Cold

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Cold winter weather

Cold is a relative term used in comparison with the adjective warm (opposite of cold). Because it is relative, there is no range in coldness. The temperatures in the winter season are often categorized as being cold. Cold is the opposite of hot.

The coldest possible temperature is −273.15 °C, which can be expressed as about -459.67 °F on the Fahrenheit scale. This is called absolute zero. Absolute zero is also 0 K on the Kelvin scale and 0 °R on the Rankine scale

Cooling[change | edit source]

Cooling is when an object gets cold, or lowers in temperature. This can happen by taking away heat, or by putting something in a place with a lower temperature. Fluids used to cool objects are called coolants.

Air cooling making the temperature of an object lower using air. This will only work if the air is at a lower temperature than the object. The process will work better if there is more surface area on the object or if the item's mass can be made smaller.

Other ways to cool objects include using ice, dry ice, or liquid nitrogen. This works by convection; the heat is taken from the relatively warm object to the relatively cold coolant.

Cold locations and objects[change | edit source]

  • The Boomerang Nebula is the coldest known place in the universe. Scientists believe the temperature is 1 K (kelvin) (−272.15 °C/−457.87 °F).[1]
  • Herschel Space Observatory equipment is kept at temperatures below 2 K, using a large helium tank for cooling.[2]
  • Neptune's moon Triton has a surface temperature of −235 °C (−390 °F).
  • Uranus has an atmospheric temperature of −215 °C (−355 °F).[3]
  • Saturn has a temperature of −175 °C (−285 °F) at cloud tops.[4]
  • Mercury, even though it is close to the Sun, is actually cold during the night. It has a temperature of about −170 °C (−275 °F). Mercury is cold at night because it has no atmosphere to trap in heat from the Sun.[5]
  • Jupiter has a temperature of −145 °C (−230 °F) at the cloud tops.[6]
  • Mars has a temperature of about −125 °C (−195 °F).[7]
  • The coldest continent on Earth is Antarctica.[8] The coldest place on Earth is the Antarctic Plateau,[9] an area of Antarctica around the South Pole that has an altitude of around 3000 meters. The lowest measured temperature on Earth, −89.2 °C (−128.6 °F), was recorded at Vostok Station on 21 July 1983.[10]

References[change | edit source]