>: <span class="tsd-signature-type">number</span></h5></li></ul></div><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">number</span></h4><p>the default implementation returns zero.</p>
</li></ul></section><section class="tsd-panel tsd-member"><a id="gravitationalMass" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><code class="tsd-tag ts-flagVirtual">Virtual</code><span>gravitational<wbr/>Mass</span><a href="#gravitationalMass" aria-label="Permalink" class="tsd-anchor-icon"><svg vi