[To Scale] The Sun and Betelgeuse


So I snapped this photo from my backyard earlier. Pretty nifty I’d say.

The bland solar surface suggests the coming of a new solar minimum … which is the second in my lifetime, and I’m far too inexperienced to remark more on.


Other than the sun, the star that humanity has the most detailed photo of is Betelgeuse, Alpha Orionis. It’s a luminous red supergiant with designated spectral type M1 Ia–ab, at an effective surface temperature of 3590K. [https://arxiv.org/abs/1109.4562]

Thanks ALMA. See you later

We have a photo of it thanks to the facts that it’s bright, big, and galactically not so far away. Not so close that we might share the same post code, but yeah, close enough for photography.

// Before we progress, note that the color temperatures need a bit of work … the sun appears in my lens as orange mostly due to my filter’s bias. At 5760K, the sun should appear yellowish white to human eyes.

Anyways, let’s juxtapose their centers on the same plane, and do a quick size comparison. How much do you imagine Betelgeuse is bigger than the sun, which has an average radius of 7*10^8 meters?

Do you see the 9-pixel sun?


Before writing this (and procrastinating more for tomorrow’s exam), I was about to complain that the sun takes up too little a corner in my sensor, but no, remember, the distance is just right.

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