Quasi-Stars: Black Holes at the Core of the Universe’s Largest Stars
This is a story of extremes.
Quasi-stars are larger than any stars we’ve ever discovered. They tower not only above our sun — which, despite making up over 99% of the Solar System’s mass is only a yellow dwarf — but they overshadow all other dwarf stars, giant stars, supergiant stars, and even the impressive hypergiants. UY Scuti is classified as a red supergiant with a radius 1,700 times that of the sun. Where the sun is hundreds of thousands of miles across, UY Scuti is hundreds of millions of miles in breadth. It’s a stunning red orb whose main body and surrounding atmosphere would bleed out of our Solar System altogether, unable to be contained in our paltry, simple space. It’s also the largest star we’ve ever encountered and is found in the night sky as an ornament in a diamond shaped constellation just above the region of Sagittarius. And yet even UY Scuti is small and childlike in comparison to quasi-stars.
Inflating to an enormous 7,000 times larger than the sun, the diameter of these stars reaches well into the billions. The largest are thought to be over 6 billion miles of hot, crackling, fuming gas and energy. But the main difference between everyday stars and quasi-stars isn’t in size, it’s in the process at their cores. An average star will use fusion as its energy source — like the sun…
