Advent calendar / Miscellaneous

Door 22: Alan Partridge in a Pear Tree

twenty two

5 smoke rings,

4 fossil turds,

3 Scottish glens,

2 rocks from above…..

Alan Partridge in a pear tree!

Right. Alan Partridge complains that his microwaved apple turnover is HOTTER THAN THE SUN. Being a dimwitted fellow he does not realise HOW WRONG HE IS. Allow us to explain…

One of these things is a very hot apple turnover.

One of these things is a very hot apple turnover.

The sun is a huge sphere of glowing gases that produces energy and light and its temperature varies enormously. At its core (which constitutes 25% of its radius) it reaches more than 15 million degrees C, as hydrogen atoms get compressed and fuse together forming Helium.

The next layer, the convective zone, can reach a cooler but still devastatingly hot 2 million degrees C. The next zone is the photosphere which drops to around 5500 degrees C – this is the bit where the sun’s radiation is detected as sunlight.

This is followed by the chromosphere which at 4320 degrees C, is decidedly chilly by comparison! Here the light is weaker and can’t usually be seen against the photosphere. Temperatures then rise out to the Corona which can only be seen during an eclipse, and can get as hot as 2 million degrees C. Chemically it is composed primarily of hydrogen and helium, which account collectively for 98.7% of its mass. Heavier elements include oxygen (1%), carbon (0.3%), neon (0.2%) and iron (0.2%).

sun temperature

So, what would happen if we tried to heat an apple turnover up to the temperature of the sun?

Carbohydrates, such as Sucrose and Glucose, comprise around 80% of all food intake by humans and are made up of carbon, hydrogen and oxygen in a 1:2:1 ratio. For simplicity, we’ll assume that the apple pie is mostly carbohydrate molecules, and take sucrose as an example.

Burnt sugar. Nb: not as hot as the sun.

Burnt sugar. Nb: not as hot as the sun.

Sucrose does not melt at high temperatures. Instead, it decomposes at 186 degrees C to form caramel, and like other carbohydrates it combusts to form carbon dioxide and water.

Heating to the level seen even in the outer layers of the sun’s structure would involve a full break down – not just from solid to liquid and then gas, but also the breaking of bonds within molecules (such as CO2 and H2O) The apple turnover would exist as elemental gas which would not constitute a tasty (albeit overly hot) snack. This is evidenced by the almost the total absence of molecules in the sun, it being restricted to elemental atoms in the form of gas or at even higher temperatures,  plasma.

So, there you have it, Alan. Check your facts next time.

3 thoughts on “Door 22: Alan Partridge in a Pear Tree

  1. Pingback: Door 24: A christmas letter from the geoadvent blog team | Geological Society of London blog

  2. Pingback: Door 24: Christmas greetings from the geoadvent blog team! | Geological Society of London blog

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