Artificial Gravity Concepts
I wanted to share some artificial gravity concepts.
Natural Gravity
The best gravity would be natural gravity. What if we took engines and fuel and strapped them to a very large mass (ice, rock, or ballast metal)?
To get a modest 1/10th gee (1 m/s/s), we'd need :
- a water ice (1 g/cm^3) block 3,750 km in diameter and massing 2.1E+23kg
- a uranium block (19 g/cm^3) 200 km in diameter and massing 1.4E+20kg
- an osmium block (22 g/cm^3) 166 km in diameter and massing 1E+20kg
- an electron-degenerate block (6x10^14 g/cm^3) 4 millimeters thick and massing 36 million tons (3.67x10^17 kg) with one-gee @ 0.5 meters from the plate
So, there is an advantage to using denser material: you need less of it.
Accelerated Mass
What if we took less mass, but accelerated it in a ring collider to relativistic velocities to boost it's mass?
CERN says they can get a beta of 0.5.
That would reduce our base mass down to 5E+19kg, (which isn't much) and the mass energy required to do it is about the same amount of mass in matter+antimatter.
Boosted Mass
What if we changed the value of the Higgs field? Gluon-gluon fusion is the primary way of generating Higgs quanta, but all we need to do is modify the value of the Higgs field.
If I have this right, doubling v doubles mass: W_mu+/- = gv / 2.
A rough estimate of the energy used by the Large Hadron Collider to produce Higgs bosons is 13 TeV, or about 2 microjoules per encounter.
Obviously, it took more power for LHC to get there: an estimated 500 megaWatts.
But this is far better than planet-masses of antimatter.
Direct Graviton Production
The most energy efficient way would be to somehow produce gravitons (if they exist) directly. This would get the energy cost of artificial gravity down to (hopefully) the minimum : P = mass x gee (or 9.8 kiloWatts per ton).
3 answers
On your suggestions
Natural gravity
Works, of course. But needs a lot of energy to accelerate towards your destination.
Accelerated mass
While a ring collider can accelerate particles to very high speed,the total mass of those particles is negligible to the mass of the collider itself. Also, the fact that it is in form of a ring means you'll not get the same total gravitational pull as you would get from a sphere of the same mass. Basically, the mass is distributed too far.
Also, with the size of the LHC, you'd only need to rotate that ring very slowly to get artificial gravity by centrifugal force. So if you would build such a gigantic ring structure in space anyway, you might as well go that way. Then the ring could house your astronauts instead of an accelerator.
Boosted mass
The vacuum value of the Higgs field is determined by its self-coupling. If you can modify that, you probably have the technology to modify any coupling constants, and thus effectively can change the behaviour of matter however you want.
Direct graviton production
Producing real gravitons means producing gravitational waves. That's not what you want. You want a source of virtual gravitons, i.e. of the gravitational field. Unfortunately, the only known source of the gravitational field is a large mass.
Alternative ways (not new, but known to work):
Rotation
The centrifugal force (no discussions about centrifugal vs. centripetal force at this point, please) will simulate the gravitational pull. If the radius is large enough, you'll not notice the difference.
Acceleration
When accelerated, the acceleration itself will act the same as a gravitational pull. This is actually the foundation of General Relativity. As a bonus, at the same time the acceleration will bring you closer to your destination.
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This is a very interesting set of ideas. Here is some maths to ponder: To find the surface gravity of a world made of exotic materials...
(average density [g/cc] X Radius [km]) / 35000 = G [Surface Grav]
The answer for Earth is 1.0 G
Let's try Osmium --
22.6 g/cc X 1500 Km / 35000 = 9.7 Very close to Earth's surface grav, but one fourth the radius.
-Molly
- The 35000 is a conversion constant derived from the universal gravitation constant and the arbitrary Earth G of "one".
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Depends on what you want to do with it.
Gravity, by theory of general relativity, requires mass—to show any notable effect, a huge mass—that won't magically appear at a finger snap (and more, won't disappear at a second snap).
A tractor beam, the kind that is used in Star Trek movies, is more likely to work. Current technology works only on a nano-scale, moving single atoms around in a vacuum. And I don't even understand how this works.
Pushing things away is far easier.
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