• Question: How bright is the sun?

    Asked by Big sissy to Dervil, Moises, Pramod, Saoirse, Stephen on 4 Nov 2016. This question was also asked by 445ghtg46.
    • Photo: Moises Jezzini

      Moises Jezzini answered on 4 Nov 2016:


      From my answer to “how many light bulbs would you need to be as bright as the sun?”

      The sun produce 3.8 × 10^26 watts. That is 3800000000000000000000000000 watts if you don’t like scientific notation (reference: http://helios.gsfc.nasa.gov/qa_sun.html#power).

      Let’s use 100 Watts light bulbs. We need 3.8 × 10^24 light bulbs. Assume that each bulb weighs 150 grams (around 5 oz). So the 3.8 × 10^24 light bulbs will weight 5.7×10^23 kg. That means that all our light bulbs will weight around 10 times the weight of our planet earth!

      I would not like to pay that electricity bill.

      Expanding a little bit more. Check the next question from from here http://what-if.xkcd.com/141/

      “What if all of the sun’s output of visible light were bundled up into a laser-like beam that had a diameter of around 1m once it reaches Earth?”

      “When the beam of light hit the atmosphere, it would heat a pocket of air to millions of degrees in a fraction of a second. That air would turn to plasma and start dumping its heat as a flood of x-rays in all directions. Those x-rays would heat up the air around them, which would turn to plasma itself and start emitting infrared light. It would be like a hydrogen bomb going off, only much more violent.”

      So it is REALLY bright!

      Please remember to vote!

    • Photo: Dr. Pramod Kumar

      Dr. Pramod Kumar answered on 8 Nov 2016:


      As you know the sun is 93 million miles away from the earth but still looks like a big ball. But it is not really unusually bright compared to other stars. It is just closer to us. Other stars can be seen in the universe are likely to be brighter than the sun, but more than 100,000 times as far away.

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