What you learned in school
Physics textbooks taught that absolute zero (-273.15°C or 0 Kelvin) was a theoretical limit that could never actually be reached in practice. Students learned that the third law of thermodynamics made it fundamentally impossible to cool any system to absolute zero temperature. This was presented as an unbreakable physical law, with textbooks emphasizing that while scientists could approach absolute zero, they could never actually achieve it due to quantum mechanical limitations.
What we know now
Physics classes taught that absolute zero (-273.15°C or 0 Kelvin) was the theoretical lowest possible temperature that could never actually be achieved. Students learned about the third law of thermodynamics and the impossibility of reaching this limit. Scientists have created temperatures below absolute zero in laboratory conditions using quantum mechanical systems. These "negative temperature" systems are actually hotter than any positive temperature and represent exotic quantum states. While still extremely difficult to achieve, absolute zero is no longer considered absolutely impossible.