Absolute zero | Definition & Facts (2024)

temperature

verifiedCite

While every effort has been made to follow citation style rules, there may be some discrepancies.Please refer to the appropriate style manual or other sources if you have any questions.

Select Citation Style

Feedback

Thank you for your feedback

Recent News

July 4, 2024, 7:47 AM ET (Space.com)

Scientists tap into 2 new quantum methods to catch dark matter suspects

absolute zero, temperature at which a thermodynamic system has the lowest energy. It corresponds to −273.15 °C on the Celsius temperature scale and to −459.67 °F on the Fahrenheit temperature scale.

The notion that there is an ultimately lowest temperature was suggested by the behaviour of gases at low pressures: it was noted that gases seem to contract indefinitely as temperature decreases. It appeared that an “ideal gas” at constant pressure would reach zero volume at what is now called the absolute zero of temperature. Any real gas actually condenses to a liquid or a solid at some temperature higher than absolute zero. Therefore, the ideal gas law is only an approximation to real gas behaviour. As such, however, it is extremely useful.

Britannica QuizApril Showers to March’s Lions and Lambs

The concept of absolute zero as a limiting temperature has many thermodynamic consequences. For example, all molecular motion does not cease at absolute zero (molecules vibrate with what is called zero-point energy), but no energy from molecular motion (that is, heat energy) is available for transfer to other systems, and it is therefore correct to say that the energy at absolute zero is minimal.

Any temperature scale having absolute zero for its zero point is termed an absolute temperature scale or a thermodynamic scale. In the International System of Units, the Kelvin (K) scale is the standard for all scientific temperature measurements. Its fundamental unit, the kelvin, is identical in size to the Celsius degree and is defined as 1/273.16 of the “triple point” of pure water (0.01 °C [32.02 °F])—i.e., the temperature at which the liquid, solid, and gaseous forms of the substance can be maintained simultaneously. The interval between this triple point and absolute zero comprises 273.16 kelvins. The lowest temperature achieved in experiments has been 50 pico*kelvin (pK; 1 pK = 10⁻¹² K).

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Adam Augustyn.

FAQs

Absolute zero | Definition & Facts? ›

Absolute zero is the lowest temperature possible. At a temperature of absolute zero there is no motion and no heat. Absolute zero occurs at a temperature of 0 kelvin, or -273.15 degrees Celsius, or at -460 degrees Fahrenheit.

Read On ›

What are some interesting facts about absolute zero? ›

It corresponds to −273.15 °C on the Celsius temperature scale and to −459.67 °F on the Fahrenheit temperature scale. The notion that there is an ultimately lowest temperature was suggested by the behaviour of gases at low pressures: it was noted that gases seem to contract indefinitely as temperature decreases.

Discover More ›

What is the best definition of absolute zero? ›

Absolute zero is the lowest possible temperature where heat energy is absent in a substance. Absolute zero is also known as zero kelvin temperature since it measures zero on the Kelvin scale. Minimal vibrational motion is displayed at this temperature by fundamental particles of nature.

What 2 things are true about absolute zero? ›

There is no motion of the particle of the substance at absolute zero, therefore each particle is at rest. The heat of the substance at absolute zero is zero.

What is absolute zero for kids? ›

In physics, absolute zero is the coldest temperature that is theoretically possible. It is attained when molecular movement virtually ceases and the lowest level of energy is reached. Absolute zero measures –273.15° on the Celsius scale and –459.67° on the Fahrenheit scale.

See Details ›

What would absolute zero do to a human? ›

At this extreme cold, the amount of energy available to the body for its functions decreases and diminishes entirely. Heat energy dissipates, leaving the body unable to maintain its natural processes. The behavior of electrons and the conduction of energy would drastically change from the usual conditions.

Learn More Now ›

Can anything exist at absolute zero? ›

Absolute zero is not possible, as the third law of thermodynamics states that a system cannot be cooled to absolute zero.

Show Me More ›

What cool things happen at absolute zero? ›

At very low temperatures in the vicinity of absolute zero, matter exhibits many unusual properties, including superconductivity, superfluidity, and Bose–Einstein condensation. To study such phenomena, scientists have worked to obtain even lower temperatures.

Does time stop at absolute zero? ›

But even if you take the conventional view of the flow of time, motion does not stop at absolute zero. This is because quantum systems exhibit zero point energy, so their energy remains non-zero even when the temperature is absolute zero.

Know More ›

Is there anything colder than absolute zero? ›

Is your system really colder than zero Kelvin? No! Nothing can be colder than absolute zero (0K)! Negative absolute temperatures (or negative Kelvin temperatures) are hotter than all positive temperatures - even hotter than infinite temperature.

What happens if absolute zero is reached? ›

When it comes to how cold things can get there is a fundamental limit. In 1848, Lord Kelvin introduced the idea of absolute zero. This is the point at which the atoms in an object stop moving entirely and so can't get any colder.