Halley's Comet size and scale context

Halley's Comet nucleus is the solid core of the Solar System's most famous periodic comet. ESA’s Giotto mission found it to be darker than coal and among the darkest known objects in the Solar System, with jets blasting material from localized active regions. Read its scale context, comparisons, and journey links on the canonical object page.

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

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

Open Scale of Space

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

Comets

67P/Churyumov–Gerasimenko

67P/Churyumov–Gerasimenko is the comet nucleus studied in unrivaled detail by ESA’s Rosetta mission. Rosetta detected molecular oxygen streaming from the comet, a surprising result that suggests some of its ice preserves very early Solar System chemistry.

Scale fact6 kmmaximum extent

Object class: Comet nucleus
Mass: ~10 billion tonnes
Host: Solar System
Estimated age: ~4.5 billion years
Composition: Water ice, dust, frozen volatiles

Comets

Halley's Comet

Scale fact11 kmmean diameter

Object class: Comet nucleus
Mass: ~220 billion tonnes
Host: Solar System
Estimated age: ~4.5 billion years
Composition: Water ice, dust, frozen volatiles

Stellar remnants

Crab Pulsar

The Crab Pulsar is the neutron-star core left behind by the explosion that also created the Crab Nebula. It spins about 30 times each second, and its magnetic engine drives much of the nebula’s glow by pouring particles and radiation into the surrounding wreckage.

Scale fact20 kmdiameter

Object class: Pulsar
Mass: ~1.4 solar masses
Host: Crab Nebula
Estimated age: ~970 years
Composition: Neutron-degenerate matter