A new study reveals that life on Earth not only has cosmic origins but may also stem from a catastrophic event.
According to Space.com, a research team from ETH Zurich (Switzerland), the University of Cambridge, the University of Oxford, The Open University (UK), and the University of Bergen (Norway) investigated whether fine cosmic dust could provide answers about the origins of life on Earth.
Ancient cosmic dust, originating from catastrophic events, may have seeded life on ancient Earth – (Illustration by AI: Anh Thu).
The origins of life on Earth have long remained a mystery. The most widely accepted hypothesis lately suggests that the first seeds of life came from space, after studies indicated that Earth’s rocky materials alone were insufficient to spontaneously generate life.
However, it is still unclear how this life arrived on Earth and how it managed to survive the tumultuous journey.
The new study concludes that cosmic dust is the most viable candidate.
In an article published in the journal Nature Astronomy, the authors noted that streams of cosmic dust reaching Earth are essentially constant on an annual timescale, unlike larger objects that are more erratic.
Moreover, some cosmic dust particles pass through Earth’s atmosphere relatively gently, thus preserving a larger proportion of primitive elements compared to larger colliding bodies.
Although this distribution mechanism is reasonable, this material is rarely considered in prebiotic theories because it spreads over a vast area, possibly making it less noticeable or more difficult to study at sufficiently high concentrations.
Using astrophysical simulations and geological models, the research team sought to quantify the flux and composition of cosmic dust that may have accumulated on Earth’s surface during the first 500 million years following the Moon-forming event, which was also when Earth stabilized in terms of materials.
This event is believed to have originated from the collision of a Mars-sized planet, Theia, with primordial Earth, mixing materials and leading to the separation of Earth and the Moon as we know them today.
Such collisions were common during the formation of the Solar System, so during this early period, Earth could have been bathed in dust at levels 100 to 10,000 times higher than today.
Fortunately, many of these dust particles originated from collisions of celestial bodies containing the essential seeds for life. They found their promised land to create the rich world we know today.
Additionally, the team’s model also indicates potential locations where traces of ancient cosmic dust could be found.
First, there are deep-sea sediments, although they are quite scarce and difficult to locate.
More feasibly, there are desert and glacial areas, where this cosmic material may account for over 50% of the sediments. The highest concentrations, exceeding 80%, will be found in areas where glaciers are melting.
These will be identified within structures known as cryoconite holes in these frigid regions, which are holes on the glacier surface formed when wind carries sediment onto the glacier.
Antarctic-like icebergs containing cryoconite sediments rich in cosmic dust, along with proglacial lakes, appear to provide an excellent environment to support the early stages of life.
