Diamond Rain on Uranus and Neptune

The Jeweled Weather of the Ice Giants

By Google Arts & Culture

Mackenzie White

Neptune, From the collection of: NASA
Uranus, From the collection of: NASA
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Explore 3D models of Uranus and Neptune.

Solar System Montage - High Resolution 2001 Version (2001-03-29) by NASA/JPLNASA

Our Solar System's Giants

Like their cosmic neighbors Jupiter and Saturn, Uranus and Neptune are massive worlds with thick atmospheres and strong magnetic fields. These four giants are the farthest planets from the Sun in our solar system, orbiting the star on timescales much longer than our Earth year.

Differing from their larger siblings in composition and structure, Uranus and Neptune fall into a distinct class of planets known as the "ice giants" while hydrogen and helium-enriched bodies (i.e., Jupiter and Saturn) are our Solar System’s “gas giants.” 

Helium-Shrouded Planets Artist Concept (2015-06-11) by NASA/JPL-CaltechNASA

Whereas the cores of gas giants represent only a small fraction of the body’s total mass, Uranus and Neptune carry most of their mass in their cores and contain heavier compounds of carbon, nitrogen, and oxygen.

Webb Explained Slide 14 by Credits: Left: NASA/JPL-Caltech - Right: NASANASA

Their atmospheres are also distinct, creating a unique environment in which trace amounts of methane react with sunlight, giving the planets their blueish coloring.

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Voyager 2

As the furthest two major planets in our Solar System, they are challenging to study and have only received a visit from a single space mission, NASA's Voyager 2. Learn more about this mission here.

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Hubble Space TelescopeNASA

Despite this obstacle, scientists have made astonishing discoveries about these distant worlds using Voyager 2, the Hubble Telescope, and ground-based methods. Learn more about Hubble here.

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From their similar size (approximately fifteen times the size of Earth) to their rapid spin speeds, the planets are a striking duo in our diverse universe. 

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Ul-10/89 (1989-08)LIFE Photo Collection

In addition to these directly observable characteristics, at the immense pressures inside these giants, familiar materials can transform into exotic forms.

One possible phenomenon is particularly dazzling: deep within Neptune and Uranus, it may rain diamonds.

LIFE Photo Collection

Supported by laboratory simulations, researchers have developed models of the planets' atmospheres to explore what may be causing this unusual weather in their centers deep beneath their hazy shields. 

Voyager Mission To Uranus (1986)LIFE Photo Collection

While they may have earned their titles as "ice giants" from their exteriors, it is primarily the ice obscured in the middle layers of Uranus and Neptune that creates their remarkable forms of precipitation.

This picture of Neptune was produced from the last whole planet images taken through the filters on NASA's Voyager 2 angle camera. (1998-10-30) by NASA/JPL and Voyager 2NASA

For example, under Neptune's vibrant cobalt blue shell, gravity within a massively thick ice layer squeezes water, ammonia, and methane to create extremely high densities and temperatures. 

Pressures in this region grow to over a million times Earth's atmospheric pressure, compressing the "ices" into a scorching, condensed fluid.

A Sunny Outlook for Weather on Exoplanets Artist Concept (2014-09-24) by NASA/JPL-CaltechNASA

These conditions create an environment in which ammonia and methane can chemically react. Here, methane's carbon and hydrogen atoms separate and can squeeze into diamonds—or so researchers suspect. Then, if the diamonds are heavy enough, they can fall as rain on the planet.

This Voyager 2 high resolution color image provides obvious evidence of vertical relief in Neptune's bright cloud streaks. (1989-08-26) by JPLNASA

Current estimates of formation rates indicate that diamonds may grow over millions of years on Uranus and Neptune, potentially creating meter-sized gems.

Uranus as seen by NASA Voyager 2 (1986-12-18) by NASA/JPL-CaltechNASA

Unfortunately, due to the tremendous heat and pressure, there is currently no way for humans to venture into these conditions and witness their cascading treasures.

Webb Explained Slide 14 by Credits: Left: NASA/JPL-Caltech - Right: NASANASA

Though diamond rain may occur on both planets, critical differences in the structure of the ice giants make the rain form and fall at distinctive heights within their atmospheres.

Uranus, From the collection of: NASA
Neptune, From the collection of: NASA
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While they may be planetary siblings, their diamond disparities are only the beginning. From snow produced by Neptune's more active skies to the thicker haze clouding Uranus' slower atmosphere, the two worlds are unique and chemically complex.

One Voyager Out, One Voyager In Artist Concept (2013-09-12) by NASA/JPL-CaltechNASA

Continued study of the shared wonders and diverging settings on Uranus and Neptune may hold the answers to some of planetary science's most pressing questions and intriguing mysteries.

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The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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