this post was submitted on 01 May 2025
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[–] bufalo1973@lemm.ee 6 points 19 hours ago (1 children)

I think that doesn't account on the effect of gravity on the cardboard. That mass would crush the center of the sphere, making it smaller. So more material would be needed, and more pressure to the core.

[–] Ludrol@szmer.info 13 points 19 hours ago (1 children)

I don't get your concern.

Cardboard cutout is flat. We set the cutout to be the size of the sun. When the time starts affecting it, yes the gravity tries to collapse it onto the sphere but mass stays the same and gravity exerted "outside" is the same.

[–] bufalo1973@lemm.ee 2 points 15 hours ago (1 children)

Even if it's flat, gravity works in that direction (radial).

[–] Ludrol@szmer.info 0 points 13 hours ago (1 children)
[–] bufalo1973@lemm.ee 1 points 7 hours ago (1 children)

Put a sheet of paper vertical and let gravity do its work. What happens? Then think about a BIG "sheet" that has gravity by itself. You end up with a ball.

[–] Ludrol@szmer.info 1 points 7 hours ago

yes:

  1. that ball has 10^18^ kg mass
  2. that ball falls on earth and burns all the oxygen (debatable) or the cutout falls on earth like a big wrapper and burns evenly.