Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Earth shaped by primordial H2 atmospheres

Abstract

Earth’s water, intrinsic oxidation state and metal core density are fundamental chemical features of our planet. Studies of exoplanets provide a useful context for elucidating the source of these chemical traits. Planet formation and evolution models demonstrate that rocky exoplanets commonly formed with hydrogen-rich envelopes that were lost over time1. These findings suggest that Earth may also have formed from bodies with hydrogen-rich primary atmospheres. Here we use a self-consistent thermodynamic model to show that Earth’s water, core density and overall oxidation state can all be sourced to equilibrium between hydrogen-rich primary atmospheres and underlying magma oceans in its progenitor planetary embryos. Water is produced from dry starting materials resembling enstatite chondrites as oxygen from magma oceans reacts with hydrogen. Hydrogen derived from the atmosphere enters the magma ocean and eventually the metal core at equilibrium, causing metal density deficits matching that of Earth. Oxidation of the silicate rocks from solar-like to Earth-like oxygen fugacities also ensues as silicon, along with hydrogen and oxygen, alloys with iron in the cores. Reaction with hydrogen atmospheres and metal–silicate equilibrium thus provides a simple explanation for fundamental features of Earth’s geochemistry that is consistent with rocky planet formation across the Galaxy.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Summary of thermodynamic calculations.
Fig. 2: Comparison of oxygen fugacities in the Solar System.
Fig. 3: Proposed model for the evolution of Earth’s progenitor embryos.

Similar content being viewed by others

Data availability

Example model results are available as Supplementary tables.

Code availability

The Python code used for the models shown in Fig. 1 in this study is available at GitHub: https://github.com/eyoungucla/chems/blob/main/Exoplanet_atmosphere_model_vMCMC_coreT_3000K_dist.py.

References

  1. Bean, J. L., Raymond, S. N. & Owen, J. E. The nature and origins of sub-Neptune size planets. J. Geophys. Res. Planets 126, e06639 (2021).

    Article  Google Scholar 

  2. Wetherill, G. W. Accumulation of the terrestrial planets. in IAU Colloquium 52: Protostars and Planets (eds Gehrels, T. & Matthews, M. S.) 565 (Univ. Arizona Press, 1978).

  3. Rubie, D. et al. Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion of water. Icarus 248, 89–108 (2015).

    Article  ADS  CAS  Google Scholar 

  4. Albarède, F. Volatile accretion history of the terrestrial planets and dynamic implications. Nature 461, 1227–1233 (2009).

    Article  ADS  PubMed  Google Scholar 

  5. Cartier, C. & Wood, B. J. The role of reducing conditions in building Mercury. Elements 15, 39–45 (2019).

    Article  Google Scholar 

  6. Dauphas, N. The isotopic nature of the Earth’s accreting material through time. Nature 541, 521–524 (2017).

    Article  ADS  CAS  PubMed  Google Scholar 

  7. Sikdar, J. & Rai, V. K. Si–Mg isotopes in enstatite chondrites and accretion of reduced planetary bodies. Sci. Rep. 10, 1273 (2020).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  8. Javoy, M. The integral enstatite chondrite model of the Earth. Geophys. Res. Lett. 22, 2219–2222 (1995).

    Article  ADS  CAS  Google Scholar 

  9. Nittler, L. R. et al. The major-element composition of Mercury’s surface from messenger X-ray spectrometry. Science 333, 1847–1850 (2011).

    Article  ADS  CAS  PubMed  Google Scholar 

  10. Shepard, M. K. et al. A radar survey of M- and X-class asteroids. III. Insights into their composition, hydration state, & structure. Icarus 245, 38–55 (2015).

    Article  ADS  CAS  Google Scholar 

  11. Zellner, B., Leake, M., Morrison, D. & Williams, J. The E asteroids and the origin of the enstatite achondrites. Geochim. Cosmochim. Acta 41, 1759–1767 (1977).

    Article  ADS  CAS  Google Scholar 

  12. Piani, L. et al. Earth’s water may have been inherited from material similar to enstatite chondrite meteorites. Science 369, 1110–1113 (2020).

    Article  ADS  CAS  PubMed  Google Scholar 

  13. Petigura, E. A., Howard, A. W. & Marcy, G. W. Prevalence of Earth-size planets orbiting Sun-like stars. Proc. Natl Acad. Sci. USA 110, 19273–19278 (2013).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  14. Weiss, L. M. & Marcy, G. W. The mass–radius relation for 65 exoplanets smaller than 4 Earth radii. Astrophys. J. 783, L6 (2014).

    Article  ADS  Google Scholar 

  15. Fulton, B. J. et al. The California–Kepler survey. III. A gap in the radius distribution of small planets. Astrophys. J. 154, 109 (2017).

    Google Scholar 

  16. Berger, T. A., Huber, D., Gaidos, E., van Saders, J. L. & Weiss, L. M. The Gaia–Kepler Stellar Properties Catalog. II. Planet radius demographics as a function of stellar mass and age. Astron. J. 160, 108 (2020).

    Article  ADS  Google Scholar 

  17. Owen, J. E. & Wu, Y. Kepler planets: a tale of evaporation. Astrophys. J. 775, 105 (2013).

    Article  ADS  Google Scholar 

  18. Gupta, A. & Schlichting, H. E. Sculpting the valley in the radius distribution of small exoplanets as a by-product of planet formation: the core-powered mass-loss mechanism. Mon. Not. R. Astron. Soc. 487, 24–33 (2019).

    Article  ADS  PubMed  PubMed Central  Google Scholar 

  19. Ginzburg, S., Schlichting, H. E. & Sari, R. Super-Earth atmospheres: self-consistent gas accretion and retention. Astrophys. J. 825, 29 (2016).

    Article  ADS  Google Scholar 

  20. Schlichting, H. E. & Young, E. D. Chemical equilibrium between cores, mantles, and atmospheres of super-Earths and sub-Neptunes, and implications for their compositions, interiors and evolution. Planet. Sci. J. 9, 127 (2022).

    Article  Google Scholar 

  21. Solomatov, V. S. Magma Oceans and Primordial Mantle Differentiation Vol. 9 (Elsevier, 2009).

  22. Young, E. D. et al. Near-equilibrium isotope fractionation during planetesimal evaporation. Icarus 323, 1–15 (2019).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  23. Mukhopadhyay, S. Early differentiation and volatile accretion recorded in deep-mantle neon and xenon. Nature 486, 101–104 (2012).

    Article  ADS  CAS  PubMed  Google Scholar 

  24. Mukhopadhyay, S. & Parai, R. Noble gases: a record of Earth’s evolution and mantle dynamics. Annu. Rev. Earth Planet. Sci. 47, 389–419 (2019).

    Article  ADS  CAS  Google Scholar 

  25. Williams, C. D. & Mukhopadhyay, S. Capture of nebular gases during Earth’s accretion is preserved in deep-mantle neon. Nature 565, 78–81 (2019).

    Article  ADS  CAS  PubMed  Google Scholar 

  26. Lammer, H. et al. Constraining the early evolution of Venus and Earth through atmospheric Ar, Ne isotope and bulk K/U ratios. Icarus 339, 113551 (2020).

    Article  Google Scholar 

  27. Sharp, Z. & Olson, P. Multi-element constraints on the sources of volatiles to earth. Geochim. Cosmochim. Acta 333, 124–135 (2022).

    Article  ADS  CAS  Google Scholar 

  28. Kurokawa, H. et al. Mars’ atmospheric neon suggests volatile-rich primitive mantle. Icarus 370, 114685 (2021).

    Article  CAS  Google Scholar 

  29. Peron, S. & Mukhopadhyay, S. Krypton in the Chassigny meteorite shows Mars accreted chondritic volatiles before nebular gases. Science 377, 320–324 (2022).

    Article  ADS  CAS  PubMed  Google Scholar 

  30. Dauphas, N. & Pourmand, A. Hf–W–Th evidence for rapid growth of Mars and its status as a planetary embryo. Nature 473, 489–492 (2011).

    Article  ADS  CAS  PubMed  Google Scholar 

  31. Schlichting, H. E. Formation of close in super-Earths and mini-Neptunes: required disk masses and their implications. Astrophys. J. 795, L15 (2014).

    Article  ADS  Google Scholar 

  32. Johansen, A. et al. A pebble accretion model for the formation of the terrestrial planets in the Solar System. Sci. Adv. 7, eabc0444 (2021).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  33. Badro, J., Brodholt, J. P., Piet, H., Siebert, J. & Ryerson, F. Core formation and core composition from coupled geochemical and geophysical constraints. Proc. Natl Acad. Sci. USA 112, 12310–12314 (2015).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  34. Li, Y., Vočadlo, L., Sun, T. & Brodholt, J. P. The Earth’s core as a reservoir of water. Nat. Geosci. 13, 453–458 (2020).

    Article  ADS  CAS  Google Scholar 

  35. Wood, B. Accretion and core formation: constraints from metal-silicate partitioning. Phil. Trans. R. Soc. Lond. A 366, 4339–4355 (2008).

    ADS  CAS  Google Scholar 

  36. Seager, S., Kuchner, M., Hier-Majumder, C. A. & Militzer, B. Mass–radius relationships for solid exoplanets. Astrophys. J. 669, 1279–1297 (2007).

    Article  ADS  CAS  Google Scholar 

  37. Anderson, O. L., Dubrovinsky, L., Saxena, S. K. & LeBihan, T. Experimental vibrational Grüneisen ratio values for -iron up to 330 GPa at 300 K. Geophys. Res. Lett. 28, 399–402 (2001).

    Article  ADS  CAS  Google Scholar 

  38. Kuwayama, Y. et al. Equation of state of liquid iron under extreme conditions. Phys. Rev. Lett. 124, 165701 (2020).

    Article  ADS  CAS  PubMed  Google Scholar 

  39. Ikoma, M. & Genda, H. Constraints on the mass of a habitable planet with water of nebular origin. Astrophys. J. 648, 696–706 (2006).

    Article  ADS  CAS  Google Scholar 

  40. Kite, E. & Schaefer, L. Water on hot rocky exoplanets. Astrophys. J. Lett. 909, L22 (2021).

    Article  ADS  CAS  Google Scholar 

  41. Birch, F. Density and composition of mantle and core. J. Geophys. Res. 69, 4377–4388 (1964).

    Article  ADS  CAS  Google Scholar 

  42. Umemoto, K. & Hirose, K. Chemical compositions of the outer core examined by first principles calculations. Earth Planet. Sci. Lett. 531, 116009 (2020).

    Article  CAS  Google Scholar 

  43. Li, J., Chen, B., Mookherjee, M. & Morard, G. Carbon versus Other Light Elements in Earth’s Core 40–65 (Cambridge Univ. Press, 2019).

  44. Doyle, A. E., Young, E. D., Klein, B., Zuckerman, B. & Schlichting, H. E. Oxygen fugacities of extrasolar rocks: evidence for an Earth-like geochemistry of exoplanets. Science 366, 356–359 (2019).

    Article  ADS  CAS  PubMed  Google Scholar 

  45. Javoy, M. et al. The chemical composition of the Earth: enstatite chondrite models. Earth Planet. Sci. Lett. 293, 259–268 (2010).

    Article  ADS  CAS  Google Scholar 

  46. Dziewonski, A. M. & Anderson, D. L. Preliminary reference Earth model. Phys. Earth Planet. Inter. 25, 297–356 (1981).

    Article  ADS  Google Scholar 

  47. Sanloup, C., Fiquet, G., Gregoryanz, E., Morard, G. & Mezouar, M. Effect of Si on liquid Fe compressibility: implications for sound velocity in core materials. Geophys. Res. Lett. 31, L07604 (2004).

  48. Umemoto, K. & Hirose, K. Liquid iron–hydrogen alloys at outer core conditions by first-principles calculations. Geophys. Res. Lett. 42, 7513–7520 (2015).

    Article  ADS  CAS  Google Scholar 

  49. Kennett, B. L. N., Engdahl, E. R. & Buland, R. Constraints on seismic velocities in the Earth from traveltimes. Geophys. J. Int. 122, 108–124 (1995).

    Article  ADS  Google Scholar 

  50. Biersteker, J. B. & Schlichting, H. E. Losing oceans: the effects of composition on the thermal component of impact-driven atmospheric loss. Mon. Not. R. Astron. Soc. 501, 587–595 (2021).

    Article  ADS  CAS  Google Scholar 

  51. Biersteker, J. B. & Schlichting, H. E. Atmospheric mass-loss due to giant impacts: the importance of the thermal component for hydrogen–helium envelopes. Mon. Not. R. Astron. Soc. 485, 4454–4463 (2019).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  52. Stähler, S. C. et al. Seismic detection of the Martian core. Science 373, 443–448 (2021).

    Article  ADS  PubMed  Google Scholar 

  53. Brasser, R. The formation of Mars: building blocks and accretion time scale. Space Sci. Rev. 174, 11–25 (2013).

    Article  ADS  CAS  Google Scholar 

  54. Benz, W., Anic, A., Horner, J. & Whitby, J. A. The origin of Mercury. Space Sci. Rev. 132, 189–202 (2007).

    Article  ADS  CAS  Google Scholar 

  55. Riner, M. A., Bina, C. R., Robinson, M. S. & Desch, S. J. Internal structure of Mercury: implications of a molten core. J. Geophys. Res. Planets 113, E08013 (2008).

  56. Margot, J.-L., Hauck, S. A., Mazarico, E., Padovan, S. & Peale, S. J. Mercury’s Internal Structure 85–113 (Cambridge Univ. Press, 2018).

  57. Corgne, A., Keshav, S., Wood, B. J., McDonough, W. F. & Fei, Y. Metal–silicate partitioning and constraints on core composition and oxygen fugacity during Earth accretion. Geochim. Cosmochim. Acta 72, 574–589 (2008).

    Article  ADS  CAS  Google Scholar 

  58. Fegley, J. B. & Cameran, A. G. W. A vaporization model for iron/silicate fractionation in the Mercury protoplanet. Earth Planet. Sci. Lett. 82, 207–222 (1987).

    Article  ADS  CAS  Google Scholar 

  59. Schaefer, L. & Fegley, B. Chemistry of silicate atmospheres of evaporating super-Earths. Astrophys. J. 703, L113–L117 (2009).

    Article  ADS  CAS  Google Scholar 

  60. Hastie, J. & Bonnell, D. A predictive thermodynamic model of oxide and halide glass phase equilibria. J. Non Crystalline Solids 84, 151–158 (1986).

    Article  ADS  CAS  Google Scholar 

  61. Xiang, Y., Sun, D., Fan, W. & Gong, X. Generalized simulated annealing algorithm and its application to the thomson model. Phys. Lett. A 233, 216–220 (1997).

    Article  ADS  CAS  Google Scholar 

  62. Foreman-Mackey, D. et al. emcee v3: a Python ensemble sampling toolkit for affine-invariant MCMC. J. Open Source Softw. 14, 1864 (2019).

  63. Goodman, J. & Weare, J. Ensemble samplers with affine invariance. Commun. Appl. Math. Comput. Sci. 5, 65–80 (2010).

    Article  MathSciNet  MATH  Google Scholar 

  64. Kovačević, T., González-Cataldo, F., Stewart, S. T. & Militzer, B. Miscibility of rock and ice in the interiors of water worlds. Sci. Rep. 12, 13055 (2022).

    Article  ADS  PubMed  PubMed Central  Google Scholar 

  65. Xiao, B. & Stixrude, L. Critical vaporization of MgSiO3. Proc. Natl Acad. Sci. USA 115, 5371–5376 (2018).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  66. Boorstein, W. M. & Pehlke, R. D. Measurement of hydrogen solubility in liquid iron alloys employing a constant volume technique. Metall. Mater. Trans. B 5, 399–405 (1974).

    ADS  CAS  Google Scholar 

  67. Waseda, Y. Interaction parameters in metallic solutions estimated from liquid structure and the heat of solution at infinite dilution. High Temp. Mater. Processes 31, 203–208 (2012).

    Article  ADS  CAS  Google Scholar 

  68. Righter, K., Rowland, R.II, Yang, S. & Humayun, M. Activity coefficients of siderophile elements in Fe–Si liquids at high pressure. Geochem. Persp. Lett. 15, 44–49 (2020).

    Article  Google Scholar 

  69. Hirschmann, M., Withers, A., Ardia, P. & Foley, N. Solubility of molecular hydrogen in silicate melts and consequences for volatile evolution of terrestrial planets. Earth Planet. Sci. Lett.345, 38–48 (2012).

    Article  ADS  Google Scholar 

  70. Okuchi, T. Hydrogen partitioning into molten iron at high pressure: implications for Earth’s core. Science 278, 1781–1784 (1997).

    Article  ADS  CAS  PubMed  Google Scholar 

  71. Moore, G., Vennemann, T. & Carmichael, I. An empirical model for the solubility of H2O in magmas to 3 kilobars. Am. Mineral. 83, 36–42 (1998).

    Article  ADS  CAS  Google Scholar 

  72. Karki, B. B., Wentzcovitch, R. M., de Gironcoli, S. & Baroni, S. Ab initio lattice dynamics of MgSiO3 perovskite at high pressure. Phys. Rev. B 62, 14750–14756 (2000).

    Article  ADS  CAS  Google Scholar 

  73. Katsura, T. et al. Thermal expansion of forsterite at high pressures determined by in situ X-ray diffraction: the adiabatic geotherm in the upper mantle. Phys. Earth Planet. Inter. 174, 86–92 (2009).

    Article  ADS  CAS  Google Scholar 

  74. Shahar, A. & Young, E. D. An assessment of iron isotope fractionation during core formation. Chem. Geol. 554, 119800 (2020).

    Article  ADS  CAS  Google Scholar 

  75. Young, E. D. et al. High-temperature equilibrium isotope fractionation of non-traditional stable isotopes: experiments, theory, and applications. Chem. Geol. 395, 176–195 (2015).

    Article  ADS  CAS  Google Scholar 

  76. Hallis, L. J. et al. Evidence for primordial water in Earth’s deep mantle. Science 350, 795–797 (2015).

    Article  ADS  CAS  PubMed  Google Scholar 

  77. Sossi, P. A., Nebel, O. & Foden, J. Iron isotope systematics in planetary reservoirs. Earth Planet. Sci. Lett. 452, 295–308 (2016).

    Article  ADS  CAS  Google Scholar 

  78. Ni, P. et al. Planet size controls Fe isotope fractionation between mantle and core. Geophys. Res. Lett. 49, e2022GL098451 (2022).

    Article  ADS  CAS  Google Scholar 

  79. Pringle, E. A., Moynier, F., Savage, P. S., Badro, J. & Barrat, J.-A. Silicon isotopes in angrites and volatile loss in planetesimals. Proc. Natl Acad. Sci. USA 111, 17029–17032 (2014).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  80. Savage, P. S. & Moynier, F. Silicon isotopic variation in enstatite meteorites: clues to their origin and Earth-forming material. Earth Planet. Sci. Lett. 361, 487–496 (2013).

    Article  ADS  CAS  Google Scholar 

  81. Geiss, J. & Gloeckler, G. Isotopic composition of H, He and Ne in the protosolar cloud. Space Sci. Rev. 106, 3–18 (2003).

    Article  ADS  CAS  Google Scholar 

  82. Altwegg, K. et al. 67P/Churyumov–Gerasimenko, a Jupiter family comet with a high D/H ratio. Science 347, 1261952 (2015).

    Article  CAS  PubMed  Google Scholar 

  83. Bockelée-Morvan, D. et al. Herschel measurements of the D/H and 16O/18O ratios in water in the Oort-cloud comet C/2009P1 (Garradd). Astron. Astrophys. 544, L15 (2012).

    Article  ADS  Google Scholar 

  84. Alexander, C. M. O. et al. The provenances of asteroids, and their contributions to the volatile inventories of the terrestrial planets. Science 337, 721–723 (2012).

    Article  ADS  CAS  PubMed  Google Scholar 

  85. Waite Jr, J. H. et al. Liquid water on Enceladus from observations of ammonia and 40Ar in the plume. Nature 460, 487–490 (2009).

    Article  ADS  Google Scholar 

  86. Gough, D. O. Solar interior structure and luminosity variations. Solar Phys. 74, 21–34 (1981).

    Article  ADS  CAS  Google Scholar 

  87. Genda, H. & Ikoma, M. Origin of the ocean on the Earth: early evolution of water D/H in a hydrogen-rich atmosphere. Icarus 194, 42–52 (2008).

    Article  ADS  CAS  Google Scholar 

  88. Lammer, H. et al. Origin and loss of nebula-captured hydrogen envelopes from ‘sub’- to ‘super-Earths’ in the habitable zone of Sun-like stars. Mon. Not. R. Astron. Soc. 439, 3225–3238 (2014).

  89. Yang, L., Ciesla, F. J. & Alexander, C. M. The D/H ratio of water in the solar nebula during its formation and evolution. Icarus 226, 256–267 (2013).

    Article  ADS  CAS  Google Scholar 

  90. Holton, J. R. On the global exchange of mass between the stratosphere and troposphere. J. Atmos. Sci. 47, 392–395 (1990).

    Article  ADS  Google Scholar 

  91. Pahlevan, K., Schaefer, L. & Hirschmann, M. M. Hydrogen isotopic evidence for early oxidation of silicate Earth. Earth Planet. Sci. Lett. 526, 115770 (2019).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  92. Krasnopolsky, V. A., Mumma, M. J. & Gladstone, G. R. Detection of atomic deuterium in the upper atmosphere of Mars. Science 280, 1576–1580 (1998).

    Article  ADS  CAS  PubMed  Google Scholar 

  93. Young, E., Yeung, L. & Kohl, I. On the Δ17O budget of atmospheric O2. Geochim. Cosmochim. Acta 135, 102–125 (2014).

    Article  ADS  CAS  Google Scholar 

  94. Yeung, L. Y. et al. Extreme enrichment in atmospheric 15N15N. Sci. Adv. 3, eaao6741 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  95. Barnes, J. J. et al. The origin of water in the primitive Moon as revealed by the lunar highlands samples. Earth Planet. Sci. Lett. 390, 244–252 (2014).

    Article  ADS  CAS  Google Scholar 

  96. Lellouch, E. et al. The deuterium abundance in Jupiter And Saturn from ISO-SWS observations. Astron. Astrophys. 670, 610–622 (2001).

    Article  ADS  Google Scholar 

  97. Feuchtgruber, H. et al. The D/H ratio in the atmospheres of Uranus and Neptune from Herschel-PACS observations. Astron. Astrophys. 551, A126 (2013).

    Article  Google Scholar 

Download references

Acknowledgements

This AEThER publication is funded in part by the Alfred P. Sloan Foundation under grant G202114194. H.E.S. gratefully acknowledges NASA grant 80NSSC18K0828 for financial support during preparation and submission of the work.

Author information

Authors and Affiliations

Authors

Contributions

All authors contributed significantly to the formal analysis. E.D.Y. led the writing of the paper aided by A.S. and H.E.S.

Corresponding author

Correspondence to Edward D. Young.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature thanks David Catling and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Plot of surface temperatures that allow for a gravitationally bound primary H2 atmosphere versus mass of planetary embryos19.

The region in temperature-mass space where a primary atmosphere is possible is shaded. The approximate solidus for silicate melt is overlain as the horizontal line.

Extended Data Fig. 2 Summary of equilibrium calculations for Si in metal in embryos with masses of 0.5M as a function of metal–silicate equilibration temperature (Tcore–mantle) and mass fraction of initial primary H2-rich atmosphere relative to the planet.

Arrow illustrates values for models that satisfy the required density deficit in the core but where H is scarce or absent.

Extended Data Fig. 3 Pressure vs. radius for 0.3M (left) and 0.5M (right) embryos.

Breaks in slope mark the core–mantle boundaries.

Extended Data Fig. 4 Iron isotope ratios of bulk silicate for model embryos compared with recent estimates for bulk Earth (grey bar) and chondrites showing that the model reproduces the offset between initial materials (chondrites, δ57Fe = 0) and Earth.

Black filled symbols are for E chondrites while white symbols are for all other chondrite groups. The multi-colour contours are probability densities for the chondrite δ57Fe values with an average indistinguishable from δ57Fe = 0.0. The y axis values are assigned randomly to each datum in equal spacings for clarity, with E chondrites confined to the lower quarter of the ordinate.

Extended Data Fig. 5 Summary of D/H ratios for Solar System materials from a variety of literature sources.

The circle + symbol labelled E denotes bulk Earth76. Black/white symbol labelled M refers to lunar highland apatites95. Blue symbols refer to calculated values for original water based on measured asteroidal rock values84. U, N, J, and S refer to Uranus, Neptune, Jupiter, and Saturn, respectively96,97. Model values for Earth’s water, primordial hydrogen atmosphere, and metal described here are indicated within the grey box, where the model is assigned the terrestrial value.

Supplementary information

Supplementary Tables

This file contains Supplementary Tables 1–4.

Peer Review File

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Young, E.D., Shahar, A. & Schlichting, H.E. Earth shaped by primordial H2 atmospheres. Nature 616, 306–311 (2023). https://doi.org/10.1038/s41586-023-05823-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-023-05823-0

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing