Scientists propose a new theory: Comet impacts could have originated Earth's vast oceanic expanse.
Where do our planet's oceans originate from? The discussion on whether water might have initially been delivered to Earth by comets colliding with its surface has resurfaced following a recent groundbreaking study.
Announced this month in Science Advances, a study by NASA-led researchers examines a comet called 67P/Churyumov-Gerasimenko, which was studied by the European Space Agency's Rosetta mission in 2014. This mission marked the first time a comet was ever rendezvoused with and a lander was deployed to one.
Water Source
The research indicates that 67P's water might share characteristics with Earth's oceans, making comets a feasible water source for our planet. This finding challenges prior conclusions and bolsters the notion that Jupiter-family comets—short-period comets that orbit the sun within 20 years—may have played a vital role in delivering water to early Earth. The new statistical research contradicts an earlier finding from 2014, which dismissed the connection.
Missing Link
Determining the origins of Earth's water is crucial to comprehending how life developed and why it was absent on other planets in our solar system. Approximately 71% of Earth's surface is covered in oceans, containing 97% of Earth's water. Understanding its source represents a missing link in scientists' understanding of our planet's hydrological history.
‘Dark Comets’
In July, a study proposed that "dark comets" — a new category of cometary bodies with low albedo due to dark surfaces — might have significantly contributed to Earth's oceans through impacts during its formative years. According to the authors, these comets, originating from the solar system's outer regions, could have played a role in forming the Earth's oceans.
Comets or Asteroids?
A paper published in June 2023 suggested that water-rich asteroids from the outer regions of the asteroid belt delivered substantial amounts of water to Earth. The researchers discovered that the water in carbonaceous chondrite meteorites bears a resemblance to the water in Earth's oceans. Additionally, hydrated minerals were identified on asteroids like Itokawa and Ryugu, samples of which were retrieved by the Hayabusa and Hayabusa 2 missions.
Interstellar Origin
The theory that comets and asteroids primarily delivered Earth's water after its formation is still under debate. Research published in March 2023 indicates that Earth's water may have existed before the sun was formed. Scientists discovered at least 1,200 times the amount of water in all of Earth's oceans around a protostar — a young star in its early stages of development — 1,305 light-years distant in the constellation Orion. This discovery of ancient interstellar ice around a young star suggests that a considerable portion of Earth's water originated from interstellar space—and implies that water may be more prevalent in planetary systems than previously thought, potentially increasing the likelihood of life elsewhere in the universe.
Wishing you clear skies and wide eyes.
- The study on comet 67P, conducted by NASA-led researchers and published in Science Advances this month, suggests that its water may share similarities with Earth's oceans, making comets a potential water source for our planet.
- The groundbreaking study on 67P collaborates with the idea that Jupiter-family comets, which are short-period comets that orbit the sun within 20 years, might have played a significant role in delivering water to early Earth.
- The Rosetta mission, conducted by the European Space Agency in 2014, was the first to rendezvous with a comet and deploy a lander, providing valuable data for scientists studying the origins of Earth's oceans.
- A recent study proposes that "dark comets," or cometary bodies with low albedo due to dark surfaces, may have contributed to Earth's oceans through impacts during its formative years, originating from the solar system's outer regions.
- The ongoing debate in planetary science surrounds the origins of Earth's water, with theories suggesting that comets, asteroids, or even interstellar space played a primary role in delivering water to our planet shortly after its formation.