Bergelmir.space

Irregular moon of Saturn (retrograde) · Outer Saturnian system · Norse group

Bergelmir

Saturn XXXVIII · S/2004 S 15

A six-kilometre backwards moon named for the giant who survived the flood of Ymir’s blood.

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Bergelmir at a glance
Object typeIrregular, retrograde moon of Saturn[1]
GroupNorse group[2]
DiscoveredDec. 12, 2004 — one of 12 Saturn moons found that day[2]
NamedApril 2007, after a giant of Norse myth[1]
Diameter≈ 6 km[1]
Rotation period≈ 8.13 hours[1]
Mean distance≈ 19.3 million km from Saturn[3]
Orbital period≈ 999 days[3]
Inclination≈ 159° (retrograde)[3]
Eccentricity≈ 0.15[3]

A backwards moon of Saturn

Bergelmir is about 6 km across and orbits Saturn retrograde, with a rotation period of about 8.13 hours.[1] It belongs to the Norse group of retrograde moons.[2]

One of twelve in one day

Bergelmir was found on 12 December 2004 — one of 12 Saturnian moons found that day by Sheppard, Jewitt and Kleyna using the Subaru telescope on Mauna Kea. Brian Marsden computed the orbits.[2]

The Norse group

As of April 2026 the Norse group has 210 known members, by far the largest of Saturn’s groups. They are unlikely to be a single collisional family.[4]

The survivor giant

Named in April 2007, Bergelmir was a giant of Norse myth and grandson of the primordial giant Ymir. He and his wife were the only giants to survive the flood of blood when Ymir was killed by Odin and his brothers.[1]

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Orbit

Bergelmir orbits backwards between about 16.5 and 22.1 million km from Saturn, taking about 999 days.[3]

Saturn Titan (1.22 million km)Phoebe (12.93 million km) farthest ≈ 22.1 million km closest ≈ 16.5 million km
Top-down orbit of Bergelmir to scale, computed from JPL orbital elements (a ≈ 19.27 million km, e ≈ 0.145).[3] Titan and Phoebe orbits shown for comparison.[3] Mean orbital elements; the real orbit is tilted steeply and shifts over time, so this top-down view flattens it onto one plane.

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Ymir, Bergelmir and the flood of blood

The Norse creation story behind a moon’s name.

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Saturn’s 293 moons

How Saturn became the moon champion of the Solar System.

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An eight-hour day

Bergelmir’s rotation and what it tells us.

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Sources

  1. Bergelmir (moon) — Wikipedia
  2. Bergelmir — NASA Science
  3. Planetary Satellite Mean Elements — NASA JPL Solar System Dynamics
  4. Norse group — Wikipedia
  5. Ymir — Wikipedia
  6. Saturn — Wikipedia

Figures are rounded; where sources differ we note it. Spotted an error? Tell us.