The 2017 solar eclipse may prove the sun is bigger than we think
Eclipse models suggest that the sun's photosphere is slightly larger than the value commonly used. Eclipse measurements could help determine for sure. Here, an annular eclipse is visible. Credit: NASA
A growing number of researchers think that the sun is actually larger than commonly thought.
Scientists don't know the sun's size as precisely as the details of the Earth and moon, making it a sticking point for perplexed eclipse modelers.
Xavier Jubier creates detailed models of solar and lunar eclipses that work with Google Maps to show precisely where the shadow of the moon will fall on the Earth, and what the eclipse will look like at each point. He came to realize there was something off about the sun's measurements as he matched his eclipse simulations with actual photos. The photos helped him identify exactly where an observer had been for historical eclipses — but those precise eclipse shapes only made sense if he scaled up the sun's radius by a few hundred kilometers.
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