<story><title>Mysterious deep-space flashes repeat every 157 days</title><url>https://www.space.com/mysterious-fast-radio-burst-repeater.html</url></story><parent_chain><item><author>Vysero</author><text>The idea that aliens would use these to propel ships is rather ludicrous, and highly unlikely. The nearest galaxy is 25k light years away so even at the maximum speed it would take 25 thousand years to travel here.&lt;p&gt;That being said, it must be something exceptionally energetic.. wish I could see it.</text></item></parent_chain><comment><author>marcinzm</author><text>Why do you assume they need to travel between galaxies? They could be going to the next solar system over and we&amp;#x27;re simply seeing the leakage of their propulsion. Just because the light travels across galaxies doesn&amp;#x27;t mean it&amp;#x27;s purpose is to travel across galaxies. Moreover, a species that can unleash this much energy has probably conquered such things as mortality and age related decay.</text></comment>
<story><title>Mysterious deep-space flashes repeat every 157 days</title><url>https://www.space.com/mysterious-fast-radio-burst-repeater.html</url></story><parent_chain><item><author>Vysero</author><text>The idea that aliens would use these to propel ships is rather ludicrous, and highly unlikely. The nearest galaxy is 25k light years away so even at the maximum speed it would take 25 thousand years to travel here.&lt;p&gt;That being said, it must be something exceptionally energetic.. wish I could see it.</text></item></parent_chain><comment><author>TomBombadildoze</author><text>&amp;gt; The nearest galaxy is 25k light years away so even at the maximum speed it would take 25 thousand years to travel here.&lt;p&gt;Given your arithmetic, I assume by &amp;quot;maximum speed&amp;quot; you mean the speed of light, in which case travel wouldn&amp;#x27;t take 25k years. It would in fact be &lt;i&gt;instantaneous&lt;/i&gt;. At relativistic speeds, distances contract and time dilates.&lt;p&gt;Now, this is all moot because this:&lt;p&gt;&amp;gt; The idea that aliens would use these to propel ships is rather ludicrous, and highly unlikely.&lt;p&gt;... is absolutely correct. No amount of energy will propel a massive object to the speed of light.&lt;p&gt;edit: I realized I may have misinterpreted. From the perspective of someone watching their own kind travel that expanse, it would indeed appear &lt;i&gt;to the outside observer&lt;/i&gt; to take 25k years to travel.</text></comment>