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Physics/Nano sized cpu or gps.

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QUESTION: Dear expert.
I HAVE ONE QUESTION.
.
My assumption start from the article reading for nano tech.
Now our tech could control the materials with the size of nano.

My assumtion is below.
1. There is 20nano sized semiconductors.
- that means scientist could control the materials with such little size.
But when we see the smallest chip or cpu or gps chip, these are all 2mmx2mm.

2. Does it means  there is some tech limitation for developing such nano size gps chip or module. Eventhough we have nano tech ( regardless of nano tech)
3. So I want to know what is the limitation for tech eventhough todays tech have the tech for contoling the materilas with the size of nano.

In my point of view
If we have the tech of nano, we could make cpu as a nano size (eye cannot see) or nano gps (eye also cannot see)...
What is the main reason.
Because I am not the scientists, pls. Solve my query.
Thank you

ANSWER: Transistors are made even smaller...but that's kinda beside the point here.  A single transistor doesn't make a chip.  A chip is a complex circuit made of thousands or millions of such transistors.  Still way smaller than 2mmx2mm?  Yes.  But these things need power, capacitors for memory, clock inputs, and a substrate to handle them on during manufacture.  Can a chip be made that's very, very small?  Yes.  Is that useful for GPS?  Not really, the thing about GPS is that it has to have an antenna to receive the radio signals from satellites no matter how small you make the chip.  That is pretty fundamental, you can't just eliminate the antenna and have the GPS actually work.  There are all the other practical things, again, like power/timing/data necessary to turn timed radio signals into actual coordinates.  Devices containing microchips are like that, especially something as complex as a GPS receiver...there really are some fundamental limitations on the size you can make it.  Those limits are pushed about as far as they can be already in current devices.  Thousands of very smart people work for a wide variety of companies, all striving (and motivated by the profit potential) to make the very smallest/lightest GPS system.  They've cut all the corners they can, pretty much, but still there are clever advances that cause the size to shrink down to where the fundamental limit (the antenna) is really the limiting factor.  That antenna has to be a few centimeters long just to receive the radio signals.  Smaller than that and the voltage caused by the radio signal would be unreadable.

---------- FOLLOW-UP ----------

QUESTION: Dear expert.
Thank you very much.
I almost understand what I imagine is not impossible.
May I ask last query.
my imagination start? is it possible to make gps tracker with size of 2cm hair (diameter is 0.05mm)
I know there are alot of restrcitons....
1. battery
2, chip size
3. circuit
4. antenna
5. other parts
But in my thought
1. battery   --> with the help of thermo tech... battery could be supply continuous by body temperature (hair sized thermo materials)
2, chip size --> with the help of nano tech. there is alot of tech to reduce the thickness of semiconducts and nano transistor and nano diode
3. circuit --> with the help of nano tech... there is a tech to print very nano sized copper on FPCB.. FPCB could be slimmed by nano tech.
4. antenna --> it is my concern.. 2cmm is enough to recive the signals from satellite and thick is very small...but I think it is enough.
5. other parts  --> could be made by nano or more small size..

but What I concern is
eventhough we could make chip or module small.. it need power to receive and send the signals...
and the circuilt is very small, there are limited power capacity to support to make or receving the right signals from satellite...
So, what I want to know is
is it possible to supply enough power for chip or antenna to receive and send the satellite signals...
if circuit become smaller... is it possible (because it need little current. because chip is very small..
Thank you very muchl.

Answer
GPS doesn't need much power to receive signals, it just depends on what you want to send them to.  At short range, I'm pretty sure you're in the realm of plausible physics.  Sending to a satellite instead of a local receiver, however, is irrelevant...if you want something located by its SENT signal rather than its received signal, then triangulation from receivers can be achieved at very tiny sizes, indeed.  Just needs a tiny amount of power to build up and discharge a burst radio chirp, no problem with that, then external receivers can just triangulate the location of the transmission.  Much smaller.

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Dr. Stephen O. Nelson

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I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

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I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

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Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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