How can we be sure that temperature has a limit on the negative end

well as temperature decreases particles move slower. so there has to be an end when the particles completely stop. that is 0 kelvin. you cant go negative movement because that would still be movement so there is a defined stop point called absolute zero

Just trying to be logical, but on the Kelvin scale, also called Absolute, there is no negative end. When the temperature hit's zero, the body has no more heat left to radiate, By inference, those scales that do have negative temperatures, have a negative number that matches 0 Kelvin. They can not go beyond this number because there is no heat left to radiate.

To remove heat and consequently lower the temperature, we must have a sink of lower heat content to move that heat into. At absolute zero, there is no sink, no lower heat content by definition.

So as we approach that august limit, we eventually run into the heat sink barrier where that last calorie of heat cannot be removed because we do not have the technology to do it. So even though 0 deg K is the theoretical limit, the practical limit is some iota above that.

And 0 deg K is the theoretical limit because there is no such thing as negative heat. We can't lower something that is no longer there, which is the heat at zero degrees...it's no longer there...theoretically. Practically of course, as we just revealed, there will always be some iota of heat remaining.

Because the removal of heat energy down to -273.15°C (Zero Kelvin (K) Absolute) has been attempted by Scientists with no luck.

In Fahrenheit, absolute zero is -459.67°F (Zero Rankine (R) Absolute).
A very close temperature has been achieved but not as low as absolute zero.

All motion of atoms stops at a certain temperature. Since motion of atoms and heat are the same, that must be the lower limit, absolute zero (0*K or -273*C)

How can we be sure that temperature doesnt have a limit on the positive side?