I'm getting impatient for my flying car. It's been promised to me as early as the '50s.
April 15, 2010 11:36 AM Subscribe
(via Wired about flying cars & Darpa). Explain to me like you would to a twelve year old how far we are with the concept of anti-gravity (Heim theory etc.) Is it theoretically possible? How would it work? When can I order my flying car?
Every time I'm stuck in traffic, I think: how much easier would traffic be if we could just lift cars as little as 3 to 10 meters off the ground. No more crossroads with stupid lights that block you from using the crossroads half the time (or even more).
Then again, this idea of autocopters - basically fitting cars (and their drunk drivers) with big chunks of metal that spin around at a few 1000 RPM is not particularly appealing. Think of the noise, the energy required. Think of the price of driving/flying lessons! So: antigravity. When? How?
Every time I'm stuck in traffic, I think: how much easier would traffic be if we could just lift cars as little as 3 to 10 meters off the ground. No more crossroads with stupid lights that block you from using the crossroads half the time (or even more).
Then again, this idea of autocopters - basically fitting cars (and their drunk drivers) with big chunks of metal that spin around at a few 1000 RPM is not particularly appealing. Think of the noise, the energy required. Think of the price of driving/flying lessons! So: antigravity. When? How?
When you look at all of the other three fundamental forces (let's not unify them just yet), you wonder why gravity matters. The electromagnetic force is roughly 1040 times more powerful than gravity. The strong and weak nuclear forces are less powerful, but they're still fairly amazing. Of course, those two are short-range forces, dropping off relatively quickly. EM drops off like 1/r2, just like gravity. However, with EM, you have positive and negative charges and things tend to mix together, then cancel out as you step back. Not so with gravity. It always attracts. Oh, people postulate some exotic matter with negative mass, not antimatter, but negative mass. Nobody has seen it or has any idea how to make it. Gravity relentlessly attracts, never canceling out, reaching over distances for which the strong nuclear force cannot hope. Despite looking like the weakest contender, it wins, sculpting structure over millions of light years where other forces cannot.
Gravity rules you.
Einstein's big idea for general relativity, from which all related theory descends, is a fundamental unity (the equivalence principle) between gravitation and inertia, between mass in the context of gravitational attraction of an object and mass in the context of being able to alter the relative velocity (or lack thereof) of that same object. Knowing that, any antigravity technology will probably have to deal quite a bit with inertia itself, that resistance to shoving a bowling ball into motion relative to you. One might wonder if an object without gravity would also be an object without inertia at all.
I would not want to be in a vehicle with no inertia.
Of course, one may hope that you could somehow separate the two, keep the inertia, lose the gravity. I think how will tell you when. Given my feelings about How, my When is "never."
posted by adipocere at 12:00 PM on April 15, 2010 [3 favorites]
Gravity rules you.
Einstein's big idea for general relativity, from which all related theory descends, is a fundamental unity (the equivalence principle) between gravitation and inertia, between mass in the context of gravitational attraction of an object and mass in the context of being able to alter the relative velocity (or lack thereof) of that same object. Knowing that, any antigravity technology will probably have to deal quite a bit with inertia itself, that resistance to shoving a bowling ball into motion relative to you. One might wonder if an object without gravity would also be an object without inertia at all.
I would not want to be in a vehicle with no inertia.
Of course, one may hope that you could somehow separate the two, keep the inertia, lose the gravity. I think how will tell you when. Given my feelings about How, my When is "never."
posted by adipocere at 12:00 PM on April 15, 2010 [3 favorites]
That's not very much energy at all - a few mL of gasoline could do it.
The problem is that antigravity, in the form the OP is talking about (not in the form of, say, a chair), is as unlikely to be developed as anything you can imagine. You ask how far we are with the concept? Pretty far. Scientific consensus is that it's not going to happen and that "Heim theory" is wrong or unintelligible.
posted by Mapes at 12:01 PM on April 15, 2010
The problem is that antigravity, in the form the OP is talking about (not in the form of, say, a chair), is as unlikely to be developed as anything you can imagine. You ask how far we are with the concept? Pretty far. Scientific consensus is that it's not going to happen and that "Heim theory" is wrong or unintelligible.
posted by Mapes at 12:01 PM on April 15, 2010
Response by poster: @The World Famous. I would reckon that any flying car would not be piloted by humans but by computers. If we could solve gravity, surely we can take human driving out of the equation. I would be strongly in favour of doing that long before we start antigravity cars...
posted by NekulturnY at 12:09 PM on April 15, 2010
posted by NekulturnY at 12:09 PM on April 15, 2010
I am not a physicist but my tenuous, layman's grasp of QM suggests we're closer to finding the key to mass teleportation than levitation. Which would render moot the whole point of flying cars. Of course, we're pretty far away from that particular breakthrough too.
posted by The Winsome Parker Lewis at 12:13 PM on April 15, 2010
posted by The Winsome Parker Lewis at 12:13 PM on April 15, 2010
Response by poster: Hm, The World Famous, even with computer controlled traffic, I can see huge benefits to flying cars (you're quite the buzzkiller, btw!). Seriously: a road or crossroads, no matter how intelligently designed and managed, can only take so much traffic in a given amount of time and will congest when millions of people leave the office in the evening (cities are expected to grow even more dense in the next century).
With the possibility of stacking traffic - even in neat rows - in 5, 10 or more layers, there would be considerable benefits. On top of that, you could probably give the streets back to pedestrians; and you probably wouldn't need to maintain asphalt roads, which cost millions in repairs (and resources).
posted by NekulturnY at 1:26 PM on April 15, 2010
With the possibility of stacking traffic - even in neat rows - in 5, 10 or more layers, there would be considerable benefits. On top of that, you could probably give the streets back to pedestrians; and you probably wouldn't need to maintain asphalt roads, which cost millions in repairs (and resources).
posted by NekulturnY at 1:26 PM on April 15, 2010
NekulturnY, I've read (unfortunately I don't have a source in front of me at the moment) that traffic jams are actually created much more by variation than by volume. I could easily imagine a computer-controlled system that was observing both the individual car and the entire network and controlling the pacing, spacing and direction of each car such that it could balance out loads and significantly improve even the most snarled traffic.
posted by Slothrop at 1:47 PM on April 15, 2010 [1 favorite]
posted by Slothrop at 1:47 PM on April 15, 2010 [1 favorite]
Although I agree with The World Famous about the impracticality of flying cars as a mainstream transportation system (I think even computer controlled traffic would result in tons of fatalities and property damage when something fails), the sort of levitation technology you're talking about would undoubtedly have tons and tons of extremely useful applications.
Unfortunately, I think we're so far off from having anything like that, we wouldn't even know where to start. Like, as close as a Chimpanzee is to creating a sentient AI. According to our current understanding of physics, there's just no way. It's possible we'll never learn how to create "anti-gravity". It's possible that it just can't be done.
However, I Am Not A Physicist.
posted by Vorteks at 1:12 PM on April 16, 2010
Unfortunately, I think we're so far off from having anything like that, we wouldn't even know where to start. Like, as close as a Chimpanzee is to creating a sentient AI. According to our current understanding of physics, there's just no way. It's possible we'll never learn how to create "anti-gravity". It's possible that it just can't be done.
However, I Am Not A Physicist.
posted by Vorteks at 1:12 PM on April 16, 2010
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posted by dfriedman at 11:41 AM on April 15, 2010