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Suppose there is a Dyson sphere earth thick, on the inner surface would the gravity be pointing outwards of centre of sphere with same strength as Earth's gravity?

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  • $\begingroup$ The only gravity on the inside would be coming from the material that's inside the sphere, i.e. from the star that's supposedly on the inside. Let's just say that you wouldn't want to fall out of one of the inner windows, it wouldn't end well after approx. half a year of fall time for an Earth orbit size Dyson sphere surrounding a one solar mass star. Having said that, such a sphere can not be built, so it's not an actual problem that anybody could ever have. $\endgroup$ – CuriousOne Aug 5 '16 at 10:02
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    $\begingroup$ In fictional accounts, the Dyson-sphere concept is often interpreted as an artificial hollow sphere of matter around a star. This perception is based on a literal interpretation of Dyson's original short paper introducing the concept. In response to letters prompted by this paper, Dyson replied, "A solid shell or ring surrounding a star is mechanically impossible. The form of 'biosphere' which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star." From : en.wikipedia.org/wiki/Dyson_sphere $\endgroup$ – user108787 Aug 5 '16 at 10:05
  • $\begingroup$ @CuriousOne I vividly remember Ringworld, I wonder could that be built. As a kid I had over 400 SF books, 90% of them (wherever they are now), I could not read today,the ideas were great, plots and prose...... not so much. $\endgroup$ – user108787 Aug 5 '16 at 10:14
  • $\begingroup$ @count_to_10: Sounds like a really bad idea to have disks that are on average like 10m thick and maybe 10-100km in diameter flying around at up to 30+ km/s of differential velocity, or so. :-) The best scifi books are the ones that have next to no science and 100% fiction in them. I pretty much gave up on anything but Lem and the Strugatzki brothers in the end. There may be a few more quality authors that I don't know, but nothing I have ever read comes even close to these three authors. $\endgroup$ – CuriousOne Aug 5 '16 at 10:14
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    $\begingroup$ Duplicate of physics.stackexchange.com/q/268109 $\endgroup$ – user108787 Aug 5 '16 at 10:19