Yeah, but there's no point in knowing that it can get colder when our cells can't tell the difference between ~250 Kelvin and 0 Kelvin because they die up on us.
Not actually correct I'm afraid. You see "temperature" refers to the energy of the particles. A positive temperature (i.e. Every temperature recorded previously) means most particles have low energy and some have high. As you increase the temperature (becomes more positive), more particles will have higher energy, until infinite temperature where there will be an even distribution. "negative" absolute temperature is beyond that so to speak, at which points most particles have the higher energy. As I mentioned earlier "negative" absolute temperatures are hotter than an infinite positive. It's called negative because it is an inversion of the energy distribution of positive temperatures.
Relative to humans technology. Example: You are a scientist whose only method to lower the temperature is a freezer because technology wasn't evolved enough to further lower the temperature. You think it can't get colder than what your freezer provides, so you define the lowest temperature of your freezer as absolute zero.
Again, that is not what has happened here. An absolute negative temperature is not just "a lower value for absolute zero than previously thought". Absolute zero has been calculated, not measured (as far as I know), therefore it's not a case of being limited by our technology; it is indeed absolute. If it were wrong, every other temperature ever recorded in Kelvin would be wrong as well.
The common cold is actually not a response to cold temperatures/weather, but in fact is caused by a virus which spreads from person to person. The virus is constantly mutating, hence our immune systems can't deal with new strains, so we keep catching a cold again and again (although not the same strain, as we will usually have become immune to that one).
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Psionic Roshambo:
