Anti-Gravity and Space Cruisers/Space Ships?

Question

I was watching mythbusters and thwy were testing out the myth of anti grav. I got wondering and said to myself "Would we be able to create an anti grav machine?" The I said "If we did, would we have enough metal to make a space ship let alone a fleet?" My question is, could we make space ships like the Enterprise and could we develop an anti gravity machine?? Speculate. Think hard. The report back. All answers welcome, except ones that are offensive.

Drew

Answer 1

We already have an anti-gravity machine.  It's called a chair.  And the ground.  It works great.  I haven't fallen to the center of the earth yet.  Or you can just hang out in a freefalling reference frame (orbit, vomit comet).

Answer 2

It would seem, that a least for the foreseeable future, captain Kirk and his merry band of warp speed travellers are going to remain confined to the realms of science fiction, fantasy, entertainment!

It might be useful at this point to explore what physicists currently view anti gravity to be!

After publishing his General Theory of Relativity in 1915, Einstein explored the consequences of his gravitational field equation.

G = 8πT

In a paper titled 'Kosmologische Betrachtungen zur allgemeinen Relativitatsctheorie' (Cosmological Considerations on the General Theory of Relativity) published in 1917, Einstein found that to model a steady state universe, which was the then favoured model, he had to bastardise his field equation into the parameterised form: -

G(μν) - λg(μν) = -κ(T(μν) - ½g(μν)T)

Where the constant(?) 'λ' is the cosmological constant or a 'fudge factor' that Einstein introduced to make his field equation work for a steady state universe. When Edwin Hubble discovered, in 1925, that the universe was expanding, Einstein commented that this constant was the greatest blunder of his life. It seems that Einstein ignored the implications, implicit, within his field equation that the universe is expanding!

However, a modern interpretation of this constant is that it represents a repulsive aspect to the gravitational force. The repulse force could be viewed as anti-gravity!

Wikipedia, the free encyclopaedia comments, 'In 1998, observations of type Ia supernovae ("one-A") by the Supernova Cosmology Project at the Lawrence Berkeley National Laboratory and the High-z Supernova Search Team suggested that the expansion of the universe is accelerating'. this acceleration is attributed to the presence of 'dark energy'. However, Wikipedia, the free encyclopaedia further comments, 'The simplest explanation for dark energy is that it is simply the "cost of having space": that is, a volume of space has some intrinsic, fundamental energy. This is the cosmological constant, sometimes called Lambda (hence Lambda-CDM model) after the Greek letter λ, the symbol used to mathematically represent this quantity. Since energy and mass are related by E = mc², Einstein's theory of general relativity predicts that it will have a gravitational effect. It is sometimes called a vacuum energy because it is the energy density of empty vacuum.....The cosmological constant has negative pressure equal to its energy density and so causes the expansion of the universe to accelerate.'

It may be that in the future, with a deeper understanding of gravity or a quantum gravity theory, a 'gravity drive' will become an engineering possibility. However, at present our science and technology cannot conceive of engines of such immense power and so a 'gravity drive' must remain in the preview of science fiction films, books and TV shows.

I hope this is of some help!

Answer 3

The nature of your quandary preposes obvious ridicule which final sentence clearly curtails but that limits an honest answering of the question in scientific sincerity.

Therefore in layman's terms, I think there is enough material to build the ship but to create the hovering effect can not be done by anti-gravity creation per se but a force generation that opposes the effect of gravity.

Answer 4

David's answer is very thorough, and I agree with everything he wrote.  I wanted to add one thing to it though.  There is some speculation that anti-matter and matter would exhibit repulsion, and thus exhibit a form of anti-gravity.  I say some speculation because most scientists believe that anti-matter curves space-time the same amount as matter and exhibit the same force of gravity.

However, as we learn to create more stable anti-matter or perhaps find an anti-matter galaxy in the universe, we'll be able to experimentally verify how gravity works between anti-matter and matter.