How many degrees of arc is the width of the solar disk in Mercury's sky? Could you see solar flares (with protection) without lenses?

2 Answers

  • 8 months ago
    Favourite answer


    Aphelion 69,816,900 kmPerihelion 46,001,200 km

    Mean radius 2,439.7 km

    SunMean radius 696,392 km

    mean distance mercury to sun is average of Aphelion and Perihelion

    which is about (69.8+46)/2 = 57.9e6 km

    need to subtract radius of mercury to get surface distance to sun

    57.9e6 km – 2000 km = 57.9e6 km

    so the sun subtends 696e3 km at a distance of 57.9e6 km

    using trig, half the angle = arctan (696e3/(0.5)57.9e6)) = 1.38º

    twice that is 2.75º

    as to visibility, some are visible on earth to the naked eye, so certainly even more would be visible on mercury.

  • 8 months ago

    2.5 times as seen from Earth. The Sun's width is an average of 30 seconds of SRC, so 3.5 time would be 1.5° degrees of adv. 1° = 60 minutes.   

    I used the AVERAGE diameter of the Sun. The Sun can be 34' wide from Earth because the distance of Earth from the Sun varies by 5 million kilometers, 3.8 million miles. 

    No, you would NOT be able to see solar flares without lenses or filters. 

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