Professor of geology at Curtin University in Australia is Chris Kirkland. Astrophysics senior lecturer Phil Sutton teaches at the University of Lincoln in the UK. A new paper on Earth’s journey across the cosmos as a member of the solar system was written by the experts.

The opening line of William Blake’s poem, “To see a world in a grain of sand,” is an often used expression that also sums up some of what geologists do.

We can see the makeup of mineral grains that are hardly bigger than a human hair. We next extend the chemical processes they point to in order to consider how our planet was created.

Looking out to the universe

Chris Kirkland is a senior geochronologist of the Geological Survey of Western Australia and a professor of geology at Curtin University in western Australia. He oversees the Curtin Node of the Centre for Exploration’s Timescales of Mineral Systems Theme.

Astrophysicists aim to comprehend the cosmos and our position in it on a far grander scale. They create models that describe the celestial objects’ orbits using physical rules.

Even if we may believe that Earth’s surface was fully created by internal processes, our planet has surely experienced the influence of its cosmic surroundings. Included in this are cyclical modifications to the Earth’s orbit, fluctuations in the sun’s output, gamma ray bursts, and of course meteorite strikes.

Given that the Earth is more than 80 times more massive than its grey satellite, just gazing at the Moon and its cratered surface should serve as a reminder of this. In reality, new research has shown the significance of meteorite impacts in the formation of the Earth’s continental crust, contributing to the formation of buoyant “seeds” that floated on the planet’s outermost layer during its early years.

We have now discovered a rhythm in the formation of this early continental crust with the help of our multinational team of colleagues, and the pace suggests an incredibly powerful driving force. The journal Geology just just published this paper.

Residing inside the Milky Way galaxy makes it impossible to picture, but our galaxy is thought to be similar to other barred spiral galaxies, like NGC 4394. (Image credit: ESA/Hubble & NASA)

The rhythm of crust production on Earth

At the University of Lincoln in Lincoln, England, where he holds a senior lectureship in astrophysics, Phil Sutton conducts research on the solar system’s planets, moons, asteroids, and planetary rings.

On Earth, molten or semi-molten magma is the source of many rocks. The mantle, which is a mostly solid but slowly moving layer under the planet’s crust, or even older fragments of pre-existing crust can be heated to produce this magma. Magma that was once liquid gradually solidifies into rock when it cools.

Mineral grains expand as a result of the cooling and crystallization of magma, which can trap elements like uranium that decay over time and act as a kind of age-recording timer. Additionally, crystals can hold onto other substances that, as a surname would, trace a person’s family, monitor the composition of their parental magma.

We may then create a chronology of crust creation using these two pieces of knowledge: age and composition. Then, by employing the Fourier transform’s mathematical prowess, we can decipher its fundamental frequencies. Similar to decoding cake batter ingredients that have been blended, this technology essentially decodes the frequency of events.

Our results from this approach suggest an approximate 200-million-year rhythm to crust production on the early Earth.

Our place in the cosmos

However, another procedure has a comparable rhythm. While the four spiral arms of the Milky Way and our solar system are both rotating around the supermassive black hole at the galaxy’s center, their rates of rotation are different.

Our solar system is surging into and out of the spiral arms of the galaxy because the spiral arms revolve at 210 km/s while the sun travels at 240 km/s. The spiral arms can be compared as thick regions that delay the movement of stars, similar to a traffic bottleneck that only dissipates further out (or through the arm).

According to this model, our solar system enters spiral arms of the galaxy once every 200 million years.

Therefore, it appears that the timing of crust formation on Earth and the amount of time it takes to orbit the galactic spiral arms may be related, but why?

Strikes from the cloud

The Oort cloud, a collection of cold, rocky debris, is assumed to circle our sun at the furthest reaches of our solar system.

The Oort cloud is thought to interact with the Solar System as it periodically moves into a spiral arm, moving material from the cloud closer to the inner Solar System. Even Earth may be struck by some of this stuff.

The asteroid belt’s stony rocks strike Earth on a fairly regular basis, traveling at an average speed of 15 km/s. The average speed of a comet leaving the Oort cloud is 52 km/s, however.

We contend that the record of crust production found in microscopic mineral grains is indicative of these repeated high-energy impacts. Large areas of the Earth’s surface are excavated by comet impacts, which causes the mantle to melt due to decompression, just unlike when you pop the cork on a bottle of champagne.

This molten rock essentially floats atop the denser mantle because it is rich in light elements like silicon, aluminum, sodium, and potassium. Although there are numerous different methods to create continental crust, it is most likely that the buoyant seeds of crust were created by impacts on our early planet. Later geological processes’ magma would stick to those early seeds.

The majority of Earth’s natural cycles depend on the continental crust because it interacts with water and oxygen to create new weathering products, holds the majority of metals, and contains biological carbon.

Cataclysmic occurrences like large meteorite strikes have the potential to wipe out all life. However, impacts could have played a crucial role in the formation of the continental crust on which we now stand.

Some have even suggested that interstellar asteroids transported life throughout the universe due to their recent transit through the Solar System.

Regardless of how we got here, standing on a beautiful night and gazing up at the stars and the patterns they leave in the sky while feeling the mineral grains, rock, and continental crust below you are both awe-inspiring experiences connected by a very big rhythm.