<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>tzs</author><text>The History Channel had a 20 episode series called &lt;i&gt;Life After People&lt;/i&gt; that looked at what would happen if every human suddenly disappeared.&lt;p&gt;The National Geographic had a similar, but only one episode program looking at that questions, called &lt;i&gt;Aftermath: Population Zero&lt;/i&gt;.&lt;p&gt;I have a vague recollection of seeing something like this on one of Discovery&amp;#x27;s channels, too, but I may be mixing that up with an article in their magazine.&lt;p&gt;My recollection is that they all concluded that in the very long term (tens of millions of years), if some other species evolved intelligence it would probably not be able to tell we were here.&lt;p&gt;Some of the materials we used might survive, but things like glaciers in ice ages would grind them to a powder. The next intelligent species might notice these odd concentrations of unusual combinations of metal particles and powdered long chain carbon compounds, but there would be nothing to tell them it wasn&amp;#x27;t made by some unknown natural process.</text><parent_chain></parent_chain></comment><story><title>If we weren’t the first industrial civilization on Earth, would we ever know?</title><url>https://www.technologyreview.com/s/610886/if-we-werent-the-first-industrial-civilization-on-earth-would-we-ever-know/</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>klodolph</author><text>We are the first nuclear civilization.&lt;p&gt;We know the expected isotope ratios too well and test them too often. This is how we discovered evidence of a natural nuclear reactor from 1.7 Gya. Any other nuclear civilization would have changed the isotope ratios in detectable ways in some part of the world.</text><parent_chain></parent_chain></comment><story><title>If we weren’t the first industrial civilization on Earth, would we ever know?</title><url>https://www.technologyreview.com/s/610886/if-we-werent-the-first-industrial-civilization-on-earth-would-we-ever-know/</url></story>