Helene size and scale context

Helene is a small Trojan moon of Saturn that shares Dione’s orbit, holding a stable position about 60 degrees ahead of the much larger moon. Cassini revealed an irregular world with smooth-looking deposits, grooves, and impact scars. Read its scale context, comparisons, and journey links on the canonical object page.

PanShepherd moon·34.6 km

AtlasInner ring moon·40.8 km

HeleneTrojan moon·45.2 km

243 IdaS-type main-belt asteroid·59.8 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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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

Moons

Atlas

Atlas is a small inner moon of Saturn with a broad, smooth equatorial ridge that gives it a flying-saucer shape. The ridge is probably built from ring particles swept up near the edge of Saturn's A ring.

Scale fact40.8 kmmaximum extent

Object class: Inner ring moon
Composition: Porous water ice and ring material
Temperature: 81 K surface
Mass: ~5.49 trillion tonnes
Host: Saturn

Moons

Helene

Scale fact45.2 kmmaximum extent

Object class: Trojan moon
Host: Saturn

Asteroids

243 Ida

243 Ida is the elongated main-belt asteroid that NASA's Galileo spacecraft flew past in 1993, discovering that it has a tiny moon of its own – Dactyl. Ida became the first asteroid known to have a natural satellite, proving that even small bodies can hold companions.

Scale fact59.8 kmmaximum extent

Object class: S-type main-belt asteroid
Mass: ~42 trillion tonnes
Estimated age: ~4.5 billion years
Composition: Silicate rock with metal