Thoughts about sphere worlds

[Omnicron1]

infallibility is a bore and everyday is a learning experience but i still don't think centrifugal force could hold down an atmosphere as for all other statements granted i was wrong... but no one touched the statement about the economic ramifications of such a project...

if you could overcome all the inherent engineering problems with building a sphere world why when your moving this many solar systems worth of matter around this sun don't you sift out the important parts? I think the only thing you should be able to extract from ringworlds and sphereworlds are organics, population and energy which is everything but minerals i guess what im saying here is why on earth are you mining resources from something you built?! I think looking at the real cost of one of these things it'd be more efficient to build a huge close-formation satellite field around the star to gather its energy...If it ever gets built it will be more a monument of achievement (tower of Pisa or Lady Liberty) than a useful source of resources though it'd be great place to stick all those naggy scientist characters!!

military strategms of a sphere world... If you can somehow manage the intense heat of the star that a sphereworld would generate>>then when someone attacks you why dont you just aim that crap in their general direction....... more food for thought

also i want to give a hand to all the great minds assembled here i've taken 5 AP courses including AP Calculus and AP Chemistry and i could neer have carried on such engaging and fascinating conversations and everyone has good points...even when they prove me wrong!!

[PvK]

Originally posted by Loser:
The gravity of a shell is not precieved by objects within the shell. For this reason, the gravity you experience will grow less and less as you penetrate deeper and deeper into a body such as the Earth.

Gravity applies inside a shell, but if you're inside, the shell's gravitation comes from all sides, so some of it cancels out some of the rest. It then depends on where you are within the shell, and whether the shell is of uniform density or not. A Dyson sphere's own gravity would be a major factor in its engineering.

...From the outside, the shell will will be an immense amount of gravity. But if the outside surface is spinning, and it will be spinning much faster than the earth's orbital velocity, then at the equator one would be thrown off at around 1 G.

Naturally. If you design the spin so interior objects have a 1G acceleration towards the inside, then objects on the outside will fly off at 1G. On a ringworld, or the equator of a sphereworld with no scifi artificial gravity on the equator.

In thruth it would be pretty damn hard to ladn on, you'd have to be on one wicked eliptic... though I could have the scale wrong.

Certainly it'd a much simpler problem than assembling the contraption in the first place.

Try flying through a docking port and landing on the inside.

Additionally, no human would be able to run or jump fast enough agaisnt the spin of the world to escape it and start floating. I believe, in order to get the 1 G, you'd have to be cranking damn fast.

Try jumping off the Earth (no offense; I only suggest it because I'm sure you won't succeed) - it's exactly the same amount of difficulty - that's the point.

PvK

[PvK]

Originally posted by Omnicron1:
...
about centriFugal force (someone said Centripetal and thats the opposite) not being a good artificial gravity...

See for example THIS page about "Centrifugal" vs. "Centripetal", which says, in part:

For those who don't know, when you are in a rotating space colony, your feet exert a centrifugal force on the floor, whereas the floor exerts a centripetal force on your feet. Hence, artificial gravity as regards a force on your body is a centripetal force. They're equal and opposite forces of the same phenomenon. Your feet exert the centrifugal force onto the floor of a rotating space colony.

PvK

[PvK]

As for economic aspects, yes Omicron, I imagine, as I more or less said before, that if you can move the matter from many solar systems to one in order to build a Dyson sphere, and build it and get it to work, then I tend to think there would be many other more practical and/or interesting things you could have done with your time and energy. As you say, resource extraction is a much smaller task than the above.

PvK

[Taera]

You guys are nuts.

[narf poit chez BOOM]

i don't remember who wrote it.

[Parasite]

Originally posted by gregebowman:
but there's a series by David Brin that involves intelligent dolphins using space suits. I just can't remember the name of the series, however.

Check out "Startide Rising" about the dolpins. "SunDiver" had a scene of a human in a dolpin suit, but only swimming. IMHO one of the best current authors.

Check out Larry Nivien short story "Bigger than Worlds" in "A Hole in Space". It starts at a colony ship, then ends with covering over a galaxy and filling it with air. Then people just swim around (Maybe using those suits).