Physicists have 'solved' mystery of levitation
By Roger Highfield, Science EditorLast Updated: 1:41am BST 08/08/2007
Levitation has been elevated from being pure science fiction to science fact, according to a study reported today by physicists.
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In theory the discovery could be used to levitate a person |
In earlier work the same team of theoretical physicists showed that invisibility cloaks are feasible.
Now, in another report that sounds like it comes out of the pages of a Harry Potter book, the University of St Andrews team has created an 'incredible levitation effects’ by engineering the force of nature which normally causes objects to stick together.
Professor Ulf Leonhardt and Dr Thomas Philbin, from the University of St Andrews in Scotland, have worked out a way of reversing this pheneomenon, known as the Casimir force, so that it repels instead of attracts.
Their discovery could ultimately lead to frictionless micro-machines with moving parts that levitate But they say that, in principle at least, the same effect could be used to levitate bigger objects too, even a person.
The Casimir force is a consequence of quantum mechanics, the theory that describes the world of atoms and subatomic particles that is not only the most successful theory of physics but also the most baffling.
The force is due to neither electrical charge or gravity, for example, but the fluctuations in all-pervasive energy fields in the intervening empty space between the objects and is one reason atoms stick together, also explaining a “dry glue” effect that enables a gecko to walk across a ceiling.
Now, using a special lens of a kind that has already been built, Prof Ulf Leonhardt and Dr Thomas Philbin report in the New Journal of Physics they can engineer the Casimir force to repel, rather than attact.
Because the Casimir force causes problems for nanotechnologists, who are trying to build electrical circuits and tiny mechanical devices on silicon chips, among other things, the team believes the feat could initially be used to stop tiny objects from sticking to each other.
Prof Leonhardt explained, “The Casimir force is the ultimate cause of friction in the nano-world, in particular in some microelectromechanical systems.
Such systems already play an important role - for example tiny mechanical devices which triggers a car airbag to inflate or those which power tiny 'lab on chip’ devices used for drugs testing or chemical analysis.
Micro or nano machines could run smoother and with less or no friction at all if one can manipulate the force.” Though it is possible to levitate objects as big as humans, scientists are a long way off developing the technology for such feats, said Dr Philbin.
The practicalities of designing the lens to do this are daunting but not impossible and levitation “could happen over quite a distance”.
Prof Leonhardt leads one of four teams - three of them in Britain - to have put forward a theory in a peer-reviewed journal to achieve invisibility by making light waves flow around an object - just as a river flows undisturbed around a smooth rock.
Re:"At several points in his article, he argues that cosmologists are doing work that has been hijacked by creationists."
-Religion was the first cosmologist. The stars were believed to be gods, heavens, etc. long before we were able to look with a telescope, or track the motions. We started with a theory based on what we could observe, and the modified it as new observation were able to be made. The chariot of fire is a perfect example. Believed to be pulled across the sky by a god, now believed to be a burning ball of gas. We observed that it looked like it was on fire, but our explanation of the fire was incorrect. Cosmologic beliefs evolved as technology evolved. Religion has clung to it's belief and changed it to fit in with new observation the same as science has.
Re: "We've got the scientific structure and framework incorrect. We need a theory that is internally consistent. We can't do this without creating a biological understanding of space and time. This will require restructuring science so that biology is above physics."
-Biology=study of life
What defines life? While there are still problems with scientifically defining life, we of come to several criteria that define life. Time and space do not meet any of the criteria for being alive. So how can we biologically define them? Both are perceptions, perceived by humans and some animals. If there is no one to perceive time, does it exist? How can we apply biological theory to a perception?
I don't think that physics is above biology now. Both are schools of thought based on observation of natural events. Both seek to explain the natural phenomena that occurs (based on our perception of it). Physics applies to biology, and vice versa.
Re:"WN: In your article, you make the assertion that time and space do not exist. What do you mean by that?
Lanza: There is something very unusual about them. We can't put them in a marmalade jar and take them back to the lab for analysis. Space and time are forms of animal sense perception. Space and time are not objects or things -- they are forms of animal sense perception."
-My point exactly. If they don't exist, why would we apply the laws of observation based on things that do exist? Every law that we accept in biology came from the observations of existing things. We wouldn't apply the data from sand to make observations about rocks. They are different. The structure of the world and the structure of thought are different, too. You simply cannot expect to use laws based on observable world phenomena for anything created by thought.
Re:"Scientists continue to dismiss the observer as an inconvenience to their theories. Real experiments show that the properties of matter itself are observer-determined. A particle can go through one hole if you look at it, but if you don't look at it, it can actually go through more than one hole at the same time. Science has no explanation for how the world can be like that."
-The term "Science" is far to broad for such a statement. Hundred of experiments are done and results published in reputable journals regarding just such research. "Science" has not found a way to put them into laws, yet. There are thousands of theories out there, but we are still trying to figure out how to prove and disprove them. All of out scientific laws were at the beginning experimental stage at some point.
We should not try to fit things into labels before we understand them. We should try to understand them, so that we may design our models to fit what is truly happening. We should not create a system, and then try to fit the world into it."