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Solar System in a Can May Reveal Hidden Dimensions
dylanduck writes "A model solar system, made of tungsten and placed in space, could reveal hidden spatial dimensions and test alternative theories of gravity. If the system's 'planets' moved slightly differently to the way predicted by standard gravity, it would signal the presence of new physical phenomena." From the article: "Once at the Lagrange point, the artificial solar system would be set in motion inside the spacecraft. An 8-centimetre-wide sphere of tungsten would act as an artificial sun, while a smaller test sphere would be launched 10 cm away into an oval-shaped orbit. The miniscule planet would orbit its tungsten sun 3,000 times per year."
A tungsten sphere 10cm in diameter would have such a tiny gravitational field that I suspect even a hydrogen atom at the ambient temperature of local space would possess escape velocity.
What exactly are they thinking of putting into orbit around this thing?
They mentioned that would have to be taken into account. Scientists measure the gravitation attraction between human scaled objects on Earth all the time, yet that's dwarfed by Earth's gravity.
The key question is: What is the ratio between signal and noise here? The article does not mention this at all except talking about lagrange points, solar wind, etc. I assume placing it at L2 is to get the S/N ratio >1.
This fails when considering some noise sources:
1. Accelleration felt by a "grain sized planet" due to a 5kg ball 10cm away is 1m/s/year.
2. Acceleration felt by same "planet" due to moon 1 million kilometers away: 130 times more
3. Accelleration felt due to spaceship: ?
4..? L2 orbit itself, light pressure, magnetic & other fields etc
This appears unfeasable by orders of magnitude.
I do not have much faith in statments like "Gravity leaks into other (higher) dimensions." Where does this come from? Efforts to make string theory models fit the real world?
"Fix it"
You have to understand that to a theoritician, having a "basis in reality" is a vague phrase. We have these equations, and they work really well for certain things that have been troubling the physics community for quite some time. They happen to require more than 4 dimensions. The theoretician says, "Oh well, find the other dimensions!" It's not a strange concept to make up new physics to "make the math work out". Quarks were hypothesized, then as each quark pair was discovered, we knew how many pairs of quarks there should be and knew roughly where we needed to look for the rest of them. You could say someone "made up" the top quark to "make the math work". But it turns out that it worked pretty well. Also, don't even get me started about the Schrodinger equation... ever seen the derivation? Yeah... it's more of a "here's a couple theoretical ways the equation _could_ be derived... maybe...
Since we're not able currently even to build a spaceship capable of making it to the moon (having mothballed all the relevent tech and gone for the technical nightmare that is the shuttle, and the hidiously expensive disaster that is the ISS), why bother with these types of experiments?
Such experiments, while useful, aren't practical when we have a real and current need to figure out how to get construction workers and ordinary people into space, so we can build a realistic presence there.
Once we're there, we could perform experiments like this at a fraction of the cost.
Ok, perhaps I'm thinking too fancifully, but it's real concern. Let's face it, every environment we've moved into only becomes liveable when the ordinary people who know how to build stuff and make things arrive. The larger the number of people, the faster things progress.
So long as it's only scientists and the 'elite' going into space and performing experiments progress will be very slow. That can't be good.
What we need is people going 'prospecting' for interesting asteroids/orbiting 'junk' that can be exploited, building commercial stations, setting up routine flights into space. In short, we need economic forces active in space.