The Big Idea

When looking for new homes for the human race, people generally think of worlds like Earth, that is, planets with a solid crust and liquid water oceans, places where plants might grow and animals might be available to eat. Sometimes people expand this to include lifeless moons or perhaps moons or worlds with trapped water, like Ganymede or Mars. But why shouldn’t we consider living on worlds not like Earth at all? Why not gas giants, like Saturn, Uranus, and Neptune? Clearly a planet just like Earth would be a better place to live if your level of technology were in, say, the Stone Age. But with a higher level of technology—hey, even with twentieth century technology—the challenges of a world radically different from Earth, like a gas giant, don’t really pose a problem. Can’t breathe the air? Solve that by living in controlled atmosphere habitats. No solid surface to set down on? Float your giant living habitat on balloons. No plants or animals to eat? Grow or raise your own in y

The term "antigravity" is really the stuff of science fiction rather than a term in common use in the scientific community. As such, it's rather ambiguous and could refer to multiple things. One idea pioneered in a story by H. G. Wells was a substance called "Cavorite," which would effectively block gravity's pull, allowing an object to lift away from Planet Earth (the tale was  The First Men in the Moon ). Other proposals have featured gyroscopes or electrodes or magnetic fields canceling out or altering gravity in a way similar way to Cavorite. Please note there has never been any realistic theory of any means by which a substance could block gravity (though under the right circumstances, magnetism really  can counteract it). Under Einstein's General Relativity, gravity is not really a force at all--its sort of a side effect of the existence of matter/energy, which causes the structure of space to bend...well, more correctly, to compress. Any physical

  (image by author) NASA's Dr. Harold White in a  paper  last year argued that warp drive is realistically possible in terms of the energy requirements to bend space. How a warp drive would work  would be to expand space behind the craft while contracting it in front of the craft (just as imagined in Star Trek). Expansion behind and contraction before would in effect "push" the craft forward. Well, it would create a bubble of space (and time) that would surround the craft and push that forward...the craft within the bubble would never exceed the speed of light and according to the best theoretical knowledge of physics, there is no limit to the speed at which space can be bent--er, "warped"--so this changing of the shape of space could create an effect that would make a vessel travel as if it were going faster than the speed of light. Note that this "warp speed" acceleration would not produce actual inertia, so Jean-Luc Piccard saying "enga