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Written by Matthew Dunn
Illustrated by Alex Hallatt

From absolute zero to the surface of the Sun, there’s a whole range of temperatures in our Universe. Let’s learn more!

−273.15 °C
Absolute zero

Absolute zero is, unsurprisingly, the lowest temperature possible. When things get colder, their particles slow down. At −273.15 °C, they are motionless and entropy is zero. We can’t cool things down to absolute zero, but Finnish scientists have got very close − even as close as 0.000 000 001 °C above it.

−196 °C
Liquid nitrogen boils

While we’re most familiar with nitrogen as a gas in the air around us, when it’s cooled down below −196 °C, it turns into a liquid. Liquid nitrogen isn’t just super cool – it’s also super useful for science. It can be used to store biological samples, freeze off moles that might be cancerous, and cool down superconductors!

−93.2 °C
Coldest temperature on Earth

The coldest temperature ever recorded on Earth was on the 10 August 2010, in – you guessed it – Antarctica! The recording was made using satellites that detect heat radiating from the surface of the planet.

−13 °C
Ideal ice cream serving temperature

According to the International Ice Cream Association – who you’d hope would know a thing or two about ice cream – somewhere between −12 and −14 °C is the perfect temperature for this icy treat. But, when you’re not busy licking it, make sure it’s in a freezer set between −18 and −20 °C.

0 °C
Water freezes

While pressure is also an important factor for changes of state, 0 °C is when ice forms at standard atmospheric pressure. This is no coincidence, because the Celsius scale was originally created by dividing the difference between water’s boiling point (100 °C) and the melting point of ice into one hundred degrees.

37 °C
Body temperature

Although there is some variation even among healthy people, most of us have an internal temperature close to 37 °C. A change of even one or two degrees to this internal temperature means trouble for our health, with fevers being a common example. And, if body temperature’s not a gruesome enough name for your liking, don’t worry – it used to be called blood heat.

56.7 °C
Hottest recorded day on Earth

Death Valley in California lays claim to the title of the hottest place on Earth after the temperature hit 56.7 °C in July 1913. The hottest recorded temperature in Australia is a full six degrees cooler than that, with 50.7 °C recorded at Oodnadatta in South Australia in 1960.

1000 °C
Lava

Okay, so not all lava is exactly 1000 °C. The temperature of lava depends largely on what type of rock it’s made out of. While molten rhyolite can be as cool as 650 °C, basalt-based lava can be more than 500 °C higher than that. But, no matter what it’s made of, it’s not something you’d want to get too close to!

30 000 °C
Lightning bolt

Lightning strikes release a huge amount of energy, heating the surrounding air so fast that the air expands faster than the speed of sound. The resulting shockwave is what we hear as thunder.

2 000 000 °C
The Sun’s corona

The temperature of the Sun varies a lot, depending on where it’s measured. At its core, fusion reactions heat it to a whopping 15 000 000 °C, whereas the surface is a mere 5500 °C. Scientists still don’t completely understand why the plasma – or corona – that surrounds the Sun is so much hotter than the surface.

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