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Planck length vs Observable universe: length comparison

The diameter of the observable universe is about 5.39 × 10⁶¹ times the Planck length. Selected basis: approximate values.

Planck length
Length
Observable universe
Diameter
Scale
Planck length
1.616 × 10⁻³⁵ mLength
0 - shared origin

The ring marks the true-scale position of the Planck length; it does not show its width. Only the inset is enlarged (×1.72 × 10⁶¹).

Observable universe
28.21 GpcDiameter
0 - shared origin

Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.

In perspective5.39 × 10⁶¹ times
Measurements, assumptions & sources

Planck length

1.616 × 10⁻³⁵ m - Length; theoretical.

The Planck length is a scale formed from fundamental physical constants. It marks a regime where present theories of gravity and quantum physics are expected to need a unified description.

A theoretical scale formed from the speed of light, reduced Planck constant and gravitational constant. It is not experimentally established as the smallest possible length. The area and volume are derived mathematical scales.

NIST — 2022 CODATA fundamental constants

Observable universe

28.21 Gpc - Diameter; cosmological estimate.

The observable universe is the region from which light or other signals have had time to reach us since the early 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)

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Fundamental physicsPlanck length1.616 × 10⁻³⁵ mThe Planck length is a scale formed from fundamental physical constants.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.Fundamental physicsProton1.682 fmA proton is a positively charged particle found in the nucleus of atoms, made up of quarks.MicroscopicHydrogen atom105.8 pmA hydrogen atom is the simplest neutral atom, with one proton in its nucleus and one electron around it.Fundamental physicsPlanck mass21.76 µgThe Planck mass is a theoretical mass scale derived from fundamental constants, significant in discussions of quantum gravity.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.

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All comparisons ↗
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Planck length vs Observable universe