Ocean planets are not uncommon in our galaxy. Because these distant celestial objects are completely covered by water, they can be a real warehouse of life. Did you know, however, that the Earth was also covered by a huge ocean 3.2 billion years ago and had no continents at all? According to an article published on lifescience.com, the known continents appeared much later than we previously thought. So what influenced the development of the blue planet and made it a place where there are not only oceans but also land?
The earth was an ocean planet
When a series of strong collisions between dust and space rocks marked the birth of our planet 4.5 billion years ago, the very young earth was a bubbling, molten magma ball that was thousands of kilometers deep. As the rotma gradually cools several million years after its birth, it forms the first mineral crystals in the earth's crust. After 4 billion years, they were discovered by scientists from northwest Australia who decided to analyze the race found in the depths of the smallest continent on the planet. During the course of the study, the crystals were found to be the remains of an ancient seabed, indicating that there was once no land on Earth in the way we are all used to.
See also: The closest Exoplanet to Earth can be "densely populated".
According to the theory put forward by scientists, the continents appeared much later: the moment when plate tectonics pushed up the huge rocky land masses to break through the sea surface. In the meantime, Earth's first water may have been brought here from ice-rich comets from outside our solar system. An alternative version claims that moisture in the form of dust could come from a cloud of particles that created the sun and rotating objects around it.
When the earth was a hot ocean of magma, water vapor and gases escaped from the surface of a hot ball into its atmosphere. "Then heavy rain fell from the earth's gas envelope, caused by a great cooling," said lead author Benjamin Johnson, associate professor at the Department of Geological and Atmospheric Sciences at Iowa State University.
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In their new study, Johnson and his colleague Boswell Wing, associate professor of geological sciences at the University of Colorado, turned to a unique find they had made in the Australian outback. The material they discovered is a rocky structure that covered the ocean floor 3.2 billion years ago. A piece of rock has received oxygen isotopes, which researchers can use to detect changes in the temperatures of the planet's ancient ocean and its global climate.
After analyzing more than 100 samples of sedimentary rocks, the scientists found that about 3.2 billion years ago the oceans contained more oxygen-18 than oxygen-16, which is currently the most common in the ocean. By leaching out oxygen-18 from the oceans, the country's landmasses indicate that there were simply no continents in ancient times. In this case, could a life have arisen under conditions that are different from those of modernity?
Benjamin Johnson and his colleague tend to believe that life on Earth can only occur in two places: hydrothermal vents and ponds on land. Both these and others are able to provide gradually developing organisms with enough organic substances for growth and development. However, if the theory of the scientist is confirmed, it will only be possible to find life on human ocean planets like GJ 1214b or Kepler-22b if the above exoplanets follow the path our blue once passed. Planet. Otherwise, water can be important, but only an ingredient for the creation of life on an organic basis, which without the inclusion of additional factors cannot provide a comfortable environment for the formation of the first microorganisms.