| Author |
Message |
Oliver
Thought Maker
Joined: 28 Feb 2004
Posts: 6096
Location: Antwerp, Belgium
|
 Mon Apr 12, 2004 1:23 pm Freeman Dyson's Sphere |
|
Freeman Dyson originally proposed the Dyson sphere (or Dyson shell) in 1959. Dyson studied mathematics and later became a professor in physics.
The Dyson sphere is an artificial sphere the size of a planetary orbit. The sphere would consist of a shell of solar collectors or habitats around the star, so that all (or at least a significant amount) energy will hit a receiving surface where it can be used. This would create a huge living space and gather enormous amounts of energy. We have seen such a sphere in the The Next Generation�s sixth season episode �Relics.�
So the Dyson sphere is like an eggshell, completely emptied and assumed to be a perfect sphere. In the center, there would be a star that represents the Sun.
I�ve got many questions and thoughts on this one. When you would be able to stand inside such a sphere, you would not experience any gravitational pull, independently of the thickness of the shell. So it would be extremely difficult to live a life, as we know it. We would be forced to live on the outside of the shell, facing space and not the Sun.
Question 1: How thick would the shell have to be in order for us to experience a gravitational pull as we feel here on Earth?
Question 2: Could we induce a fictitious gravitational pull by spinning the sphere round in order to have gravity on the inside of the sphere? How fast would it have to spin?
Question 3: If we did have gravity on the inside, what would the sky look like? Dark due to the extreme distance or completely lit?
Question 4: How much material do we need to create such a sphere? Is there enough matter in our Solar system?
|
|
|
EnsignParis
Lieutenant Commander
Joined: 07 Sep 2001
Posts: 257
|
| Thu Apr 15, 2004 10:42 pm |
|
| Quote: |
Question 1: How thick would the shell have to be in order for us to experience a gravitational pull as we feel here on Earth?
|
It's not necessarily how thick it has to be, but moreso how much mass there has to be. An incredibly dense neutron star isn't much bigger than Earth, but has a much higher gravitational pull than our it.
But under normal circumstances, it would have to be REALLY thick, and most likely we would have to get our gravity from an artificial source.
| Quote: |
Question 2: Could we induce a fictitious gravitational pull by spinning the sphere round in order to have gravity on the inside of the sphere? How fast would it have to spin?
|
Possibly. Not too sure on that.
| Quote: |
Question 3: If we did have gravity on the inside, what would the sky look like? Dark due to the extreme distance or completely lit?
|
Now, lets take our solar system for example. We are 93 million miles (approximately) away from our Sun. If we built a complete Dyson sphere the size of our orbit around our sun, there would obviously be enough light to reach us, and light our surroundings, if it wasn't blocked by anything, such as the gigantic shell around the sun.
We would probably get light from an artificial source, and the sky as you know it probably wouldn't be quite the same.
| Quote: |
Question 4: How much material do we need to create such a sphere? Is there enough matter in our Solar system?
|
I heard that there is enough material in our solar system to create one, but that would involve harvesting all of Jupiter I believe, and probably even more planets for raw materials.
In my humble opinion the idea of a giant shell covering a star is an insane idea, and in no way is something so incredibly big is cost effective.
I'm compelled to do the math to see how big this shell would actually be, but finding the surface area of a sphere by only knowing the radius is something I would have to look up how to do, and I don't feel like it.
Anyways. we're doin pretty well on this tiny little rock, and has been the past few million years. We don't need something billions the size of it to survive.
It's a stupid idea to build one.
|
|
|
Tsuki no Hikari
Ensign, Junior Grade
Joined: 12 Feb 2002
Posts: 41
|
| Fri Apr 16, 2004 4:33 pm |
|
A Dyson's Sphere would probably be more possible if it were built around a smaller star in an orbit much closer.
Using a radius of 93 million miles from the sun, and just using the surface area of a sphere, the total area of an Earth orbit Dyson's Sphere would be 108,686,539,443,592,486.8 square miles. However, a complete sphere wouldn't be realistic if we have no artificial source of gravity. Applying rotation to the sphere would only give a habitable area not far from the equator of the spin. It wouldn't be very far from it that the pull would be at a fairly decent angle away from straight down. If a Dyson's Sphere were possible, artificial gravity or ultra dense materials would need to be used.
|
|
|
Hyper
Ensign
Joined: 07 Apr 2003
Posts: 60
Location: UK
|
| Wed Jun 16, 2004 6:44 pm |
|
You could pull it off. The sphere would have to be spun on x and y axis at the desired velocity. And yes it would work! Think about it! Pick a point and the resolution of the X, Y axis roational forces will always be the same, no matter where you are. As far as actually building it goes... I mean what about the van allen belt? If you filled it all with atmosphere it would be loads loads hotter. Obviously, it would be light all the time (the blueness in our sky is light refraction) and you could harvest 100% of the energy of the star making it incredibly efficient. As for a neutron star, I think a pencap full weighs as much as the earth. Thats pretty dense isn't it?!
Last edited by Hyper on Fri Jun 18, 2004 7:51 pm; edited 1 time in total
|
|
|
Defiant
Fleet Admiral
Joined: 04 Jul 2001
Posts: 15946
Location: Oregon City, OR
|
| Fri Jun 18, 2004 5:35 am |
|
Freeman Dyson was giving a lecture in my town, and I had the chance to go FOR FREE. I was so super pissed off when I couldnt go, you dont even know. This would be a very interesting topic to hear about.
|
|
|
starnova
Commodore
Joined: 26 Aug 2004
Posts: 1544
Location: Commodore on the USS Farraget
|
| Tue Aug 31, 2004 11:34 pm |
|
that would be a momument a gaint sphere around the sun. 
|
|
|
webtaz99
Commodore
Joined: 13 Nov 2003
Posts: 1229
Location: The Other Side
|
| Wed Sep 01, 2004 7:24 am Re: Freeman Dyson's Sphere |
|
| Oliver wrote: |
So the Dyson sphere is like an eggshell, completely emptied and assumed to be a perfect sphere. In the center, there would be a star that represents the Sun.
|
Do some reading and you will find that Dyson later clarified his concept. The "sphere" would actually consist of discrete habitats at a constant radial distance from the Sun, not an actual shell.
| Oliver wrote: |
Question 1: How thick would the shell have to be in order for us to experience a gravitational pull as we feel here on Earth?
|
This depends on the materials used, but would be somewhere between half and double the Earth's diameter.
| Oliver wrote: |
Question 2: Could we induce a fictitious gravitational pull by spinning the sphere round in order to have gravity on the inside of the sphere? How fast would it have to spin?
|
The problem is that the spin would produce some amount of "gravity" at the "equator", but none at the poles. This would induce enormous stresses in the overall structure. As far as the speed, I am sure you could find the equations somewhere on the Web.
| Oliver wrote: |
Question 3: If we did have gravity on the inside, what would the sky look like? Dark due to the extreme distance or completely lit?
|
That's a tough one. Obviously if the "shell" was not air-tight, the "sky" would look like a cloudless night, but with the other side of the "sphere" as a backdrop instead of the stars. If the "shell" held an atmosphere, I wonder if any light would even get to it. Notice how weak the Sun looks right at sunrise or sundown; that's from less than 100 miles worth of atmosphere.
| Oliver wrote: |
Question 4: How much material do we need to create such a sphere? Is there enough matter in our Solar system? |
The bottom line here is yes, but only if you have really "cheap" (in terms of energy) transmutation of matter.
All in all, the Dyson sphere is an intriguing concept, but ultimately an impractical one. Given the amount of energy and technology required, the return on investment is highly questionable.
-------signature-------
"History is made at night! Character is who you are in the dark." (Lord John Whorfin)
|
|
|
starnova
Commodore
Joined: 26 Aug 2004
Posts: 1544
Location: Commodore on the USS Farraget
|
| Wed Sep 01, 2004 9:54 pm |
|
but how would you build it and get close to the sun?
|
|
|
webtaz99
Commodore
Joined: 13 Nov 2003
Posts: 1229
Location: The Other Side
|
| Thu Sep 02, 2004 7:21 am |
|
The idea is that this thing would be BIG. Like the size of Earth's orbit.
As far as how you build it, better ask Mr. Dyson.
-------signature-------
"History is made at night! Character is who you are in the dark." (Lord John Whorfin)
|
|
|
starnova
Commodore
Joined: 26 Aug 2004
Posts: 1544
Location: Commodore on the USS Farraget
|
| Mon Sep 06, 2004 2:49 am |
|
i wondor if it will ever be built? 
|
|
|
Five - seveN
Rear Admiral
Joined: 13 Jun 2004
Posts: 3567
Location: Shadow Moon
|
| Mon Sep 06, 2004 4:52 am |
|
| starnova wrote: | | i wondor if it will ever be built? |
Probably not, and if it would be built, it would be in small colonies, like webtaz said. There simply isn't enough matter in the solar system to make the sphere so thick that it'd neutralize the gravity of the sun.
|
|
|
webtaz99
Commodore
Joined: 13 Nov 2003
Posts: 1229
Location: The Other Side
|
| Mon Sep 06, 2004 1:16 pm |
|
We are much closer to sustained fusion than most people believe. And there are other ways to use nuclear power without the dangers and waste problems associated with U235. The Dyson sphere was all about capturing the Suns energy. Before we have the ability to make one, we will no longer have the need for it.
-------signature-------
"History is made at night! Character is who you are in the dark." (Lord John Whorfin)
|
|
|
Morphy
Forum Ogre
Joined: 15 Jun 2001
Posts: 3858
|
| Tue Sep 07, 2004 5:11 am Re: Freeman Dyson's Sphere |
|
| Quote: | | Question 1: How thick would the shell have to be in order for us to experience a gravitational pull as we feel here on Earth? |
If the shell is made out of the same thing Earth is made out (which it wouldn't be), then I would say less than Earth's diameter, which is about 16,000 miles (?). Assuming it is made out of material more dense and greater mass than "dirt", the thinkness would be less.
| Quote: | | Question 2: Could we induce a fictitious gravitational pull by spinning the sphere round in order to have gravity on the inside of the sphere? How fast would it have to spin? |
I've seen something like this in a movie, but I just can't imaging how this would work in our Dyson sphere scenario.
| Quote: | | Question 3: If we did have gravity on the inside, what would the sky look like? Dark due to the extreme distance or completely lit? |
It would be lit all the time.
| Quote: | | Question 4: How much material do we need to create such a sphere? Is there enough matter in our Solar system? |
No, there would not be enough material in our solar system.
|
|
|
starnova
Commodore
Joined: 26 Aug 2004
Posts: 1544
Location: Commodore on the USS Farraget
|
| Mon Sep 13, 2004 10:22 pm |
|
if one was ever built how long would it take just to mine the stuff and build it?
|
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2002 phpBB Group
Star Trek �, in all its various forms, are trademarks & copyrights of Paramount Pictures
This site has no official connection with Star Trek or Paramount Pictures
Site content/Site design elements owned by Morphy and is meant to only be an archive/Tribute to STV.com
|
Search
FAQ
Log in
