The possibility of the Death Star

Lbeard

The Star Wars Death Star.

Would it be possible or would its' own gravity make the thing collapse?

On the web its' diameter is given as 160km.

Capt'n Midnight

Don't forget
it's hollow so much lighter
it's constructed of stuff that's stronger than rock and rubble that most small moons are made of
in the Star Wars universe even the smallest space ships can have artificial gravity so they have advanced technology

Lbeard

Capt'n Midnight wrote: »

Don't forget
it's hollow so much lighter

Considering for a moment, it's not in the Star Wars universe - and gravity behaves like we'd expect it. In what way would it have to be constructed? Would it need spines coming from its' core, and then the rest of the structure suspended on those spines? Those spines would need to be 80km.

it's constructed of stuff that's stronger than rock and rubble that most small moons are made of

Yes but moons are solid. I think the deepest mine on earth is 8km. The pressures become immense. I think if you dug a mine on the moon, even though the core is not molten, at a certain point the moon rock would flow like treacle and close the mine.

in the Star Wars universe even the smallest space ships can have artificial gravity so they have advanced technology

Even as a small child, I knew there was something not quite right about Star Wars gravity. Similarly in Star Trek. The people are always standing perpendicular to where I would expect the line of gravity to be - as if they were on a ship at sea, and not a ship in space.

What do you think their magical gravity making device is? How does it overcome the gravity of the structure?

If you could create local gravities of 1G, you might be able to build a huge structure and not have to worry about the overall gravity, because at local points the floors may only experience the same strain as if they were one story structures on earth.

Capt'n Midnight

At the very centre gravity cancels out

as you move further out it gets stronger - so there isn't a lot of weight in all that mass

earth has a surface gravity of 1g

it's a LOT bigger, and it's a lot denser so you put in guesstimates to get the surface gravity , and then compare that to large structures on earth, not forgetting that our structures are self supporting towers rather bridges or spoked wheels and subject to wind and weather on a cantilever

Lbeard

Capt'n Midnight wrote: »

At the very centre gravity cancels out

as you move further out it gets stronger - so there isn't a lot of weight in all that mass

The gravity gets weaker but the pressure bearing down from above gets stronger.

then compare that to large structures on earth, not forgetting that our structures are self supporting towers rather bridges or spoked wheels and subject to wind and weather on a cantilever

The Death Star would need supporting towers too. I imagine they would need to point into the centre of gravity, like supporting towers on earth.

I don't know how much the Death Star weighs. I know the radius is 80km. Therefore the supporting towers would need to be 80km - we do not have any comparable structure on earth like that.

The tower needs to be strong enough to support its' own weight, plus whatever structure is suspended from it.

Capt'n Midnight

Lbeard wrote: »

The tower needs to be strong enough to support its' own weight, plus whatever structure is suspended from it.

With a bicycle wheel the rim is in compression and the spokes are in tension

mr lee

dont forget ,the death star also had the power of the dark side

Lbeard

Capt'n Midnight wrote: »

With a bicycle wheel the rim is in compression and the spokes are in tension

It's a different concept. With a bicycle wheel the gravity is all in one direction - so at any one time only some of the spokes are in compression, the rest are in tension.

Squeaky the Squirrel

At a cost of $850,000,000,000,000,000 to build it, we'll never know.:pac:

Capt'n Midnight

Lbeard wrote: »

It's a different concept. With a bicycle wheel the gravity is all in one direction - so at any one time only some of the spokes are in compression, the rest are in tension.

No they are all in tension. You could use string.



if you have a wall thickness of less than 20:1 then it's like a tube and all the circular strength stuff applies.


or since they can breath air there then it could be a balloon with 100Kn supporting the "roof" ( one stone / square inch in old money )

Lbeard

Capt'n Midnight wrote: »

No they are all in tension. You could use string.

The tension is to redistribute the strain around the wheel?

Is this an engineering text book thing?.....Would you have a link with some diagrams and maths etc?

In the steel construction of a skyscraper, the core support takes all the stress of itself and the building. The individual floors are then suspended from supports that transmit that stress to the core.

if you have a wall thickness of less than 20:1 then it's like a tube and all the circular strength stuff applies.

I know it's mostly empty - but it's 160 km in diameter. Circular strength?

Do you recommend any good engineering reading?

or since they can breath air there then it could be a balloon with 100Kn supporting the "roof" ( one stone / square inch in old money )

As far as I am aware, jumbo jets depend on the internal pressurisation, not only so people can breath, but also for their structural integrity.

I do like the idea of an inflatable space station.

Might the death star be a Buckminster Fuller ball?

amen

If you could build how it would you arrange the floors ?
Arbitrary top to bottom ?
in a circular pattern radiating from the centre out ?

Capt'n Midnight

you could start off with a balloon and move in the skeleton in very low g and then fill in the rest

https://en.wikipedia.org/wiki/Project_Echo

FirstinLastout

Capt'n Midnight wrote: »

No they are all in tension. You could use string.

QUOTE]

When in actual use only 1/2, if even, of the wheel's spokes are supporting the weight of the rider and/or bicycle.
Spokes don't work under compression, under which the lower 1/2 will be in.
These supporting forces are being transfered from spoke to spoke as the wheel rotates.
A spoked wheel pretty much acts in a 2d plane whereas the Death Star would be 3 dimensional.

Capt'n Midnight

FirstinLastout wrote: »

When in actual use only 1/2, if even, of the wheel's spokes are supporting the weight of the rider and/or bicycle.
Spokes don't work under compression, under which the lower 1/2 will be in.
These supporting forces are being transfered from spoke to spoke as the wheel rotates.
A spoked wheel pretty much acts in a 2d plane whereas the Death Star would be 3 dimensional.

http://autobus.cyclingnews.com/tech/fix/?id=tm_1

Rim manufacturers have set tension recommendations from as low as 80 Kilograms Force to as high as 230 Kilograms force.

multiply that by 36 spokes and the load on the rim is a couple of tonnes


The whole point is death star is not the same as an unsupported tower
tension is important
air pressure is important
if you spin it then you can get gravity that way and it's most definately not a tower

Dr Silly Bollox MD

What Would It Take to Build a Death Star?

just what it would take to the build the Empire's Death Star using only the Automated Transfer Vehicle robot cargo ships built by the European Space Agency. The answer: We'll have to wait a LONG time for anything like the Death Star.

According to Allain (you can read the full post here), if humanity collectively turned to the Dark Side and opted to build the Death Star in 10 years, it would take four ATV launches EVERY SECOND to do it. If we launched one ATV a month, it would take more than 5 billion years, Allain says. So basically, the sun (and likely Earth) would be ancient history before our Death Star would be ready to take out the Rebel Alliance. The ATV is one of several cargo ships supplying the International Space Station. They are large and cylindrical and can carry about 7,200 kilograms (15,873 pounds). The next one, ATV-4 Albert Einstein, is launching on June 5.

ScumLord

In a few more years we could have access to cheap carbon based materials like graphene or carbon nanotubes.

That could be used to build a super light and giant rigid ship on that scale. We could probably send up a ship that could print the thing out.