Well. There’s the biggest star we have seen to date:
Size comparison of a hypothetical quasi-star/black hole star (diameter of ~10 billion kilometres or ~7,187 solar diameters, mass of 1000+ solar masses) and several known giant stars: Stephenson 2-18 (~2150 solar diameters), VY Canis Majoris (~1420 solar diameters, ~17 solar masses), Betelgeuse (~887 solar diameters, ~11.6 solar masses), the Pistol Star (~306 solar diameters, ~27.5 solar masses), Rigel (~78.9 solar diameters, ~23 solar masses), and R136a1 (~35.4 solar diamaters, ~265 solar masses). Image credit: Wikimedia Commons/Sauropodomorph (CC0 1.0)
And then there’s the biggest black hole to date:
The largest black hole ever discovered. Estimates of its mass and size make this black hole a true behemoth, and it is unlike anything in our galaxy or in any of the galaxies in our galactic neighborhood. The mass of the central black hole is estimated to be 100 billion times larger than the sun. The supermassive black hole is even more massive than some galaxies, and is about 10% the mass of the entire Milky Way. The event horizon of the black hole has a diameter of 590 billion kilometres, or about 100 times the distance between the sun and Pluto. That little dot in the middle is the orbit of Neptune.
And then there’s the largest galaxy discovered to date:
Its full span is 5.5 million light-years across: nearly double the Local Group’s full extent.
Then there’s superclusters of galaxies:
Finally, there’s Quipu:
The colored dots represent different superstructures out to 800 million light-years from Earth. The red dots denote Quipu, the largest known structure in the nearby universe. Yellow is Sculptor-Pegasus superstructure, green is Serpens-Corona Borealis, purple is Hercules and blue is Shapley. Image via Böhringer et al. Astronomy and Astrophysics, 2025.
There are 185 galaxy clusters within these five superstructures. Quipu alone has 68 galaxy clusters.