Results tagged “Early Earth”

Earth's Ancient Barometric Pressure

Researchers supported in part by the NASA Astrobiology Program have attempted to better understand global barometric pressure on Earth during the Archaean by studying vesicle sizes in 2.9 billion year-old lavas that erupted near sea level.

Chemical changes in the oceans more than 800 million years ago almost destroyed the oxygen-rich atmosphere that paved the way for complex life on Earth, new research suggests.

Oxygen in the form of the oxygen molecule (O2), produced by plants and vital for animals, is thankfully abundant in Earth's atmosphere and oceans. Researchers studying the history of O2 on Earth, however, know that it was relatively scarce for much of our planet's 4.6 billion-year existence.

During accretion, the young rocky planets are so hot that they become endowed with a magma ocean. From that moment, the mantle convective thermal flux control the cooling of the planet and an atmosphere is created by outgassing.

Sleuthing by a Rice University postdoctoral fellow is part of a new Nature paper that gives credence to theories about Earth's atmosphere 1.4 billion years ago.

Earth's oxygen levels rose and fell more than once hundreds of millions of years before the planetwide success of the Great Oxidation Event about 2.4 billion years ago, new research from the University of Washington shows.

Oxygen isotopes in marine cherts have been used to infer hot oceans during the Archean with temperatures between 60 deg C (333 K) and 80 deg C (353 K). Such climates are challenging for the early Earth warmed by the faint young Sun.

Conditions on Earth for the first 500 million years after it formed may have been surprisingly similar to the present day, complete with oceans, continents and active crustal plates.

Understanding the atmosphere's composition during the Archean eon is a fundamental issue to unravel ancient environmental conditions.

During the Archean eon, between about 3.8 billion years ago and 2.5 billion years ago, the Sun was about 20 to 25 percent fainter than it is today. With less sunlight to warm the Earth, the oceans should have been frozen over, but geological evidence suggests that this was not the case.

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