Force fields like the ones on Star Trek are most likely impossible. But let’s pretend they’re not for a moment. Let’s pretend that during my latest pan-dimensional [del]raiding trip[/del] shopping expedition I came across tech for force shields that would work under our laws of physics and brought it back to our world. What unintended negative consequences would there be for the release of such technology?
Hmmm. Accidents when people miss the warning sign and walk or drive into an invisible wall?
If we can imagine them, then they’re not unforeseen, no? 
I didn’t want to stink up my OP with details, but let’s assume that the shields are translucent rather than invisible.
The usual threats. I think it’s man-eating-penguins this week.
Well, it could be on while you’re travelling a hillside. Then you slip and fall off an incline and instead of just sliding down a few feet while you grabbed for purchase, you go bouncing on down the 1000 feet of hillside, ricocheting off trees like a pinball, and land in a crevice, trapped and slowly dying in an impenetrable shield because you can no longer reach the “off” button.
How much “give” would they have to them if someone did walk or drive into them? They’d have to have more as the speed at which a possible collision could happen went up, or else people could be seriously injured in collisions. Making them not transparent isn’t going to eliminate the possibility of collisions, either- people and cars collide with non-transparent objects all the time.
Surely you’re familiar with how Unus met his end?
A power outage could result in criminals, dogs, killer bees, and viruses escaping willy-nilly to wreak havoc.
I’m confused–are you envisioning a personal force shield generator, like Querl Dox’s belt, or one attached to a car or bicycle? I don’t understand how the latter works as it would prevent the wheels from making contact with the ground.
I’m not currently willing to admit knowing anything about Unus the Untouchable.
Er…so what? If you throw up a force shield around your business because you’re concerned about people trying to break in through the door, why would you care about what damage the person doing so incurs?
I envision the force shields looking rather like extremely thick, dark, smoky glass…translucent rather than invisible or transparent. They’re no less liable to be seen than a brick wall, in other words. And as long as the operator isn’t turning them on and off recklessly, I don’t see the issue.
Higher consumption of foreign oil to power the things.
Run into one side edge first?
You’d be cut in half.
What about hostage situations?
A person could stash themselves and a few hostages inside a force field/bubble thing and be pretty damn free to make all the demands they want.
The biggest problem, of course, is when somebody shoots one with a lasgun and triggers a massive explosion.
The answer to that would radically depend on what powers the bleeding thing.
Some quirk of physics that allows one to make a bulletproof shield the size of a House that can be run off of a car battery would would certainly change things more than one that required the full output of a nuclear power plant.
You know those old people who drive 30mph in the left lane of a 50 zone? The same ones who accidentally hit the gas instead of the brakes and ram into buildings and crowds?
Imagine those people having possession of force fields.
I don’t want to live in that world.
In Peter F. Hamilton’s Night’s Dawn trilogy (excellent, big books, although he stumbles at the end IMHO), starships’ forcefields are totally, impenetrably black and no radiation can pass through them in either direction. When a starship captain wants to know what’s going on outside, he has to extend sensors through the forcefield on automated, periscope-like poles. Sometimes they got nasty surprises that way.
In the even better The Forever War by Joe Haldeman, there was a small, regimental-scale forcefield for infantry to use. It dampened all energy, so the troops had to wear special insulated spacesuits to work within it. Damage your suit, even just a little bit, and you’d die instantly, as your electrically-based brain functions would abruptly stop. Since no energy weapon worked within it, all of the Earth troops in this distant-future conflict had to be trained in the use of swords, spears and arrows for when the alien enemy’s soldiers tried to enter the forcefield.
Not impossible. Visit the thread on force fields. But they do come withj a set of new challenges. The thing that generates the shields has to be strong and powerful enough not only to support the shield, but also to absorb the impact of whatever force hits the shield.
Or something like that.
What’s to stop people from putting up force-shields around others, without their consent? What if you make a shield around their head that’s slightly smaller than their head? On a larger scale, think “East Germany”, only totally impermeable.
Criminals could set up force-shields to automatically engage as soon as they crossed a specific area. The cops, in hot pursuit, would run into the shield full speed and die.
What happens when you turn on a shield with a very large radius inside the first floor of a tall building with a relatively small radius? Twin Towers, redux?
Can a shield be turned on such that it extends through objects? What happens to those objects? Are they destroyed? What if those objects are people?
How strong are these shields? How hard? How much mass? If you were to drop shield generators from a plane or from space, then activate them after they had fallen some distance (so they’d be harder to detect until it was too late, or because the generators themselves are easier to ship), would this be akin to a meteor strike?
Someone stands on a street corner in an impenetrable shield. They yell advertising / doomsaying / political nonsense at you every time you pass. They do not stop. Is there some way for the authorities to de-activate someone’s shield so they can be arrested?
The government might decide a perfect way of dealing with unwanted stuff (garbage, nuclear waste, chemicals) is to store it inside a large shield. Where it can never hurt anybody ever again. Ever. Until, after many years of sweeping such problems under the rug, the shield fails and we face an enormous problem all at once.
One could create a large shield (or series of shields) underwater. If you are not paid one hundred billion dollars immediately, you’ll turn the shields off. Suddenly, a huge amount of water rushes into an area previous held water-free by the shield(s). With the correct placement (and dis-placement) you could create tsunamis and flood coastal areas.
Presumably, many precautions would be taken so that the shields could not be “hacked” and turned off by terrorists or criminals. But if they default to “on”, how hard would it be to hack them into never turning off at all? How long would the air supply last under the shield?
Does this shield extend into the ground? How does that affect pipes, wires, and other utilities? Could a strategically placed shield completely sever vital lines with the flip of a switch?
If shields around cities / large areas become common, how does this affect the temperature and climate? Are the shields more or less reflective than what we have now? How much heat do they absorb and radiate? How does this affect rainfall and evaporation? Do the large shields mess with wind patterns? Bird migration? Other animal and plant life may be affected as well.
If the shields look like glass, smoky or not, they are clearly distorting light to some degree. If they can be made to focus light, then someone could create a giant lens in the sky. Imagine an evil kid with a magnifying glass frying ants, except replace “kid” with “terrorist” and “ants” with “Manhattan”.
What if some madman put a shield around Pittsburgh and threatened that if he wasn’t paid one hundred billion dollars immediately, he’d let them all out?