The earliest history of the Solar System is inscribed in meteorites and the present-day structure of the inner terrestrial and outer gaseous and ice-rich planet population. We developed a new theory that explains our own home planetary system as the result of formation in two distinct episodes. This sets the inner and outer planets on divergent evolutionary paths already during the accretion of the proto-Sun and reinterprets the origins of the Earth’s earliest atmosphere and oceans.

This blog article summarises the research published in Lichtenberg et al., Science (2021), openly accessible at arXiv:2101.08571.

The Solar System has two quite different parts: the inner Solar System features small planets — Mercury, Venus, Earth, and Mars — that are all relatively dry, with little water. Even though the vast surface oceans make the Earth appear to be an ‘ocean world’, water makes up only about 0.1 per cent by mass of the whole planet. The outer Solar System on the other hand appears much more water- and volatile-rich, with much bigger and wetter planets — Jupiter, Saturn, Uranus…

Our own world started out as a literal hell — at the onset of the ‘Hadean’ eon the Moon-forming impact melted and vaporized large parts of the adolescent Earth. The resulting ‘magma ocean’ cooled down over a few million years, eventually allowing the water vapor in the atmosphere to rain out and form the earliest oceans not too long after the last giant collision — or so the story goes, according to the combined picture from geochemical, astronomical, and planetary science studies. But does this story hold equally well for other planets, such as Venus, Mars, or even rocky planets in other, extrasolar planetary systems?

This blog article summarises the research published in Lichtenberg et al., Journal of Geophysical Research: Planets (2021), openly accessible at arXiv:2101.10991.

The question of how this magma ocean epoch evolves is of foremost importance for better understanding the planetary surface conditions on young rocky planets, and in turn our own origins. Latest estimates for the emergence of the earliest life on Earth push the timeline further and further back toward the formation of the planet itself. We have evidence for liquid water on the surface as early as ~4.4 billion years ago (the Solar System formed ~4.567 billion years ago)…

This is a repost of an original contribution to Nature Research Astronomy Community, discussing the research project published as Lichtenberg et al., Nature Astronomy Letters (2019). A free-to-read link to the publication can be found here.

Water seems to be abundant on Earth and covers more than two thirds of the surface of our world. But in astronomical terms the inner terrestrial planets appear very dry. Compared to the relative fraction in the solar system’s gas and ice giants, they lack their ‘fair share’ of volatiles compared to the Sun. Aside from the absence of land, acquired water mass fractions…

This is a plain text narrative of the research project ‘Magma ascent in planetesimals: control by grain size’, published as Lichtenberg et al., Earth and Planetary Science Letters (2019), openly accessible at arXiv:1802:02157.

The inner life of rocky planets’ seeds

The terrestrial worlds of the solar system were born out of growing swarms of so-called planetesimals. These bodies were probably similar to the current-day asteroids, which lurk in the no man’s land between Mars and Jupiter. However, unlike the cold and inactive asteroids, planetesimals are thought to have had a geologically active interior owing to internal heating from the radioactive decay of short-lived radionuclides. The temperatures inside…

This blog article is a plain text summary of the research efforts published in Icarus, openly accessible at arXiv:1711.02103.

What are chondrules, and why should I care?

The early Solar system was very likely an uncomfortable place. The young Sun was surrounded by a ring of gas and dust, the protoplanetary disk in which the planets were forming. In the inner part, close to the Sun, it was extremely hot, potentially a few thousand Kelvin, and outside, beyond the current orbit of Jupiter, the temperatures were freezing cold, at only a few dozen Kelvin. In the midplane of the disk, myriads of planetesimals (small asteroid-like rocky bodies in…

Tim Lichtenberg

Postdoctoral Fellow @ Atmospheric, Oceanic and Planetary Physics, University of Oxford.

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