=-{\frac {GM}{r}}}" loading="lazy"></span></dd></dl>
<p>und daher das dazugehörige <a href="Zentralfeld" class="mw-redirect" title="Zentralfeld">radialsymmetrische Feld</a> mit der Feldstärke
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}({\vec {r}})=-{\frac {GM}{r^{2}}}{\hat {e}}_{r}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>G</mi>
<mi>M</mi>
</mrow>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mfrac>
</mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>e</mi>
<mo stretchy="false">^<!-- ^ --></mo>
</mover>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>r</mi>
</mrow>
</msub>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}({\vec {r}})=-{\frac {GM}{r^{2}}}{\hat {e}}_{r}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/240394a58328dec0d10b9732f39205fcc3df6be0.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; width:16.484ex; height:5.676ex;" alt="{\displaystyle {\vec {g}}({\vec {r}})=-{\frac {GM}{r^{2}}}{\hat {e}}_{r}}" loading="lazy"></span></dd></dl>
<p>Formal ähnelt diese Gleichung derjenigen für die <a href="Elektrische_Feldst%C3%A4rke" title="Elektrische Feldstärke">elektrischen Feldstärke</a> in der Umgebung einer <a href="Punktladung" title="Punktladung">Punktladung</a>. In beiden Gleichungen nimmt der Betrag der Feldstärke quadratisch mit dem Abstand ab. Das Minus drückt aus, dass Gravitationskräfte stets anziehend sind, während elektrostatische Kräfte zwischen gleichnamigen Ladungen abstoßend sind, weshalb das Minus in jener Gleichung fehlt.
</p><p>Diese Formel gilt auch für kugelsymmetrische Körper, wenn der Abstand <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>r</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle r}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0d1ecb613aa2984f0576f70f86650b7c2a132538.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.049ex; height:1.676ex;" alt="{\displaystyle r}" loading="lazy"></span> vom Mittelpunkt größer ist als sein Radius. Sie gilt näherungsweise für jeden beliebig geformten Körper, wenn <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>r</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle r}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0d1ecb613aa2984f0576f70f86650b7c2a132538.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.049ex; height:1.676ex;" alt="{\displaystyle r}" loading="lazy"></span> um <a href="Gr%C3%B6%C3%9Fenordnung" title="Größenordnung">Größenordnungen</a> größer als seine Ausdehnung ist. Befindet sich eine Probemasse <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>m</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle m}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0a07d98bb302f3856cbabc47b2b9016692e3f7bc.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.04ex; height:1.676ex;" alt="{\displaystyle m}" loading="lazy"></span> in diesem Gravitationsfeld, so ergibt sich
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle F_{\mathrm {G} }=m\,g(r)=m{\frac {GM}{r^{2}}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">G</mi>
</mrow>
</mrow>
</msub>
<mo>=</mo>
<mi>m</mi>
<mspace width="thinmathspace"></mspace>
<mi>g</mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mi>m</mi>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>G</mi>
<mi>M</mi>
</mrow>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle F_{\mathrm {G} }=m\,g(r)=m{\frac {GM}{r^{2}}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/073b0a188f6addaf7dcfff404d7e1185217a9ac2.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; width:22.761ex; height:5.676ex;" alt="{\displaystyle F_{\mathrm {G} }=m\,g(r)=m{\frac {GM}{r^{2}}}}" loading="lazy"></span>.</dd></dl>
<p>Dies entspricht dem <a href="Newtonsches_Gravitationsgesetz" title="Newtonsches Gravitationsgesetz">Newtonschen Gravitationsgesetz</a>, das den Betrag der wirkenden anziehenden Kraft zwischen den <a href="Massenschwerpunkt" class="mw-redirect" title="Massenschwerpunkt">Massenschwerpunkten</a> von <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>M</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle M}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f82cade9898ced02fdd08712e5f0c0151758a0dd.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.442ex; height:2.176ex;" alt="{\displaystyle M}" loading="lazy"></span> und <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>m</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle m}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0a07d98bb302f3856cbabc47b2b9016692e3f7bc.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.04ex; height:1.676ex;" alt="{\displaystyle m}" loading="lazy"></span> angibt, die sich im Abstand <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>r</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle r}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0d1ecb613aa2984f0576f70f86650b7c2a132538.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.049ex; height:1.676ex;" alt="{\displaystyle r}" loading="lazy"></span> befinden.
</p><p>Da jede beliebig ausgedehnte Masse in (annähernd) punktförmige Teilmassen zerlegt werden kann, lässt sich jedes Gravitationsfeld auch als Summe über viele Punktmassen darstellen:
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}({\vec {r}})=-G\sum _{i}{m_{i}}{\frac {{\vec {r}}-{\vec {r}}_{i}}{|{\vec {r}}-{\vec {r}}_{i}|^{3}}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mi>G</mi>
<munder>
<mo>∑<!-- ∑ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
</mrow>
</munder>
<mrow class="MJX-TeXAtom-ORD">
<msub>
<mi>m</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
</mrow>
</msub>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>−<!-- − --></mo>
<msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
</mrow>
</msub>
</mrow>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>−<!-- − --></mo>
<msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
</mrow>
</msub>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}({\vec {r}})=-G\sum _{i}{m_{i}}{\frac {{\vec {r}}-{\vec {r}}_{i}}{|{\vec {r}}-{\vec {r}}_{i}|^{3}}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/683ab589c554cf907844b72927eedd19ffd57543.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.005ex; width:27.179ex; height:6.509ex;" alt="{\displaystyle {\vec {g}}({\vec {r}})=-G\sum _{i}{m_{i}}{\frac {{\vec {r}}-{\vec {r}}_{i}}{|{\vec {r}}-{\vec {r}}_{i}|^{3}}}}" loading="lazy"></span></dd></dl>
<p>wobei <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {r}}_{i}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
</mrow>
</msub>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {r}}_{i}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/de93eb4c8bca39012a94e9809c45d7fd677bf975.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.023ex; height:2.676ex;" alt="{\displaystyle {\vec {r}}_{i}}" loading="lazy"></span> die Orte der Punktmassen <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle m_{i}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>m</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
</mrow>
</msub>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle m_{i}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/95ec8e804f69706d3f5ad235f4f983220c8df7c2.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.84ex; height:2.009ex;" alt="{\displaystyle m_{i}}" loading="lazy"></span> sind. Für kontinuierliche Masseverteilungen gilt:
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\vec {g}}({\vec {r}})=-G\int \rho ({\vec {r}}'){\frac {{\vec {r}}-{\vec {r}}'}{|{\vec {r}}-{\vec {r}}'|^{3}}}\,\mathrm {d} ^{3}{\vec {r}}'}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>g</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mi>G</mi>
<mo>∫<!-- ∫ --></mo>
<mi>ρ<!-- ρ --></mi>
<mo stretchy="false">(</mo>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>′</mo>
</msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>−<!-- − --></mo>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>′</mo>
</msup>
</mrow>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>−<!-- − --></mo>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>′</mo>
</msup>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
<mspace width="thinmathspace"></mspace>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo>′</mo>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\vec {g}}({\vec {r}})=-G\int \rho ({\vec {r}}'){\frac {{\vec {r}}-{\vec {r}}'}{|{\vec {r}}-{\vec {r}}'|^{3}}}\,\mathrm {d} ^{3}{\vec {r}}'}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/a5e9f5b51e79cce538ecf6fd00fb41592278ed1c.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.005ex; width:32.624ex; height:6.843ex;" alt="{\displaystyle {\vec {g}}({\vec {r}})=-G\int \rho ({\vec {r}}'){\frac {{\vec {r}}-{\vec {r}}'}{|{\vec {r}}-{\vec {r}}'|^{3}}}\,\mathrm {d} ^{3}{\vec {r}}'}" loading="lazy"></span></dd></dl>
<p>wobei <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \rho ({\vec {r}})}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>ρ<!-- ρ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mi>r</mi>
<mo stretchy="false">→<!-- → --></mo>
</mover>
</mrow>
</mrow>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \rho ({\vec {r}})}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/c80c262b5476b043478d88adb73498aac8b80de9.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:4.234ex; height:2.843ex;" alt="{\displaystyle \rho ({\vec {r}})}" loading="lazy"></span> die Massendichteverteilung ist.
</p>
<div class="mw-heading mw-heading2"><h2 id="Gravitative_Bindungsenergie">Gravitative Bindungsenergie</h2></div>
<p>Um einen durch Gravitation zusammengehaltenen Körper (z. B. die Erde) in seine Bestandteile zu zerlegen und diese trotz der Gravitationskraft zwischen ihnen unendlich weit voneinander zu entfernen, ist eine bestimmte Energiemenge nötig. Umgekehrt wird die gleiche Energiemenge freigesetzt, wenn sich diese Bestandteile (beispielsweise beim Kollaps einer Gaswolke) zu einem kompakteren Himmelskörper, etwa einem Stern oder einem Planeten zusammenfügen.
</p>
<div class="mw-heading mw-heading3"><h3 id="Klassische_Rechnung_für_eine_homogene_Kugel"><span id="Klassische_Rechnung_f.C3.BCr_eine_homogene_Kugel"></span>Klassische Rechnung für eine homogene Kugel</h3></div>
<p>Die <a href="Bindungsenergie" title="Bindungsenergie">Bindungsenergie</a> <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>E</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle E}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/4232c9de2ee3eec0a9c0a19b15ab92daa6223f9b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.776ex; height:2.176ex;" alt="{\displaystyle E}" loading="lazy"></span> einer homogenen Kugel ergibt sich aus der Überlegung, die Kugel schichtweise aufzubauen, indem aus dem Unendlichen kommende Materie angefügt wird. Hat die Kugel einen Radius <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>r</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle r}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0d1ecb613aa2984f0576f70f86650b7c2a132538.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.049ex; height:1.676ex;" alt="{\displaystyle r}" loading="lazy"></span> erreicht, ist ihr Volumen <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V(r)={\frac {4\pi }{3}}r^{3}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>V</mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>4</mn>
<mi>π<!-- π --></mi>
</mrow>
<mn>3</mn>
</mfrac>
</mrow>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle V(r)={\frac {4\pi }{3}}r^{3}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/ba23f7ef246308e6260dd1b79bf0bec1a3e72d12.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:13.177ex; height:5.176ex;" alt="{\displaystyle V(r)={\frac {4\pi }{3}}r^{3}}" loading="lazy"></span> und bei konstanter Dichte <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \rho }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>ρ<!-- ρ --></mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \rho }</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/1f7d439671d1289b6a816e6af7a304be40608d64.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:1.202ex; height:2.176ex;" alt="{\displaystyle \rho }" loading="lazy"></span> ihre Masse
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M(r)=\rho V(r)={\frac {4\pi }{3}}\rho \ r^{3}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>M</mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mi>ρ<!-- ρ --></mi>
<mi>V</mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>4</mn>
<mi>π<!-- π --></mi>
</mrow>
<mn>3</mn>
</mfrac>
</mrow>
<mi>ρ<!-- ρ --></mi>
<mtext> </mtext>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle M(r)=\rho V(r)={\frac {4\pi }{3}}\rho \ r^{3}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/402a19c7dd1f7c6eaafad2137f31c51cd3eaa709.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:24.56ex; height:5.176ex;" alt="{\displaystyle M(r)=\rho V(r)={\frac {4\pi }{3}}\rho \ r^{3}}" loading="lazy"></span>.</dd></dl>
<p>Sie erzeugt im Außenraum (<span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r'>r}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>r</mi>
<mo>′</mo>
</msup>
<mo>></mo>
<mi>r</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle r'>r}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f92c6322c800d3c9d5bd536698848ee3f124a3ad.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:5.88ex; height:2.509ex;" alt="{\displaystyle r'>r}" loading="lazy"></span>) das <a href="Gravitationspotential" class="mw-redirect" title="Gravitationspotential">Gravitationspotential</a>
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Phi _{r}(r')=-{\frac {G\,M(r)}{r'}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>r</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<msup>
<mi>r</mi>
<mo>′</mo>
</msup>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>G</mi>
<mspace width="thinmathspace"></mspace>
<mi>M</mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
</mrow>
<msup>
<mi>r</mi>
<mo>′</mo>
</msup>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \Phi _{r}(r')=-{\frac {G\,M(r)}{r'}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/802dbf86c3d538ef381b440f92377e832f6f711a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:19.451ex; height:5.676ex;" alt="{\displaystyle \Phi _{r}(r')=-{\frac {G\,M(r)}{r'}}}" loading="lazy"></span>.</dd></dl>
<p>Die nächste Schicht der Dicke <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {d} r}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathrm {d} r}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/6061c91ecd3f8919bce745870bb757249fe26bc3.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.341ex; height:2.176ex;" alt="{\displaystyle \mathrm {d} r}" loading="lazy"></span> bedeckt die Oberfläche <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A(r)=4\pi r^{2}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>A</mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mn>4</mn>
<mi>π<!-- π --></mi>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle A(r)=4\pi r^{2}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/4c8ecdb15909d7069ea4209aa3a07274b1965bb3.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:12.297ex; height:3.176ex;" alt="{\displaystyle A(r)=4\pi r^{2}}" loading="lazy"></span> und hat (bei gleicher Dichte) die Masse
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {d} m=\rho A(r)\,\mathrm {d} r=4\pi \rho \ r^{2}\ \mathrm {d} r\,}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>m</mi>
<mo>=</mo>
<mi>ρ<!-- ρ --></mi>
<mi>A</mi>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
<mo>=</mo>
<mn>4</mn>
<mi>π<!-- π --></mi>
<mi>ρ<!-- ρ --></mi>
<mtext> </mtext>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mtext> </mtext>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
<mspace width="thinmathspace"></mspace>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathrm {d} m=\rho A(r)\,\mathrm {d} r=4\pi \rho \ r^{2}\ \mathrm {d} r\,}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/4237c6df39c9a63d17b4ee62efe0ff877e6b72b6.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:27.75ex; height:3.176ex;" alt="{\displaystyle \mathrm {d} m=\rho A(r)\,\mathrm {d} r=4\pi \rho \ r^{2}\ \mathrm {d} r\,}" loading="lazy"></span>.</dd></dl>
<p>Die dabei freiwerdende Energie ist
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {d} E=-\Phi _{r}(r)\,\mathrm {d} m={\frac {G}{r}}\cdot {\frac {4\pi }{3}}\rho \,r^{3}\cdot 4\pi \rho r^{2}\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}r^{4}\,\mathrm {d} r}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>E</mi>
<mo>=</mo>
<mo>−<!-- − --></mo>
<msub>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>r</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>r</mi>
<mo stretchy="false">)</mo>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>m</mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>G</mi>
<mi>r</mi>
</mfrac>
</mrow>
<mo>⋅<!-- ⋅ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>4</mn>
<mi>π<!-- π --></mi>
</mrow>
<mn>3</mn>
</mfrac>
</mrow>
<mi>ρ<!-- ρ --></mi>
<mspace width="thinmathspace"></mspace>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<mo>⋅<!-- ⋅ --></mo>
<mn>4</mn>
<mi>π<!-- π --></mi>
<mi>ρ<!-- ρ --></mi>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>16</mn>
<msup>
<mi>π<!-- π --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mn>3</mn>
</mfrac>
</mrow>
<mi>G</mi>
<msup>
<mi>ρ<!-- ρ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>4</mn>
</mrow>
</msup>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathrm {d} E=-\Phi _{r}(r)\,\mathrm {d} m={\frac {G}{r}}\cdot {\frac {4\pi }{3}}\rho \,r^{3}\cdot 4\pi \rho r^{2}\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}r^{4}\,\mathrm {d} r}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/a2834171087621397906a11ea5b04c3c8dbfff3b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:59.049ex; height:5.676ex;" alt="{\displaystyle \mathrm {d} E=-\Phi _{r}(r)\,\mathrm {d} m={\frac {G}{r}}\cdot {\frac {4\pi }{3}}\rho \,r^{3}\cdot 4\pi \rho r^{2}\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}r^{4}\,\mathrm {d} r}" loading="lazy"></span> .</dd></dl>
<p>Baut man so Schicht für Schicht eine Kugel mit Radius <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle R}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>R</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle R}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/4b0bfb3769bf24d80e15374dc37b0441e2616e33.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.764ex; height:2.176ex;" alt="{\displaystyle R}" loading="lazy"></span> und Masse <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M=M(R)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>M</mi>
<mo>=</mo>
<mi>M</mi>
<mo stretchy="false">(</mo>
<mi>R</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle M=M(R)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/45546036a5120f7111d6b9d54fc333dd4fc4ece9.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:11.556ex; height:2.843ex;" alt="{\displaystyle M=M(R)}" loading="lazy"></span> zusammen, so wird insgesamt die folgende Bindungsenergie frei:
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E=\int _{0}^{R}{\frac {\mathrm {d} E}{\mathrm {d} r}}\,\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}\int _{0}^{R}r^{4}\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}{\frac {1}{5}}R^{5}={\frac {3}{5}}{\frac {G}{R}}\ \left({\frac {4\pi R^{3}}{3}}\ \rho \right)^{2}={\frac {3}{5}}{\frac {GM^{2}}{R}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>E</mi>
<mo>=</mo>
<msubsup>
<mo>∫<!-- ∫ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>0</mn>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>R</mi>
</mrow>
</msubsup>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>E</mi>
</mrow>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
</mrow>
</mfrac>
</mrow>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>16</mn>
<msup>
<mi>π<!-- π --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mn>3</mn>
</mfrac>
</mrow>
<mi>G</mi>
<msup>
<mi>ρ<!-- ρ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<msubsup>
<mo>∫<!-- ∫ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>0</mn>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>R</mi>
</mrow>
</msubsup>
<msup>
<mi>r</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>4</mn>
</mrow>
</msup>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">d</mi>
</mrow>
<mi>r</mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>16</mn>
<msup>
<mi>π<!-- π --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mn>3</mn>
</mfrac>
</mrow>
<mi>G</mi>
<msup>
<mi>ρ<!-- ρ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>5</mn>
</mfrac>
</mrow>
<msup>
<mi>R</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>5</mn>
</mrow>
</msup>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>3</mn>
<mn>5</mn>
</mfrac>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>G</mi>
<mi>R</mi>
</mfrac>
</mrow>
<mtext> </mtext>
<msup>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>4</mn>
<mi>π<!-- π --></mi>
<msup>
<mi>R</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
</mrow>
<mn>3</mn>
</mfrac>
</mrow>
<mtext> </mtext>
<mi>ρ<!-- ρ --></mi>
</mrow>
<mo>)</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>3</mn>
<mn>5</mn>
</mfrac>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>G</mi>
<msup>
<mi>M</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mi>R</mi>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle E=\int _{0}^{R}{\frac {\mathrm {d} E}{\mathrm {d} r}}\,\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}\int _{0}^{R}r^{4}\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}{\frac {1}{5}}R^{5}={\frac {3}{5}}{\frac {G}{R}}\ \left({\frac {4\pi R^{3}}{3}}\ \rho \right)^{2}={\frac {3}{5}}{\frac {GM^{2}}{R}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/a5c79743f78719f6cd59ea304cd657e4687bc7ff.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:87.338ex; height:6.676ex;" alt="{\displaystyle E=\int _{0}^{R}{\frac {\mathrm {d} E}{\mathrm {d} r}}\,\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}\int _{0}^{R}r^{4}\mathrm {d} r={\frac {16\pi ^{2}}{3}}G\rho ^{2}{\frac {1}{5}}R^{5}={\frac {3}{5}}{\frac {G}{R}}\ \left({\frac {4\pi R^{3}}{3}}\ \rho \right)^{2}={\frac {3}{5}}{\frac {GM^{2}}{R}}}" loading="lazy"></span></dd></dl>
<p>Die Bindungsenergie beträgt also
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E={\frac {3\,G\,M^{2}}{5\,R}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>E</mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>3</mn>
<mspace width="thinmathspace"></mspace>
<mi>G</mi>
<mspace width="thinmathspace"></mspace>
<msup>
<mi>M</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mrow>
<mn>5</mn>
<mspace width="thinmathspace"></mspace>
<mi>R</mi>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle E={\frac {3\,G\,M^{2}}{5\,R}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/900275f76358945138a254a5350df59576b19aa9.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:13.027ex; height:5.843ex;" alt="{\displaystyle E={\frac {3\,G\,M^{2}}{5\,R}}}" loading="lazy"></span> .</dd></dl>
<p>Eine homogene Kugel mit Masse und Radius der Erde besäße nach dieser Formel eine gravitative Bindungsenergie von etwa 2,24 · 10<sup>32</sup> <a href="Joule" title="Joule">J</a>. Die Erde ist allerdings keine Kugel homogener Dichte, der <a href="Innerer_Aufbau_der_Erde" title="Innerer Aufbau der Erde">Erdkern</a> hat eine fast doppelt so hohe Dichte wie der Erdmantel. Aus der Dichteverteilung im Erdinnern nach dem „<a href="PREM" title="PREM">Preliminary Reference Earth Model</a>“ (PREM) errechnet sich die Bindungsenergie der Erde daher etwas größer, nämlich zu 2,489 · 10<sup>32</sup> <a href="Joule" title="Joule">J</a>.
</p>
<div class="mw-heading mw-heading3"><h3 id="Allgemeine_Relativitätstheorie"><span id="Allgemeine_Relativit.C3.A4tstheorie"></span>Allgemeine Relativitätstheorie</h3></div>
<p>Nach der Allgemeinen Relativitätstheorie berechnet sich die Bindungsenergie im Gravitationspotential mit dem Shapirofaktor <i>σ</i> aus der Ruheenergie <i>m</i> im Nullpotential
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \sigma ={\sqrt {1-rs/r}}={\sqrt {1-{\frac {2MG}{c^{2}r}}}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>σ<!-- σ --></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>r</mi>
<mi>s</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mi>r</mi>
</msqrt>
</mrow>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>2</mn>
<mi>M</mi>
<mi>G</mi>
</mrow>
<mrow>
<msup>
<mi>c</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mi>r</mi>
</mrow>
</mfrac>
</mrow>
</msqrt>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \sigma ={\sqrt {1-rs/r}}={\sqrt {1-{\frac {2MG}{c^{2}r}}}}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/b0beb0c6d7ddc048292f04c17f0f20031c0ad5d6.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; width:30.798ex; height:6.343ex;" alt="{\displaystyle \sigma ={\sqrt {1-rs/r}}={\sqrt {1-{\frac {2MG}{c^{2}r}}}}}" loading="lazy"></span></dd>
<dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{\text{B}}=c^{2}m-c^{2}M=(1-\sigma )c^{2}m}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>E</mi>
<mrow class="MJX-TeXAtom-ORD">
<mtext>B</mtext>
</mrow>
</msub>
<mo>=</mo>
<msup>
<mi>c</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mi>m</mi>
<mo>−<!-- − --></mo>
<msup>
<mi>c</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mi>M</mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>σ<!-- σ --></mi>
<mo stretchy="false">)</mo>
<msup>
<mi>c</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mi>m</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle E_{\text{B}}=c^{2}m-c^{2}M=(1-\sigma )c^{2}m}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/ab3b316213db042c5633d406ec4409b4b224d9e2.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:31.996ex; height:3.176ex;" alt="{\displaystyle E_{\text{B}}=c^{2}m-c^{2}M=(1-\sigma )c^{2}m}" loading="lazy"></span></dd></dl>
<p>Für eine Hohlkugel mit Radius <i>r</i> ergibt sich dann die Eigenbindungsenergie aus der gemessenen Masse <i>M</i>
</p>
<dl><dd><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{\text{B}}=c^{2}m-c^{2}M=c^{2}M\left({\frac {1}{\sqrt {1-{\tfrac {2GM}{c^{2}r}}}}}-1\right)}">
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<annotation encoding="application/x-tex">{\displaystyle E_{\text{B}}=c^{2}m-c^{2}M=c^{2}M\left({\frac {1}{\sqrt {1-{\tfrac {2GM}{c^{2}r}}}}}-1\right)}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/38aeef3b00430e9bda6486da863d2750bb1daf47.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -4.671ex; width:45.553ex; height:10.509ex;" alt="{\displaystyle E_{\text{B}}=c^{2}m-c^{2}M=c^{2}M\left({\frac {1}{\sqrt {1-{\tfrac {2GM}{c^{2}r}}}}}-1\right)}" loading="lazy"></span></dd></dl>
<div class="mw-heading mw-heading2"><h2 id="Literatur">Literatur</h2></div>
<ul><li><a href="Wolfgang_Demtr%C3%B6der" title="Wolfgang Demtröder">Wolfgang Demtröder</a>: <cite style="font-style:italic">Experimentalphysik 1</cite>. Springer, 2006, ISBN 978-3-540-26034-9.<span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rfr_id=info:sid/de.wikipedia.org:Gravitationsfeld&rft.au=Wolfgang+Demtr%C3%B6der&rft.btitle=Experimentalphysik+1&rft.date=2006&rft.genre=book&rft.isbn=9783540260349&rft.pub=Springer" style="display:none"> </span></li>
<li><a href="Horst_St%C3%B6cker" title="Horst Stöcker">Horst Stöcker</a>: <cite style="font-style:italic">Taschenbuch der Physik</cite>. 6. Auflage. Harri Deutsch, Leck 2010, ISBN 978-3-8171-1860-1, <span style="white-space:nowrap">S.<span style="display:inline-block;width:.2em"> </span>124</span>.<span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rfr_id=info:sid/de.wikipedia.org:Gravitationsfeld&rft.au=Horst+St%C3%B6cker&rft.btitle=Taschenbuch+der+Physik&rft.date=2010&rft.edition=6&rft.genre=book&rft.isbn=9783817118601&rft.pages=124&rft.place=Leck&rft.pub=Harri+Deutsch" style="display:none"> </span></li></ul>
<div class="mw-heading mw-heading2"><h2 id="Weblinks">Weblinks</h2></div>
<ul><li><a rel="nofollow" class="external text" href="https://portal.dnb.de/opac.htm?method=simpleSearch&query=4072014-7">Literatur von und über Gravitationsfeld</a> im Katalog der <a href="Deutsche_Nationalbibliothek" title="Deutsche Nationalbibliothek">Deutschen Nationalbibliothek</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="Einzelnachweise">Einzelnachweise</h2></div>
<ol class="references">
<li id="cite_note-1"><span class="mw-cite-backlink"><a href="#cite_ref-1">↑</a></span> <span class="reference-text"><span class="cite">Olaf Fischer: <a rel="nofollow" class="external text" href="https://www.spektrum.de/sixcms/media.php/1308/modell.pdf"><i>Planeten- und Kometenbewegung im Modell vom Potentialtrichter.</i></a> In: <i>Wissenschaft in die Schulen!</i> Spektrum, 31. Juli 2019,<span class="Abrufdatum"> abgerufen am 29. Oktober 2019</span>.</span><span style="display: none;" class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2Fde.wikipedia.org%3AGravitationsfeld&rft.title=Planeten-+und+Kometenbewegung+im+Modell+vom+Potentialtrichter&rft.description=Planeten-+und+Kometenbewegung+im+Modell+vom+Potentialtrichter&rft.identifier=https%3A%2F%2Fwww.spektrum.de%2Fsixcms%2Fmedia.php%2F1308%2Fmodell.pdf&rft.creator=Olaf+Fischer&rft.publisher=Spektrum&rft.date=2019-07-31"> </span></span>
</li>
</ol>
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Normdaten (Sachbegriff): <a href="Gemeinsame_Normdatei" title="Gemeinsame Normdatei">GND</a>: <span class="-print"><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4072014-7">4072014-7</a></span> | <a href="Library_of_Congress_Control_Number" title="Library of Congress Control Number">LCCN</a>: <span class="-print"><a rel="nofollow" class="external text" href="https://id.loc.gov/authorities/sh85056560">sh85056560</a></span> </div>
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