Rosa Rubicondior: Refuting Creationism - How Earth Was Really Made

Thursday, 18 September 2025

Refuting Creationism - How Earth Was Really Made - No God-Magic Needed

High-energy Venus Impacts

An SwRI-led team compared the early impact history of Venus and Earth, determining that Venus experienced higher-energy impacts that created a superheated core. Models show these conditions could create Venus’ extended volcanism and younger surface.

Evolution of Terrestrial Planets
A new SwRI-led paper highlights the scientific progress made in understanding the evolution of terrestrial planets, including the effects of late large impacts on pre-existing modes of tectonics. For instance, the Earth experienced transient subduction, when one tectonic plate slides beneath another. Because Venus’ surface is covered by a single plate, a high-velocity impact led to a superheated core and long-lived volcanism. On Mars, a large, low-velocity impact facilitated variations in its hemispheres. Impacts also modify the atmospheres of terrestrial planets in profound ways, including eliminating or supplementing existing gases.

SwRI-led paper summarizes notable progress in understanding the evolution of the terrestrial planets | Southwest Research Institute

Creationist myths describe Earth as a flat world under a dome at the centre of the Universe, made just a few thousand years ago. The real story is far more extraordinary: a fragile chain of chance events and natural forces that made life possible on this small rocky planet.

Earth orbits an ordinary star on the edge of the Milky Way, one of billions in one of trillions of galaxies. That it exists at all is down to gravity, physics, and luck. Out of this came a beautiful world teeming with life—including one species able to marvel at the Universe and ask how it all began, and in it's fearful, ignorant infancy, make up the myths to explain it that now pass for science in some scientifically backward cultures.

One early collision with a smaller planetoid gave us the Moon, tides, and seasons; this or a later impact may, according to this study, be responsible for tectonic plates, giving us a forever changing, dynamic planet, driving evolutionary divergence. While not required for life to appear, these events shaped the planet into the diverse, life-rich world we know today.

Background^ The Making of Earth.

Earth formed about 4.5 billion years ago from the protoplanetary disc around the young Sun.

Early growth was driven by accretion—smaller bodies colliding and merging under gravity.

A giant impact with a Mars-sized body, often called Theia, likely created the Moon and gave Earth its axial tilt.

The young Earth endured intense bombardment during the Late Heavy Bombardment, which may have delivered water and key volatiles.

Life emerged within the first billion years, evolving alongside a planet still settling into stability.

Did You Know?

The Sun is just one of ~200 billion stars in the Milky Way.

Our galaxy is one of trillions in the observable Universe.

Earth is the only known planet where life has evolved to ask how it all began.

The odds of Earth’s precise conditions—liquid water, stable climate, a protective Moon—are a remarkable outcome of chance and physics.

Key Terms

Accretion: The gradual build-up of planets from smaller bodies.

Planetesimal: A small, early planetary body formed from dust and rock.

Theia: The hypothesised Mars-sized body that collided with Earth.

Late Heavy Bombardment: A period of frequent, large impacts about 4.1–3.8 billion years ago.

Exoplanet: A planet orbiting a star outside our Solar System.

Now, Dr Simone Marchi of the Southwest Research Institute and Jun Korenaga of Yale have reconstructed the final 1% of Earth’s growth. Their work is published in Nature and outlined in a SwRI press release.

SwRI-led paper summarizes notable progress in understanding the evolution of the terrestrial planets
Southwest Research Institute collaborated with Yale University to summarize the scientific community’s notable progress advancing the understanding of the formation and evolution of the inner rocky planets, the so-called terrestrial planets. Their Nature Review journal paper focuses on late accretion’s role in the long-term evolution of terrestrial planets, including their distinct geophysical and chemical properties as well as their potential habitability.
Solar systems form when clouds of gas and dust begin to coalesce. Gravity pulls these elements together, forming a central star, like our Sun, surrounded by a flattened disk of consolidating materials. Our terrestrial planets — Mercury, Venus, Earth and Mars — formed as smaller rocky objects accumulated, or accreted, into larger planetesimals and eventually protoplanets, when late impacts made critical contributions. The Earth was probably the last terrestrial planet to form, reaching about 99% of its final mass within about 60–100 million years after the first solids began to consolidate.

We examined the disproportionate role late accretion — the final 1% of planetary growth — plays in controlling the long-term evolution of the Earth and other terrestrial planets. Differences in planets’ late accretions may provide a rationale for interpreting their distinct properties. We made advances constraining the history of late accretions, using large-scale impact simulations and understanding the consequences of interior, crustal and atmospheric evolution.

Dr. Simone Marchi, first author.
Southwest Research Institute
Boulder, CO, USA.

A recent wealth of geochemical data from meteorites and terrestrial rocks has led to a better understanding of the formation of planets. With these advances, collisions and their various consequences have emerged as crucial processes affecting the long-term evolution of terrestrial planets. For instance, the tectonics, atmospheric composition and water of Venus and Earth appear to be tied to late accretion. The surface variability of Mars and the high metal-to-silicate mass ratio of Mercury are also associated with late large impacts.
Impact histories should play a critical role in the search for habitable exoplanets like Earth. The habitability of a rocky planet depends on the nature of its atmosphere, which is tied to plate tectonics and mantle outgassing. The search for Earth’s twin might focus on rocky planets with similar bulk properties — mass, radius and habitable zone location — as well as a comparable collision history.

Dr. Simone Marchi.

Models provide insights into the total number and history of impacts, but geologic activity can obscure some evidence. The scientific community uses lunar impacts, additional observations and dynamic models to better understand and “constrain” the bombardment history of the rocky planets.

The fate of an impactor’s material is crucial to understanding the target body’s physical and chemical evolution. We assess the abundance of certain elements that have an affinity for metal in the mantle and crust of planetary objects to understand the timing and processes that led to the formations of their core, mantle and crust.

Dr. Simone Marchi.

Impacts also modify the atmospheres of terrestrial planets in profound ways, particularly affecting the abundance of volatile elements, such as water and carbon, that easily vaporize. Collisions can blow off pre-existing atmospheres, or conversely, volatile-rich impactors can deliver these components to a planet’s surface and atmosphere. The abundance of volatiles provides insights into the formation, evolution and habitability of terrestrial planets.

These processes almost certainly played a role in the prebiotic chemistry of early Earth, but their implications in the origin of life remain a mystery

Dr. Simone Marchi.

Publication:
Marchi, S., Korenaga, J.
The shaping of terrestrial planets by late accretions.
Nature 641, 1111–1120 (2025). https://doi.org/10.1038/s41586-025-08970-8

The shaping of terrestrial planets by late accretions
Simone Marchi & Jun Korenaga

Abstract
Terrestrial planets—Mercury, Venus, Earth and Mars—formed by the accretion of smaller objects. The Earth was probably the latest terrestrial planet to form and reached about 99% of its final mass within about 60–100 Myr after condensation of the first solids in the Solar System. This Review examines the disproportionate role of the last approximately 1% of planetary growth, or late accretion, in controlling the long-term evolution of the Earth and other terrestrial planets. Late accretion may have been responsible for shaping Earth’s distinctive geophysical and chemical properties and generating pathways conducive to prebiotic chemistry. Differences in the late accretion of a planet may provide a rationale for interpreting the distinct properties of Venus and Earth (for example, tectonism, atmospheric composition, water content), the surface dichotomy of Mars and the high core-to-silicate mass ratio of Mercury. Large collisions and ensuing processes are likely to occur and modulate the evolution of rocky exoplanets as well, and they should be considered in our quest to find Earth-like worlds.

Marchi, S., Korenaga, J.
The shaping of terrestrial planets by late accretions.
Nature 641, 1111–1120 (2025). https://doi.org/10.1038/s41586-025-08970-8

© 2025 Springer Nature Ltd.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.

The picture painted by modern science could hardly be further removed from the simple story told in Genesis. Far from being created fully formed in a matter of days, Earth is the outcome of billions of years of natural processes—violent impacts, cosmic chance, and the slow interplay of gravity, chemistry, and time.

Rather than being placed at the centre of creation, our planet is one among countless worlds, orbiting an ordinary star on the edge of a vast galaxy. Its history is written not in sacred texts but in rocks, craters, isotopes, and the very elements that make up our bodies.

For those who cling to a literal reading of the Bible, this story may feel humbling. Yet, for those who embrace it, the scientific account is far richer and more inspiring. It shows us a Universe where life is not handed down by decree but emerges from natural laws that operate everywhere. The fragility—and improbability—of our existence makes it all the more precious.

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