Space Elevators

Discussions on scientific and technological advances, both old and new.

Re: Space Elevators

Unread postby HalloweenWeed » Mon Dec 06, 2010 5:31 am

LeeShane wrote:A new space shipping system being urbanized could make travel to Geostationary Earth Orbit (GEO) a every day event and make over the global financial system.

Interesting. Welcome to our forum LeeShane. We hope you will return to chip in more like this in the future.
"Religion is just mind control." "Atheism is a non-prophet organization." - George Carlin
"If God existed, why would he care about any of the us fools contributing to the end of the earth as we know it?" - HalloweenWeed
User avatar
HalloweenWeed
 
Posts: 435
Joined: Sat Jun 06, 2009 3:22 am
Location: Maine, USA
Reputation point: 1989

Re: Space Elevators

Unread postby Azmodan Kijur » Tue Feb 22, 2011 7:16 pm

Such a system might make mining the moon for He3 a viable option to using Hydrogen in proposed fusion reactors.
Azmodan Kijur
Chat Moderator
Chat Moderator
 
Posts: 290
Joined: Sat Jun 06, 2009 11:29 pm
Reputation point: 2055

Re: Space Elevators

Unread postby HalloweenWeed » Wed Feb 23, 2011 1:24 am

Hmm, consider the earth like a ballerina or ice skater spinning freely in space. What happens to a ballerina spinning when she pulls in her arms and legs, nearer to the axis of rotation? Her rotation speed increases. The opposite is also true. Now consider the scenario where we have hundreds of these space elevators, each with hundreds of tons of materials in space. Could this have an effect on the speed of the earth's rotation? Now I am not saying that it would change by an hour, nor even a minute. Perhaps a few seconds. But what effect might this have on our climate? Might it be possible that it could have disastrous effect?


While I am talking about this subject, this reminds me of another thing related to this that I wonder about. We have launched thousands of tons of rockets (into space), and the vast majority of these launches were done in the daylight. Each one of these launches involved rockets blasting pressure at the earth, a force putting pressure on the earth as well as the rocket. Sure, it is a short-lived force, perhaps for less than one minute per launch, but multiply this by all the launches. Since the vast majority were done in daylight, the force against the earth was always pushing the earth away from the sun! Could this eventually alter our orbit around the sun? Perhaps cause the earth to start moving away from the sun? When we find out, it may be too late to correct it.
"Religion is just mind control." "Atheism is a non-prophet organization." - George Carlin
"If God existed, why would he care about any of the us fools contributing to the end of the earth as we know it?" - HalloweenWeed
User avatar
HalloweenWeed
 
Posts: 435
Joined: Sat Jun 06, 2009 3:22 am
Location: Maine, USA
Reputation point: 1989

Re: Space Elevators

Unread postby Azmodan Kijur » Wed Feb 23, 2011 3:55 am

Wow, my machine must have posted just part of my intended response last night. Don't doubt that was confusing to some. But I will flesh out the answer now for you, HW. :)

As far as I am given to understand, the force inherent in the rocket, while immense to you or I and enough to escape the gravity well, has to be greater than 9.8 m/s2 just to resist gravity, let alone fight it off. 9.8 m/s2 is the same as approximately 127,000 km/h2 - pretty fast really. Anyway, to get off the ground, we can state that a rocket needs to exert at least more than 9.8 newtons of force per kilogram. If the rocket is 10 tonnes (metric), then we need it to exert at least 9.8 x 10,000 kg = 980,000 newtons of force.

Earth is approximately 6,000,000,000,000,000,000,000,000 kilograms (6^24). The force of the rocket is to lift 10,000 kgs - there is a big gulf there in the size of the forces. But it does have an effect - just an incredibly small one. Now, that said, we have to remember that the planet is in orbit of Sol - orbit is a stable condition where our revolutions around the local star are on a relatively fixed path. This means that small changes in the position of the planet are actually corrected as it orbits. Basically, we'd need to apply enough force to knock the planet out of its current orbit into a new one. The force that this would take is rather extreme given the weight of the planet and the forces involve (gravitational well of Sol, the speed of the planet, etc).

Suffice it to say that, no matter the number of times we blast off from this planet - we are incapable of changing the position of the planet in any meaningful way. A space elevator would be similar - the entire surface would likely need to be brimmed with elevators to create the potential for any changes.

Oddly, this is one of those scale problems regarding the universe. Media has done a piss-poor job of imparting the actual scale of the universe at large and of the materials and distances within it. Earth is 6 yotta kgs in weight - that is simply staggering. The earth is an average of 1 AU from Sol - that's about 149,597,870.7 kms! Light takes 8 minutes to go from the sun to us due to that distance. 149.5 million kms ... the diameter of the planet is only 40,000 kms - stretch out earth and lay it flat ("equatorially" speaking) and you would need 3,739 earths to cover that distance. Our closest neighbour is Proxima Centauri is 4.2 light years from us. Only 4.2. That's at the speed of light. That equates to 39,707,870,813,049.6 kms. 39.7 Trillion kms. Again, for reference, our planets circumference is only 40,000 kms. Light takes 4 years to go from here to there. If you could travel at superluminal speeds, then a round trip would take almost 9 years. And due to relativity, time would dilate for the traveler, meaning it would be a significantly shorter trip for them. Meaning they could leave earth at age 25, go to Proxima and return (8.4 year journey) and not have aged 8.4 years in the process (probably only 1 for example). You could go as the oldest among your siblings and return as the youngest. Boggles the mind.

For the rockets, no doubt we are quite powerful to do what we do. But we are gnats along side the most casual of conditions in the universe. A yawn on the galactic or even solar (hell, even the planetary) scale.
Last edited by Azmodan Kijur on Wed Feb 23, 2011 1:16 pm, edited 3 times in total.
Azmodan Kijur
Chat Moderator
Chat Moderator
 
Posts: 290
Joined: Sat Jun 06, 2009 11:29 pm
Reputation point: 2055

Previous

Return to Science and Technology



Who is online

Users browsing this forum: No registered users and 1 guest

[Valid Atom 1.0]