# Force fields; are they possible? **URL:** \ **Category:** Factual Questions\ **Created:** [March 11, 2003, 12:33am UTC](https://boards.straightdope.com/t/force-fields-are-they-possible/160447 "2003-03-11T00:33:02Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![tonbo0422](https://avatars.discourse-cdn.com/v4/letter/t/b5e925/32.png) [@tonbo0422](https://boards.straightdope.com/u/tonbo0422)\ **Post date:** [March 11, 2003, 12:33am UTC](https://boards.straightdope.com/t/force-fields-are-they-possible/160447/1 "2003-03-11T00:33:02Z")
Okay, so Cecil has shot down colonising the planets. But is a force field, ˆ la Star Trek, actually possible without incinerating someone trying to get through it? I mean the old-fashioned kind that gives you a light buzz when you brush up against it. Surely the armed forces are working feverishly on such a project. ---
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [March 11, 2003, 12:53am UTC](https://boards.straightdope.com/t/force-fields-are-they-possible/160447/2 "2003-03-11T00:53:42Z")
[http://www.straightdope.com/mailbag/mforcefield.html](http://www.straightdope.com/mailbag/mforcefield.html) ---
**Author:** ![tonbo0422](https://avatars.discourse-cdn.com/v4/letter/t/b5e925/32.png) [@tonbo0422](https://boards.straightdope.com/u/tonbo0422)\ **Post date:** [March 11, 2003, 4:05am UTC](https://boards.straightdope.com/t/force-fields-are-they-possible/160447/3 "2003-03-11T04:05:37Z")
Hmm, did a search and that thread didn’t show up . . . thanks. ---
**Author:** ![kniz](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@kniz](https://boards.straightdope.com/u/kniz)\ **Post date:** [March 11, 2003, 4:23am UTC](https://boards.straightdope.com/t/force-fields-are-they-possible/160447/4 "2003-03-11T04:23:08Z")
[ul]Try [**this**](http://www.wired.com/news/technology/0,1282,54641,00.html)[/ul] ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [March 11, 2003, 4:25am UTC](https://boards.straightdope.com/t/force-fields-are-they-possible/160447/5 "2003-03-11T04:25:34Z")
They can float a frog on a sufficiently powerful magnetic field so if they can extrapolate that force in some manner it might be possible to push a human away, but the power needed to do this would be absurd vs using more conventional methods. [Some Levity in Physics](http://www.americanscientist.org/issues/sciobs99/sciobs99-03physics.html) > [@](#): > > Seeing the April 1997 issue of Physics World, a publication of the Institute of Physics in the U.K., many readers chuckled at what they thought was an April Fool’s joke: the report of an antigravity device being used, among other things, to levitate a frog. The appearance of a subsequent notice in a British tabloid, The Sun, probably did little to dispel suspicions of a hoax. > > Yet the scientists involved in the work, led by Andrey Geim of the University of Nijmegen in The Netherlands, were being quite serious when they announced that they had floated a live frog using a powerful electromagnet. That a living creature could be lifted in this manner came as a complete surprise even to many knowledgeable physicists. But the flying frog was merely a demonstration of a fundamental property of ordinary materials – and of a technique now being used to perform “low-gravity” biological experiments that might otherwise have demanded a ride on the Space Shuttle. > > Most everyday materials – including water and living tissues – are weakly magnetic. They are said to exhibit diamagnetism, a slight tendency to become magnetized in the direction opposite to an applied magnetic field. A diamagnetic object placed in an intense magnetic field that is configured to diminish in strength with height will experience an upward force. So the field of a sufficiently powerful electromagnet can balance the downward tug of gravity – at least over a small volume. > > Although materials normally recognized as magnetic (including iron, permanent magnets and so-called paramagnetic substances) can also be lifted with an electromagnet, they cannot hover in midair, unless some feedback mechanism adjusts the surrounding magnetic field constantly to maintain a fixed position. But the levitation of diamagnetic materials is inherently more stable. If the floating diamagnetic object rises slightly, the magnetic force on it diminishes, and it settles back down; if it falls, it automatically gets a boost from the increased magnetic force exerted below its equilibrium position.