Neptune's Deep Chemistry

  title={Neptune's Deep Chemistry},
  author={William B. Hubbard},
  pages={1279 - 1280}
  • W. Hubbard
  • Published 28 February 1997
  • Physics, Geology
  • Science
Molecules such as C2H2 and C2H6 have been observed in the atmosphere of Neptune, one of the giant planets composed mostly of hydrogen and helium. Planetary scientists have puzzled over whether these hydrocarbons are formed as ultraviolet light from the sun induces photochemical reactions in atmospheric methane. In his Perspective, Hubbard discusses simulations reported in the same issue by Ancilotto et al. (p. 1288) suggesting that C2H6 may be produced by high-pressure chemical reactions deep… 

Superionic and metallic states of water and ammonia at giant planet conditions.

The phase diagrams of water and ammonia were determined by constant pressure ab initio molecular dynamic simulations at pressures (30 to 300 gigapascal) and temperatures (300 to 7000 kelvin) of relevance for the middle ice layers of the giant planets Neptune and Uranus to improve the understanding of the properties of the middle icy layers.

New windows on earth and planetary interiors

Abstract Recent diamond-anvil cell experiments are providing windows of unprecedented clarity on the interiors of the Earth, other planets, and their moons from high P-T studies of the materials that

Catalytic behaviour of dense hot water.

This work shows that water has an unexpected role in catalysing complex explosive reactions--contrary to the current view that it is simply a stable detonation product, and suggests that water may catalyse reactions in other explosives and in planetary interiors.

Electronic bandgap of water in the superionic and plasma phases

Water has been proposed to be one of the main compositions of icy giant planets like Neptune and Uranus. Its thermodynamic states and transport properties at extremes are of interest not only to

Kinetic Isotope Effect in Low-Energy Collisions between Hydrogen Isotopologues and Metastable Helium Atoms: Theoretical Calculations Including the Vibrational Excitation of the Molecule

The results confirm a recently observed substantial quantum kinetic isotope effect and reveal that the change of the rotational or vibrational state of the molecule can strongly enhance or suppress the reaction.

Effects of high pressure on molecules.

  • R. Hemley
  • Chemistry
    Annual review of physical chemistry
  • 2000
Recent high-pressure studies reveal a wealth of new information about the behavior of molecular materials subjected to pressures well into the multimegabar range (several hundred gigapascal),



The ice layer in Uranus and Neptune—diamonds in the sky?

Many of the current models of Uranus and Neptune postulate a three-layer structure, consisting of an inner rocky core, a middle ‘ice’ layer of fluid, H2O, CH4, NH3 and an outer hydrogen–helium layer

Dissociation of Methane into Hydrocarbons at Extreme (Planetary) Pressure and Temperature

Constant-pressure, first-principles molecular dynamic simulations were used to investigate the behavior of methane at high pressure and temperature, and suggest that, below 100 gigapascals, methane dissociates into a mixture of hydrocarbons, and it separates into hydrogen and carbon only above 300 gigapascalals.

Neptune and Triton

The first reconnaissance of all the major planets of the Solar System culminated in the Voyager 2 encounter with Neptune in August 1989. Neptune itself was revealed as a planet with gigantic active

The Galileo Probe Mass Spectrometer: Composition of Jupiter's Atmosphere

The measured ratio of deuterium to hydrogen (D/H) indicates that this ratio is greater in solar-system hydrogen than in local interstellar hydrogen, and the 3He/4He ratio provides a new value for protosolar (solar nebula) helium isotopes.