The Burning Sun

For me, the internet is about the instant access to information through Google or Wikipedia. I love having a constant stream of new information to feed my addiction to knowledge.

For example, the other day I was thinking about the core of the Sun and how much energy it takes to balance the extraordinary mass of the Sun.

According to Wikipedia, the core of the Sun converts about 3.4×1038 free protons (hydrogen nuclei) into helium nuclei every second.  I looked up the mass of the proton (1.672×10-27 kg), multiplied the two numbers to get 568,691,140 metric tons. Each second, 568 million tons of free protons are converted to helium (two protons). But how big is that really? The article did not give the context. It would require more digging.

I thought perhaps I could compare that mass with, say, a mountain. Searching in Google, I found that the estimated mass of Mount Everest from the base camp (17,500 feet) to the peak (29,035 feet) is 357 trillion pounds or 161 billion tons. So the Sun converts about 0.35% of the mass of Mount Everest from hydrogen to helium.

In the thermonuclear reaction, a fraction of that mass is lost. About 4.26 million metric tons of mass is lost each second, converted to energy following the famous mass-energy equivalence equation (E=mc2). Which is less than 1% of the amount converted from hydrogen to helium, but the speed of light (squared) is so large the actual energy output is staggering – 383 yottawatts (3.83 × 1026W).

But just how large is that lost mass? What is 4.26 million metric tons equivalent to in a form I can understand? Back to Google, and I find that the mass of Hoover Dam is 6.6 million US tons or 5.99 million metric tons of concrete.

So, now I can compare the two. Each second, the Sun converts about 71% of the mass of the Hoover Dam into all of the energy that holds up the outer layers of the Sun, and produces all of the heat and light (which are really the same thing – photons) that bathes our planet. That energy produces enough photons that 149.6 million kilometers away over half of our planet is lit so that I can read, take pictures and get a sunburn.

It’s amazing that all of that power comes from something as small. The Hoover Dam and Mount Everest are infinitesimally small compared with the total mass of the Sun.

But it’s more than enough to satisfy my thirst for knowledge for one evening.

2 Replies to “The Burning Sun”

  1. Hi Richard

    Thank you so much for your thoughtful post. I know this was written back in 2009 but I just came across it. I am in LA and had the sun in my eyes and was wondering how much mass was being transformed into energy each second. Like you, I love being able to get this information almost instantly but one does not always come across a kindred soul that makes it so easy to comprehend. Thanks again.


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