Titan: Atmosphere Originates


The imprints of raindrops preserved in 2.7bn-year-old rock are being used to figure out what the atmosphere was like on the early Earth. Scientists have used the depressions drops left to calculate how fast they were going as they impacted the ground. This has allowed them to determine the density of air in ancient times. 

This “palaeobarometry” approach, revealed at the AGU Fall Meeting, will help constrain the models that try to simulate conditions in Archaean times.

Earth 2.7 billion years ago was very different from the planet we know today.It spun much faster, the Moon was closer and the Sun was much weaker. And there were no animals or plants in existence back then; the air was simply not breathable.

“There was probably quite a bit of nitrogen in the atmosphere, like today, but there was no oxygen,” explained Sanjoy Som from Nasa’s Ames Research Center.

“The oxygen was likely replaced by greenhouse gases such as carbon dioxide and methane." http://www.bbc.co.uk

“It spun much faster, the Moon was closer and the Sun was much weaker. And there were no animals or plants in existence back then; the air was simply not breathable.”

Or spun about 16x slower, once was a “moon” and much father away from the Sun…

“There was probably quite a bit of nitrogen in the atmosphere, like today, but there was no oxygen,” 

“Similarly to Earth, Titan’s atmosphere is mostly nitrogen but there is also methane and many other organic compounds.”ESA





PASADENA, Calif. — "As spring continues to unfold at Saturn, April showers on the planet’s largest moon, Titan, have brought methane rain to its equatorial deserts, as revealed in images captured by NASA’s Cassini spacecraft. This is the first time scientists have obtained current evidence of rain soaking Titan’s surface at low latitudes. Extensive rain from large cloud systems, spotted by Cassini’s cameras in late 2010, has apparently darkened the surface of the moon. The best explanation is these areas remained wet after methane rainstorms." NASA.gov




The Great Oxygenation Event

“Great Oxidation, was the biologically induced appearance of free oxygen (O2) in Earth’s atmosphere. This major environmental change happened around 2.4 billion years ago.”

O2 build-up in the Earth’s atmosphere. Red and green lines represent the range of the estimates while time is measured in billions of years ago (Ga).
Stage 1 (3.85–2.45 Ga): Practically no O2 in the atmosphere.
Stage 2 (2.45–1.85 Ga): O2 produced, but absorbed in oceans & seabed rock.
Stage 3 (1.85–0.85 Ga): O2 starts to gas out of the oceans, but is absorbed by land surfaces.
Stages 4 & 5 (0.85–present): O2 sinks filled and the gas accumulates.


Great Oxidation Event [2.4 billion years ago] = Beginning of Titan



“Large amounts of oxygen released by ocean plankton made Earth’s atmosphere breathable for the first time in history. This happened about 500 million years ago.”

“When the first simple organisms appeared in the oceans more than 3.5 billion years ago, the atmosphere was mostly nitrogen, hydrogen, water vapor, and carbon dioxide. Some scientists speculate that these organisms were similar to microbes found in hydrothermal vents, which derive their energy via chemosynthesis from gases like methane and hydrogen sulfide spewed from the vents.

Not long after, possibly about 3 billion years ago, the first photosynthetic organisms had evolved and begun releasing oxygen, much of it used up in geological processes. The rest started to slowly accumulate in the atmosphere.”

“Things started to get interesting during a geologic period known as the Cambrian period, from 542 to 488 million years ago. An event notable in the history of life on Earth, called the Cambrian Explosion, occurred during this time. It was a burst in diversity of animal life in shallow seas that started 540 million years ago and lasted for about 40 million years. This milestone in evolution produced almost all the lineages of animals alive today. It’s believed that life had not yet evolved to colonize land during the Cambrian Explosion.”


Simple Organisms [3.5 billion years ago] = Europa
Breathable Atmosphere [500 million years ago] = End of Mars, Beginning of Earth



Evolution of Oxygen — Long-Standing Theory Challenged

“A team led by geochemists at the University of California, Riverside challenges the so-called Great Oxidation Event 2.4 billion years ago, and the simple notion of an up-only trend for early oxygen and provides the first compelling direct evidence for a major drop in oxygen after the first rise. The Great Oxidation was critical for the origin and evolution of the first forms of eukaryotic life. The second big step in the up-only hypothesis occurred almost two billion years later, coinciding with the first appearances and earliest diversification of animals.

“Our group is among a subset of scientists who imagine that oxygen, once it began to accumulate in the ocean-atmosphere system, may have ultimately risen to very high levels about 2.3-2.2 billion years ago, perhaps even to concentrations close to what we see today,” said Timothy Lyons, a professor of biogeochemistry and the principal investigator of the project. “But unlike the posited irreversible rise favored by many, our new data point convincingly to an equally impressive, and still not well understood, fall in oxygen about 200 million years later.”

This drop in oxygen may have ushered in more than a billion years that were marked by a return to low-oxygen concentrations at Earth’s surface, including the likelihood of an oxygen-free deep ocean. “It is this condition that may have set the environmental stage and ultimately the clock for the advance of eukaryotic organisms and eventually animals,” he said. Study results appear online this week in the Proceedings of the National Academy of Sciences.

“The time window between 2.3 and 2.1 billion years ago is famous for the largest and longest-lived positive carbon isotope excursion in Earth history,” said Noah Planavsky, currently a postdoctoral fellow at Caltech, and first author of the research paper. He explained that carbon isotopes are fractionated during photosynthesis. When organic matter is buried, oxygen is released and rises in the biosphere. The burial of organic matter is tracked by the positive or heavy isotopic composition of carbon in the ocean.”

University of California – Riverside


The drop after the first major rise in oxygen levels [2.3-2.1 billion years ago] is evident of Titan’s transition to Triton



“Triton’s thin atmosphere is composed mainly of nitrogen with small amounts of methane. This atmosphere most likely originates from Triton’s volcanic activity, which is driven by seasonal heating by the Sun. Triton, Io and Venus are the only bodies in the solar system besides Earth that are known to be volcanically active at the present time.

Triton is one of the coolest objects in our solar system. It is so cold that most of Triton’s nitrogen is condensed as frost, giving its surface an icy sheen that reflects 70 percent of the sunlight that hits it.”



“A team of researchers from the U.K. and the Netherlands has found evidence of carbonation in a meteorite that was found in the U.S. back in 1931—prior research has proven that the meteorite is actually a rock that was blown off the surface of Mars and landed on Earth approximately, 3000 years ago. This suggests, the researchers argue in their paper published in the journal Nature Communications, that Mars’ long ago atmosphere may not have escaped as has been suggested, but may instead be locked in its surface.”

More information: Sequestration of Martian CO2 by mineral carbonation, Nature Communications 4, Article number: 2662 DOI: 10.1038/ncomms3662

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