<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>neom</author><text>These PBS Spacetime episodes should help:&lt;p&gt;The Speed of Light is NOT About Light - &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=msVuCEs8Ydo&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=msVuCEs8Ydo&lt;/a&gt;&lt;p&gt;Is Quantum Tunneling Faster than Light? - &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=-IfmgyXs7z8&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=-IfmgyXs7z8&lt;/a&gt;&lt;p&gt;The Quantum Experiment that Broke Reality - &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=RlXdsyctD50&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=RlXdsyctD50&lt;/a&gt;&lt;p&gt;Pilot Wave Theory and Quantum Realism -  &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=RlXdsyctD50&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=RlXdsyctD50&lt;/a&gt;&lt;p&gt;The Future of Gravitational Waves - &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=eJ2RNBAFLj0&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.youtube.com&amp;#x2F;watch?v=eJ2RNBAFLj0&lt;/a&gt;</text><parent_chain><item><author>saganus</author><text>This might be a naive question, but I&amp;#x27;d like to clear it out.&lt;p&gt;Do gravitational waves travel at the speed of light?&lt;p&gt;I know the theory says nothing can travel faster than light. I also know that photons can be seen as quanta or as waves. So my guess is that gravitational waves travel at most, at the speed of light.&lt;p&gt;But do they? or do they travel slower? faster? Is there a doppler effect for GWs?&lt;p&gt;I ask because I would think ripples in the space-time fabric itself might be a bit different than light waves or other more studied phenomena.&lt;p&gt;Can anyone point me in the right direction?</text></item></parent_chain></comment><story><title>Rumours swell over new kind of gravitational-wave sighting</title><url>http://www.nature.com/news/rumours-swell-over-new-kind-of-gravitational-wave-sighting-1.22482</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>bramen</author><text>The speed of light is sometimes referred to as the speed of causality, and it seems like it&amp;#x27;s more of a fundamental speed limit on the propagation of events or information through space.</text><parent_chain><item><author>saganus</author><text>This might be a naive question, but I&amp;#x27;d like to clear it out.&lt;p&gt;Do gravitational waves travel at the speed of light?&lt;p&gt;I know the theory says nothing can travel faster than light. I also know that photons can be seen as quanta or as waves. So my guess is that gravitational waves travel at most, at the speed of light.&lt;p&gt;But do they? or do they travel slower? faster? Is there a doppler effect for GWs?&lt;p&gt;I ask because I would think ripples in the space-time fabric itself might be a bit different than light waves or other more studied phenomena.&lt;p&gt;Can anyone point me in the right direction?</text></item></parent_chain></comment><story><title>Rumours swell over new kind of gravitational-wave sighting</title><url>http://www.nature.com/news/rumours-swell-over-new-kind-of-gravitational-wave-sighting-1.22482</url></story>