• Question: How much energy does the sun produce?

    Asked by Anon to Yasmin, Natasha, Jemma, James, Davide, Craig, Charlie on 25 Jan 2017.
    • Photo: Davide Moia

      Davide Moia answered on 25 Jan 2017:

      The total energy emitted by the sun is a quantity I would have to look up. I can tell you that the amount of power that the earth receives from the sun is in the order of 1000 Watts per square metre. That means that one square metre receive enough energy to power a couple of washing machines. Of course the challenge is being able to collect that energy, but that is what solar cells are for!

    • Photo: Craig Fisher

      Craig Fisher answered on 26 Jan 2017:

      According to a number of physics websites I looked up, the Sun produces about 38,460 septillion watts (3.85×10^26 joules per second). Only about 2 billionths of this reaches Earth. Almost all of its energy is produced within the Sun’s core, where the nuclear reactions take place, which is why its inner temperature is a toasty 15.7 million oC, while the surface is a mere 5,500 oC (or thereabouts).

      Using Einstein’s famous equation E=mc^2, you can show that the Sun consumes around 4.3 million tonnes of matter per second, or the equivalent of 100 Earths (about 0.03% of the Sun’s total mass) over its lifetime so far (approx. 4.6 billion years). Don’t worry, though – there’s still plenty of hydrogen and helium left to power the Sun for at least another 10 billion years, so you can put off that trip to Bermuda for a while longer yet!

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