Yes, artificial gravity has been invented, in that a pseudo-gravitational acceleration can 'easily' be achieved by using a rotating spacecraft. One just needs to have v^2 / r = omega^2 times r = g, where v is the linear speed at the distance r from the spin axis, or use omega (the angular speed of rotation). Unless r is large (i.e. a big spacecraft) different values of g may result for your head and your feet.

To see a fictional (but scientifically-realistic) representation of artificial gravity generated in this way, see the various circular, spinning spacecraft in the movie “2001: A Space Odyssey”.

Pseudo gravity can also be simulated by constantly accelerating at 1g, with the difference that bodies indeed "fall" to the ground, while a rotating spacecraft will create a pseudo-gravitational pull for those bodies in contact with the surface. Obviously, that requires engines with extremely high specific impulse and a lot of fuel, but it could travel in a brachistochrone trajectory, constantly accelerating at 1g for half the trip, then turning around and decelerate at 1g for the remaining half.

The 2001 space station is a good example, but quite far-fetched. For an example of something more in line with current space exploration capabilities, the spaceship in Mission to Mars -- a terrible movie -- is very well done. The Constellation inspired ship in the TV series Race to Mars is also a good example. There's a scene where one of the characters explains how it works to the audience by putting water in a bucket and spinning it around.

How does artificial gravity work then? Simple. It uses the slightly lesser forceful chiral graviton. We'll then develop an Anti-G ray & shoot it at people so they can fly. Women's racks and men’s balls won't sag anymore. Inflation will be conquered as prices won't ever be able to rise again if we shoot them with the Anti-G. And, we can shoot it as the normal G-ray again at any pesky asteroid that pretends to ram us head on and force it backwards, or keep a mini-ray in your pocket and shoot it at that foxy vixen over by the lunch counter. Forget girls not being attracted to you anymore.

Every time I read something more about Einstein, I wonder again how on earth he was able to conceive of all that he did 100 years ago while working in a Swiss patent office. Seriously, how? More to the point, why wasn't he bloody working when he should have been? It's the equivalent today of spending the afternoon 'researching' on the Internet...Of course, this was the pre-Facebook era, and people got a lot more things done. Try to do what Einstein did on the job these days, trying to think through a problem and come up with a genuine solution, and you risk being fired. Some things have changed and not for the better.

One of the books I used in college back in the day, especially in terms of GR, with a special emphasis on Tensor Geometry. After all these years still worth having it in my personal physics library, because the amount of bullshit coming out as pop-physics in the science publishing industry is flabbergasting... ( )

The Best, June 1, 2000
By
Alessandro (Italy) - See all my reviews

This review is from: Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity (Hardcover)

I greatly appreciated this book when I was a student. The tensor analysis is very carefully explained; in addition, you really get a basic physics understanding. The equivalence principle and Mach-Einstein theories discussions are simply wonderful. Of course, some experimental data are too old now to be taken seriously.

Excellent treatment of GR - written for a physicist, March 16, 2004
By A Customer

This is one of the finest GR books that is written for a physicist. Although it is slightly dated, it can still be profitably used today to learn the foundations of the subject that no other contemporary text has explained so clearly.

There is a strong emphasis on the equivalence principle in the book, and many interesting illustrations of this principle can be found throughout the book. There's no discussion of black holes, of course, since the book hasn't probably been revised since its publication in the early seventies. However, Weinberg's book can be truly judged based on the brilliant presentation of the physical ideas of GR in a way that is so familiar to the physicist. A mathematically minded physicist who cares little about real physical insights will be obviously disappointed by this book.

A book based on the physics, not the mathematics, August 5, 2002
By
marcvg "marcvg" (MA USA) - See all my reviews

After a completing graduate school, I decided it was time to learn GR on my own. I got Weinberg's book, and, at first reading, I was put off by it--there are effectively no diagrams, no problems, and no pedagogy. So on to Misner, Thorne, Wheeler. Well these kings have no clothes: MTW contains almost no clean, declarative sentences and could be reduced to 1/4 its size with straightforward editing. So I bought B. F. Schutz's book read it, and and went back to Weinberg's book. With both in hand, I am acquiring a satisfying understanding of GR. And I now realize that Weinberg's book is a masterpiece. As in all his texts, Weinberg's passion is to expose the underlying logic of the physics. All follows from the Equivalnce Princple, and this view gives his book a logic coherency that other's lack. (Try seeing where the Equivalence principle fits in Schutz's presentation.) One criticism: I believe that Weinberg was writing a text for his peers to set them straight about GR; he neglected students. It would have been great if he could have included a mathematical appendix or two to make the text more accessible. But even so, it is a wonderful book. ( )