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.
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.
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.
Even if it’s flat, gravity works in that direction (radial).
Yes, and?
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.
yes: