<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>jillesvangurp</author><text>Wild  idea: build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. That would likely be something that fitness people and professional athletes would be interested in. And it&amp;#x27;s a good dry run for building and operating these things on Mars and the Moon. If we can make these things work on Earth, making them work in lower gravity is only going to be easier as the g-forces would be lower.&lt;p&gt;A train or roller coaster on a slightly tilted circular track would probably do the job. A slight tilt would just move the gravity vector orthogonal to the floor.</text><parent_chain><item><author>Nevermark</author><text>I didn&amp;#x27;t see any mention of having a spinning surface.&lt;p&gt;A tapered cylinder &amp;quot;gravity gym&amp;quot; with adjustable angled walls, and variable speed spinning, could smoothly create much greater &amp;quot;gravity&amp;quot;.&lt;p&gt;Spin gravity would also enable body weight exercises, core exercises, stationary or small area cardio like exercise bikes, VR games, yoga, etc. Even sleeping.&lt;p&gt;&lt;i&gt;EDIT: I missed this:&lt;/i&gt;&lt;p&gt;&amp;gt; but Moon-based centrifuges allowing locomotion inside would pose technical challenges&lt;p&gt;Still think it will be inevitable. Far more useful physically and psychologically. &amp;quot;Spinning surface&amp;quot; is a simple challenge, compared to &amp;quot;low-g health deterioration&amp;quot; and &amp;quot;bored to death of running in circles&amp;quot;.&lt;p&gt;Equipment like this might resolve issues with off-world childbearing. Time to &amp;quot;spin up&amp;quot; some space rabbits and see what we get! (Hopefully not tribbles.)&lt;p&gt;Spin areas will surely become ubiquitous in all low gravity colonies.&lt;p&gt;Startup anyone?</text></item></parent_chain></comment><story><title>Horizontal running inside circular walls of Moon settlements</title><url>https://royalsocietypublishing.org/doi/10.1098/rsos.231906</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>fallingsquirrel</author><text>You probably know this already, but for a while people were toying with the idea of a &amp;quot;childbirth centrifuge&amp;quot;. &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;patents.google.com&amp;#x2F;patent&amp;#x2F;US3216423A&amp;#x2F;en&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;patents.google.com&amp;#x2F;patent&amp;#x2F;US3216423A&amp;#x2F;en&lt;/a&gt;&lt;p&gt;There&amp;#x27;s probably a reason it never caught on.</text><parent_chain><item><author>Nevermark</author><text>I didn&amp;#x27;t see any mention of having a spinning surface.&lt;p&gt;A tapered cylinder &amp;quot;gravity gym&amp;quot; with adjustable angled walls, and variable speed spinning, could smoothly create much greater &amp;quot;gravity&amp;quot;.&lt;p&gt;Spin gravity would also enable body weight exercises, core exercises, stationary or small area cardio like exercise bikes, VR games, yoga, etc. Even sleeping.&lt;p&gt;&lt;i&gt;EDIT: I missed this:&lt;/i&gt;&lt;p&gt;&amp;gt; but Moon-based centrifuges allowing locomotion inside would pose technical challenges&lt;p&gt;Still think it will be inevitable. Far more useful physically and psychologically. &amp;quot;Spinning surface&amp;quot; is a simple challenge, compared to &amp;quot;low-g health deterioration&amp;quot; and &amp;quot;bored to death of running in circles&amp;quot;.&lt;p&gt;Equipment like this might resolve issues with off-world childbearing. Time to &amp;quot;spin up&amp;quot; some space rabbits and see what we get! (Hopefully not tribbles.)&lt;p&gt;Spin areas will surely become ubiquitous in all low gravity colonies.&lt;p&gt;Startup anyone?</text></item></parent_chain></comment><story><title>Horizontal running inside circular walls of Moon settlements</title><url>https://royalsocietypublishing.org/doi/10.1098/rsos.231906</url></story>