Observable universe
The observable universe is the region from which light or other signals have had time to reach us since the early universe.
28.21 GpcDiameterWorlds apart
Observable universe vs Milky Way
What are they, and what does the difference actually look like?
Two things. One honest scale.
Meet the pair
What these two things are
Milky Way
The Milky Way is a spiral galaxy containing hundreds of billions of stars, including our Solar System.
30.66 kpcDiameterObservable universe has about 920,000 times the diameter of Milky Way.
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Observable universe28.21 GpcDiameter
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Milky Way30.66 kpcDiameter
Inset ×320,000Milky Way is too small to see clearly at this scale. The ring marks its position; only the inset is enlarged.
Measurements, assumptions & sources +
Observable universe
About 92 billion light-years across in present-day comoving distance. Space expanded while the light travelled. The 13.8-billion-year age is a time, not its radius divided by light speed. The total universe may be far larger, possibly infinite.
NASA — How big is space? (2025)
The marked diameter is calibrated. Unmeasured illustration details are representative.
Milky Way
A rounded 100,000 light-year span of the stellar disk. Faint stars and the dark-matter halo extend farther; galaxies have no crisp rim.
The marked diameter is calibrated. Unmeasured illustration details are representative.
Change the comparison
Put something else beside it.
Measurement details
Why these numbers?
The visual compares diameter with diameter. The records below preserve each value’s basis and caveats.
Observable universe
28.21 GpcDiameter · cosmological estimate
About 92 billion light-years across in present-day comoving distance. Space expanded while the light travelled. The 13.8-billion-year age is a time, not its radius divided by light speed. The total universe may be far larger, possibly infinite.
Milky Way
30.66 kpcDiameter · approximate
A rounded 100,000 light-year span of the stellar disk. Faint stars and the dark-matter halo extend farther; galaxies have no crisp rim.
- Comparing
- Diameter ↔ Diameter
- Relative size
- Observable universe is larger on this measurement by a factor of about 920,000.
How to read the visual
The labelled spans and stored measurements determine the scale; unmeasured illustration details do not.
- Observable universe is labelled cosmological estimate; treat the displayed value as a comparison anchor rather than false precision.
- Milky Way is labelled approximate; treat the displayed value as a comparison anchor rather than false precision.
There’s always another scale
Follow your curiosity.
SpaceObservable universe28.21 GpcThe observable universe is the region from which light or other signals have had time to reach us since the early universe.SpaceMilky Way30.66 kpcThe Milky Way is a spiral galaxy containing hundreds of billions of stars, including our Solar System.
SpaceLocal Group3.066 MpcThe Local Group is a collection of galaxies that includes the Milky Way, Andromeda, and several smaller galaxies.
Fundamental physicsPlanck length1.616 × 10⁻³⁵ mThe Planck length is a scale formed from fundamental physical constants.
SpaceSun1,391,000 kmThe Sun is the star at the centre of the Solar System.
SpaceDistance to the galactic centre7.972 kpcThis is the distance from the Solar System to the centre of the Milky Way galaxy.SpaceAndromeda galaxy79.72 kpcThe Andromeda galaxy, also called M31, is the nearest large spiral galaxy to the Milky Way.Side by side
Another point of view.
