What is the lowest temperature that anything can be?

Answer 1

When calculating the temperature in space, it is important to understand that most estimates must take into account the varied makeup of space. Outer space is the portion of the universe which is almost entirely empty. Unlike the small pockets of our universe which are inhabited by stars, planets, and other large sections of matter, outer space contains very, very little. Nonetheless, it is not entirely empty, and this is important to understand when considering the temperature in space.

The short answer is that the temperature in space is approximately 2.725 Kelvin. That means the universe is generally just shy of three degrees above absolute zero - the temperature at which molecules themselves stop moving. That's almost -270 degrees Celsius, or -455 Fahrenheit.

In one sense, we can talk about the temperature in space as being 2.725 K. This shifts a bit from place to place, but not by much more than a thousandth of a degree. For all intents and purposes, this is the generally accepted temperature in space.

To understand it further, we can look at what a temperature actually is, and what space actually is. When we're measuring the temperature of something, what we're really talking about is the energy of the molecules in it. It has to do with the density of the molecules, which in turn helps determine how often they run into one another. If they don't run into one another, they never really lose their initial energy.

Space is very, very empty. There aren't many molecules out there, which means none of the molecules have much of a chance to run into one another. What does this have to do with the temperature in space? If we were to take a random molecule in space, say one that is part of the solar winds, and estimate its temperature, it would probably be around a million or more degrees Kelvin. That's because this molecule hasn't been bumping into things to get to the temperature it naturally wants to be at - what is called its equilibrium.

Answer 2

0 Kelvin

-273.15 Celsius

-459.67 Fahrenheit

Answer 3

It has to be at least -128.6 oF, and at most 136 oF.

Answer 4

Absolute zero is as cold as cold gets. :]