Pollux size and scale context

Pollux is the brightest star in Gemini and the nearest giant star to the Sun. It has already left the main sequence and swelled into an orange giant, making it a useful nearby preview of what a Sun-like star looks like after exhausting core hydrogen. Read its scale context, comparisons, and journey links on the canonical object page.

JupiterGas giant planet·140,000 km

SunG-type main-sequence star·1.39 million km

Procyon AF-type subgiant star·2.84 million km

PolluxOrange giant star·12.5 million km

Sagittarius A*Supermassive black hole·24.5 million km

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Between the smallest and the largest, perspective is everything.

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 turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

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Planets of the Solar System Stars of the Universe Black holes Subatomic scale

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Between the smallest and the largest, perspective is everything.

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 turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

Editorial

Solar System Planets From Electron to Atoms Stars To Scale Birth And Death Of Stars Black Holes To Scale

Views

Planets of the Solar System Stars of the Universe Black holes Subatomic scale

Open Scale of Space Browse all comparisons

Stars

Procyon A

Procyon A is the bright F-type primary of the Procyon binary and has begun to swell beyond an ordinary main-sequence star. Its faint companion, Procyon B, is already a white dwarf, so the pair gives astronomers a nearby before-and-after snapshot of stellar evolution in one system.

Scale fact2.84 million kmdiameter

Object class: F-type subgiant star
Mass: ~1.48 solar masses
Host: Procyon system
Estimated age: ~1.9 billion years
Composition: Hydrogen and helium
Temperature: ~6,580 K surface

Stars

Pollux

Scale fact12.5 million kmdiameter

Object class: Orange giant star
Mass: ~1.9 solar masses
Temperature: ~4,810 K surface
Estimated age: ~0.9–1.7 billion years
Composition: Hydrogen and helium

Black holes

Sagittarius A*

Sagittarius A* is the supermassive black hole at the center of the Milky Way. Event Horizon Telescope observations imaged the glowing material around it, resolving a radio source about 52 million kilometers across around a black hole of roughly 4.3 million solar masses.

Scale fact24.5 million kmevent horizon diameter

Object class: Supermassive black hole
Host: Milky Way
Mass: ~4.3 million solar masses