Thursday, September 22, 2011

Ask Dr MamaR: What is the sun made of?

Today's question: What is the sun made of?
(or "Out of what is the sun made?", but does your kid use proper grammar like that? Mine doesn't.)

Short answer: listen to This Song and This Song, by They Might Be Giants. Those guys have it pretty much under control. But if you are still curious, keep reading...

Grown-up/High School Answer
Technically, the sun is:
71% hydrogen
27% helium
1% oxygen
1% other elements (iron, nickel, silicon, sulfur, magnesium, carbon, neon, calcium and chromium)

The sun is composed of several layers, and if you were to dig in from the surface you would find each layer to be hotter and at a higher pressure than the one before. Of course, you couldn't do this, because it's hot. Really hot. Around 15 million degrees, give or take a few. The core of the sun is so hot and at such a high pressure that it acts as a nuclear fusion reactor, squishing hydrogen atoms into helium atoms. This nuclear reaction creates the light and heat we get from the sun.

Thanks, NASA

In the sun, most of the elements listed above are actually in the form of plasma. Plasma is a fourth state of matter (the other three being solid, liquid and gas). It's a lot like a gas, except it is at such a high energy that most of the molecules have broken apart into positively and negatively charged pieces. The fact that the molecules are charged makes plasmas interesting because they respond to magnets or electric fields. Or in the case of our sun, interact with planets' magnetic fields.

Thanks again, NASA

Grade School Answer:
The sun is mostly made of two gasses: Hydrogen and Helium. These gasses are really really hot and at a really really high pressure, which makes them act like a special kind of gas called a plasma (not the same kind of plasma as in your blood!). Also, at really really high temperature and pressure, two Helium atoms can be combined to make a Hydrogen atom. This is called a nuclear fusion reaction, and it produces a LOT of energy. This reaction is happening in the core of the sun, which is why the sun gives off so much energy (in the form of light and heat)!

Pre-school Answer:
The sun is made of plasma that is really really really hot. Plasma is kind of like air, but hotter and thicker and in the sun it produces lots of light and heat.

Good luck! And if your kids have more questions, please email them to DoctorMamaR (at) User tip: you are allowed to ask your own questions and claim they are from your kids. :)

Dr. Mama R has a PhD in Materials Science and Engineering, which she puts to good use teaching undergraduates and her two little kids. One of these groups is REALLY interested in boogers, both wonder why the sky is blue.


  1. Ah! I'm so glad to have found your blog and I like it and hope that you continue posting.Great answer!Now I'm easily answered and understand clearly about sun my kid.

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