Simple answer: It is not possible. That's one way to formulate the second law of thermodynamics.

But it's often that people just associate temperature with the kinetic energy of the particels, which comes from the kinetic gas theory. That's a too specific concept: In statistical mechanics temperature is more general defined as 1/T=dS/dE, which reflects the "unordered" characteristic of thermal energy. You can easy see that by looking at a snowball, it doesn't melt because you throw it (neglecting air resistance), although you cerainly raise the kinetic energy of each atom in it.

I believe that the government tried to achieve absolute zero before and succeeded for a fraction of a second.   I have no idea how they did it, but I'm sure it used a lot of energy to get anywhere near that cold.

It's not possible. Absolute zero is only an approximation or limit being placed at how cold we can actually get something to be and at where matter's vibrations appear to stop, even though they don't.  Absolute Zero itself isn't even absolute, it has been slowly becoming a smaller and smaller number since its inception.  Basically it is 'x' over infinite as 'x' approaches 0, since zero cannot be reached absolute zero is just the value calculable closest to 0.

absolute zero is NOT possible because then all matter ceases to move. we only know this because of experimental tests.

FYI: the temperature of the universe (measured in deep space where there is one atom per cubic kilometer) is around -270 Celsius and dropping (with the start point of the Big Bang). It is believed that if our universe is an open universe, the energy will continue to expand the universe until temps reach absolute zero, which is when the universe just dies out into a frozen, unmoving place.

It is physically not possible.  If a particle were frozen completely, this would violate the Heisenberg uncertainty principle.  Particles of matter do not follow the same laws as the big stuff we normally deal with.  Particles are only "likely to be" here or there, and "likely to be" moving at this or that velocity.  Even if you presumably cooled something to absolute zero, it's only a probability.  

The more accurately you measure momentum of a particle, the less accurately you can measure its location in space.  So if you "know" that it is at absolute zero (zero movement), then it could be located anywhere, maybe in another galaxy.

Also, movement is relative.  If a particle were at absolute zero compared to some other particle next to it (or likely to be next to it), it would still be moving in relation to something.  The rest of the universe is still in motion..

You are right in questioning how it would be possible.  It's not.  There might be instances of time when a couple of particles are 100% stationary relative to each other, but they wouldn't stay that way for long, there would be no practical purpose, and they could never be measured because simply measuring them would jolt the particles out of sync again.

The hypothetical absolute zero arises directly out of the laws of thermodynamics. So your question is poorly founded.

It is possible to get substances cold enough that the atoms in them no longer vibrate. In most conceptual respects this means they reach absolute zero. It is also possible to coool them even further by condensing the quantume states of their nuclei.

But it is not possible to overcome the zero point motion of particles in the nuclei. However, at this point you are beyond the ideas of thermodynamics.

The Laws of Thermodynamics does not preclude the possibility of reaching absolute ZERO, even though it is practically extremely difficult to reach.

However, it is physically IMPOSSIBLE to reach absolute ZERO for another reason: Quantum Jitters.

At the subatomic level, no particle will stay absolutely motionless. At very short time and spatial scales, there are huge fluctuations consisting of particle-antiparticle pairs with arbitrary amounts of energy. Even space and time itself are fluctuating. This means you can NEVER achieve absolute zero.

This quantum jitter is due to Heisenberg's Uncertainty Principle, but even beyond that there is what is called "vaccum energy", meaning that even in empty space devoid of any matter or energy, there is still a minimal level of energy contained in space itself.

It's not (even is free space).  You said it yourself, hypothetical.  It's purely theoretical.  Good on you for realizing it.

We can never prove it, because our observations would cause movement => heat.

Absolute zero can only occur theoretically, based on our current limitations. Only when a system can create no more entropy could this even be possible. Witnessing a specimen is not yet possible, as the ability to view it would increase the temperature

The lowest possible temperature; according to the kinetic theory of gases, this is the temperature at which all motion of atoms and molecules ceases. This temperature is equivalent to ?273.16 ?C, and defines the zero of the kelvin, or absolute, temperature scale.

Heat is quantifiable, it can be measured... if you suck all the heat out of a bunch of Helium it liquefies at around 4 degrees Kelvin. If you could extract ALL the kinetic energy from each atom of Helium then it would freeze solid and you would be at 'absolute zero' Nobody has figured out a way to do that yet, and they probably never will. Some small amount of kinetic energy is sort of built in to all atoms, because of the nature of their electrons.