Scale Comparison
Arcturus is an orange giant about 25 times the Sun’s diameter.
Arcturus has roughly the Sun’s mass but has exhausted hydrogen in its core and expanded. Its cooler surface covers enough area for the star to emit far more light overall.
Objects
The Sun is the star at the center of the Solar System and the source of almost all the energy reaching its planets. It fuses about 600 million metric tons of hydrogen each second, and energy released in the core takes on the order of 100,000 years to work its way out to the visible surface.
Arcturus is a bright orange giant and the brightest star in the northern celestial hemisphere. It also races unusually fast across the sky for such a bright star, shifting by about two arcseconds per year because of its high motion relative to the Sun.
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About
Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.
Guides explain selected parts of that range, while focused views filter the objects by subject.