Uranus and Neptune Could Be Magma Worlds, Researchers Suggest

WHO:

Phys.org - Researchers from the University of California are involved in the study.

WHAT:

Gizmodo - A new study suggests that Uranus and Neptune may be better described as “magma-ocean giants” rather than traditional ice giants.

Gizmodo - The study was submitted to The Astrophysical Journal.

Gizmodo - Voyager 2 discovered 11 new moons and two new rings around Uranus.

Gizmodo - Voyager 2 discovered six new moons and four ring arcs around Neptune.

WHERE:

Phys.org - Uranus and Neptune are located in the outer solar system.

Gizmodo - Voyager 2 flew by Uranus within 50,640 miles (81,500 kilometers) and passed Neptune’s north pole.

WHEN:

Gizmodo - Voyager 2 flew by Uranus on January 24, 1986, and passed Neptune on August 25, 1989.

WHY:

Phys.org - The long-standing hypothesis about Uranus and Neptune's interiors suggests they have an icy mantle beneath hydrogen-helium atmospheres.

Gizmodo - The researchers argue that the three-layer model of an ice giant’s interior structure is not the only explanation for the properties of Uranus and Neptune.

HOW:

Gizmodo - The researchers simulated different models for the interior processes and composition of Uranus and Neptune.

Gizmodo - The model suggests that at high pressures, hydrogen gas can dissolve into magma, forming a well-mixed fluid.

(UPDATED June 27, 2026 13:22 UTC)

Researchers from the University of California have released a new study suggesting that Uranus and Neptune might be better classified as “magma-ocean giants” instead of traditional ice giants, with their findings submitted to The Astrophysical Journal. The study challenges the long-standing hypothesis about the planets' interiors, which posited an icy mantle beneath hydrogen-helium atmospheres, and indicates that high-pressure conditions can cause hydrogen gas to dissolve into magma, creating a well-mixed fluid. Additionally, Voyager 2's historic flybys revealed new moons and rings around both planets, with 11 new moons and two rings discovered at Uranus and six new moons along with four ring arcs found at Neptune.