Final answer:
The coldest part of the atmosphere is the tropopause, and the coldest recorded temperature on Earth's surface was at Vostok, Antarctica. Colder temperatures have been achieved in labs, notably at MIT and Helsinki University of Technology.
Step-by-step explanation:
The coldest part of Earth's atmosphere is the tropopause, which is the transition layer between the troposphere and the stratosphere. In this region, temperatures can plummet significantly as altitude increases, eventually reaching their lowest point just before the stratosphere begins where the temperature starts to increase due to the absorption of UV radiation by ozone. Renowned atmospheric and climate scientist, Susan Solomon, has made significant contributions to the understanding of atmospheric chemistry, including issues relating to the coldest temperatures in the atmosphere.
Furthermore, the coldest temperature ever recorded on Earth's surface was in Vostok, Antarctica, reaching 183 K (-89°C). Interestingly, even colder temperatures have been achieved in laboratory experiments such as those conducted at the Massachusetts Institute of Technology (MIT) in the USA, and the Helsinki University of Technology in Finland.