13 replies to this topic

[wjfox]

This thread is for general news/discussions about the formation and early evolution of our planet.

 

So basically anything from the Hadean (4.4 billion BCE) to the early Phanerozoic/Cambrian (~530 million BCE).

 

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Asteroids may have delivered half of the water in Earth's oceans

 

May 1, 2019
 

Over 70 percent of Earth’s surface is covered in water, almost all of which is in the oceans. But where did all this water come from? Several hypotheses seek to explain how water arrived on our planet in the early days of its formation, including the idea that molecular water leaked out of hydrated minerals on Earth, and the possibility that asteroids and comets delivered water to Earth.

New research in the journal Science Advances lends support to the asteroid hypothesis, suggesting that these rocky visitors could have delivered up to half of Earth’s water billions of years ago.

 

https://www.inverse....ple-earth-water

 

 

[caltrek]

Scientists glimpse oddball microbe that could help explain rise of complex life

 

https://www.nature.c...02430-w#ref-CR1

 

Extract:

 

(Nature) Biologists have for the first time captured and grown an elusive type of microbe that is similar to those that might have given rise to all complex life on Earth.

 

In a preprint posted to the bioRxiv repository, scientists in Japan report that they have isolated and grown microbes from an ancient lineage of archaea — single-celled microbes that look, superficially, like bacteria but are quite distinct — that was previously known only from genomic sequences.

 

…One genome stood out. It was clearly a member of the archaea. But dotted throughout this genome were eukaryotic-like genes, suggesting to Ettema that this oddball could help to bridge the evolutionary gap between simpler microbes and eukaryotes. The researchers called it Lokiarchaea, after Loki, the trickster of Norse mythology.

 

Soon, other labs found additional Loki-like archaea, and together these formed the Asgard archaea, named after a mythological region inhabited by Norse gods. Although the organisms’ precise place in the tree of life remains contentious, many analyses pair Asgards and eukaryotes together, which could mean that some distant Asgard-like ancestor gave rise to all eukaryotes — everything from panda bears to portabello mushrooms.

 

…“We can’t just go back in time and observe what happened,” says Ettema. The Asgards we see today are not the same as the microbe that gave rise to eukaryotes. But he says that culturing more Asgards and studying what their eukaryotic-like genes actually do will give a fuller picture of the evolutionary tree, and help researchers to better infer how simple, single-celled organisms made the first giant leap towards complexity

Archaea are often found in extreme environments, such as these chimneys on the summit of Giggenbach underwater volcano, off New Zealand.

Credit: New Zealand-American Submarine Ring of Fire 2005 Exploration, NOAA Vents Program

[caltrek]

With a tip of the hat to Jessica for finding this article:

 

Genes that first enabled plants to grow leaves identified by scientists

 

https://phys.org/new...scientists.html

 

 

The genes that first enabled plants to grow shoots and conquer the land have been identified by University of Bristol researchers. The findings, published in Current Biology, explain how a 450-million years ago a switch enabled plants to delay reproduction and grow shoots, leaves and buds.

 

Over the course of half a billion years of evolution, plants have evolved from tiny and simple ground-hugging forms into diverse and complex varieties that abound the Earth today, from the garden rose to the 100-metre tall redwood tree. An international research team from the Universities of Bristol (UK), Lyon (France) and Palacký (Czech Republic) has now discovered the secrets of shoot evolution.

 

 

Moss.

Credit: Dr Jill Harrison

[Jessica]

Researchers discover oldest fossil forest in Asia

August 8, 2019
Source:
Cell Press

The Devonian period, which was 419 million to 359 million years ago, is best known for Tiktaalik, the lobe-finned fish that is often portrayed pulling itself onto land. However, the "age of the fishes," as the period is called, also saw evolutionary progress in plants. Researchers reporting August 8 in the journal Current Biology describe the largest example of a Devonian forest, made up of 250,000 square meters of fossilized lycopsid trees, which was recently discovered near Xinhang in China's Anhui province. The fossil forest, which is larger than Grand Central Station, is the earliest example of a forest in Asia.

Lycopsids found in the Xinhang forest resembled palm trees, with branchless trunks and leafy crowns, and grew in a coastal environment prone to flooding. These lycopsid trees were normally less than 3.2 meters tall, but the tallest was estimated at 7.7 meters, taller than the average giraffe. Giant lycopsids would later define the Carboniferous period, which followed the Devonian, and become much of the coal that is mined today. The Xinhang forest depicts the early root systems that made their height possible. Two other Devonian fossil forests have been found: one in the United States, and one in Norway.

"The large density as well as the small size of the trees could make Xinhang forest very similar to a sugarcane field, although the plants in Xinhang forest are distributed in patches," says Deming Wang, a professor in the School of Earth and Space Sciences at Peking University, co-first author on the paper along with Min Qin of Linyi University. "It might also be that the Xinhang lycopsid forest was much like the mangroves along the coast, since they occur in a similar environment and play comparable ecologic roles."

The fossilized trees are visible in the walls of the Jianchuan and Yongchuan clay quarries, below and above a four-meter thick sandstone bed. Some fossils included pinecone-like structures with megaspores, and the diameters of fossilized trunks were used to estimate the trees' heights. The authors remarked that it was difficult to mark and count all the trees without missing anything.

 

More:
https://www.scienced...90808111435.htm

[caltrek]

Earth's oldest crater found in Australia; asteroid may have helped thaw 'snowball Earth'

 

https://www.japantim...snowball-earth/

 

Introduction:

 

(Reuters) WASHINGTON – Scientists have identified Earth’s oldest-known impact crater, and in doing so may have solved a mystery about how our planet emerged from one of its most dire periods.

 

Researchers have determined that the 45-mile-wide (70-km) Yarrabubba crater in Australia formed when an asteroid struck Earth just over 2.2 billion years ago. The collision occurred at a time when the planet was believed to have been encased in ice and the impact may have driven climate warming that led to a global thaw.

 

“Looking at our planet from space, it would have looked very different,” said isotope geology professor Chris Kirkland of Curtin University in Australia, one of the researchers in the study published in the journal Nature Communications. “You would see a white ball, not our familiar blue marble.”

 

The researchers suspect the region was covered in an ice sheet up to 3 miles (5 km) thick at the time. They calculated that the violent asteroid strike may have transformed immense amounts of ice into water vapor — sending perhaps 200 billion tons of it billowing into the atmosphere. It would have served as a greenhouse gas trapping heat in the atmosphere.

 

The researchers are wondering whether this thaw helped shepherd Earth into a climate more favorable for the simple microbes that inhabited the planet at the time to thrive and evolve, possibly making it a pivotal event in the history of life on Earth.

[Jessica]

Ancient shell shows days were half-hour shorter 70 million years ago

From phys.org:

Earth turned faster at the end of the time of the dinosaurs than it does today, rotating 372 times a year, compared to the current 365, according to a new study of fossil mollusk shells from the late Cretaceous. This means a day lasted only 23 and a half hours, according to the new study in AGU's journal Paleoceanography and Paleoclimatology.

The ancient mollusk, from an extinct and wildly diverse group known as rudist clams, grew fast, laying down daily growth rings. The new study used lasers to sample minute slices of shell and count the growth rings more accurately than human researchers with microscopes.

The growth rings allowed the researchers to determine the number of days in a year and more accurately calculate the length of a day 70 million years ago. The new measurement informs models of how the Moon formed and how close to Earth it has been over the 4.5-billion-year history of the Earth-Moon gravitational dance.

The new study also found corroborating evidence that the mollusks harbored photosynthetic symbionts that may have fueled reef-building on the scale of modern-day corals.

 

more ...

[wjfox]

Solar system acquired current configuration not long after its formation

March 24, 2020

The hypothesis that the solar system originated from a gigantic cloud of gas and dust was first floated in the second half of the 18th century by German philosopher Immanuel Kant and further developed by French mathematician Pierre-Simon de Laplace. It is now a consensus among astronomers. Thanks to the enormous amount of observational data, theoretical input and computational resources now available, it has been continually refined, but this is not a linear process.

Nor is it without controversies. Until recently, the solar system was thought to have acquired its present features as a result of a period of turbulence that occurred some 700 million years after its formation. However, some of the latest research suggests it took shape in the more remote past, at some stage during the first 100 million years.

A study conducted by three Brazilian researchers offers robust evidence of this earlier structuring.

 

https://phys.org/new...-formation.html

 

 

[caltrek]

+1s for WJFox and Jessica.

[caltrek]

No asteroids needed: ancient mass extinction tied to ozone loss, warming climate

 

https://www.sciencem...ne-loss-warming

 

Introduction:

(Science) The end of the Devonian period, 359 million years ago, was an eventful time: Fish were inching out of the ocean, and fernlike forests were advancing on land. The world was recovering from a mass extinction 12 million years earlier, but the climate was still chaotic, swinging between hothouse conditions and freezes so deep that glaciers formed in the tropics. And then, just as the planet was warming from one of these ice ages, another extinction struck, seemingly without reason. Now, spores from fernlike plants, preserved in ancient lake sediments from eastern Greenland, suggest a culprit: The planet’s protective ozone layer was suddenly stripped away, exposing surface life to a blast of mutation-causing ultraviolet (UV) radiation.

 

Just as the extinction set in, the spores became misshapen and dark, indicating DNA damage, John Marshall, a palynologist at the University of Southampton, and his co-authors say in a paper published today in Science Advances. It’s evidence, he says, that “all of the ozone protection is gone.”

 

Scientists have long believed—at least before humanity became a force for extinction—that there were just two ways to wipe out life on Earth: an asteroid strike or massive volcanic eruptions. But 2 years ago, researchers found evidence that in Earth’s worst extinction—the end-Permian, 252 million years ago—volcanoes lofted Siberian salt deposits into the stratosphere, where they might have fed chemical reactions that obliterated the ozone layer and sterilized whole forests. Now, spores from the end-Devonian make a compelling case that, even without eruptions, a warming climate can deplete the ozone layer, says Lauren Sallan, a paleobiologist at the University of Pennsylvania. “Because the evidence is so strong, it will make people rethink other mass extinction events.”

An “overshooting” thunderstorm can inject water into the stratosphere, where it may destroy ozone.

NASA

[RyderKellaway]

very interesting topic, I’m just studying it, thanks for this topic

[wjfox]

[Time_Traveller]

The moon is 85 million years younger than previously thought

3 hours

 

It turns out the moon is a little younger than scientists previously thought — about 85 million years younger, to be precise.

In a new study, researchers at the German Aerospace Center found out that, not only did the moon once have a massive, fiery magma ocean, but our rocky satellite also formed later than scientists previously expected. 

 

Billions of years ago, a Mars-size protoplanet smashed into the young Earth and, amid the debris and cosmic rubble, a new rocky body formed — our moon. In this new work, the researchers reconstructed the timeline of the moon's formation. While scientists have previously thought that this moon-forming collision happened 4.51 billion years ago, the new work pegged the moon's birth at only 4.425 billion years ago.

 

https://www.space.co...an-thought.html

[Time_Traveller]

The electric hum of life may have originated with primordial lightning

A day ago

 

 

There's an electrical hum in most animals, including ourselves. No one knows where it came from or why exactly it exists. Now, new research suggests this electric hum came from primordial lightning. 

 

In most vertebrates and invertebrates, there is constant background cellular electrical activity, often coursing through the nervous system, with a small frequency range from 5 to 45 Hertz. A new study, published in the journal International Journal of Biometeorology, notes this extremely low frequency (ELF) range overlaps with natural vibrations in the atmosphere caused by lightning.

 

"About 20 years ago, we started to discover that many biological systems, from the simplest of organisms like zooplankton in the ocean to our brains, have electrical activity in exactly the same frequency range as that produced by global lightning activity," Colin Price, lead author on the new study and researcher at the Porter School of the Environment and Earth Sciences at Tel Aviv University in Israel, told Live Science. "We think that on evolutionary timescales, over billions of years, life-forms may have used what nature has given them and have somehow either synchronized to those frequencies or adapted to them."

 

https://www.space.co...-lightning.html

[caltrek]

Scientists have discovered a new candidate source for Earth’s water: building blocks known as enstatite chondrites.

 

https://skyandtelesc...f-earths-water/

 

Introduction:

(Sky & Telescope) We may finally have found the missing source of most of Earth's water in a rare class of meteorites called enstatite chondrites. These are remnants of the part of the protoplanetary disk from which the terrestrial planets formed. Their composition resembles Earth's, but they had been thought too dry to supply water.

 

Now, an analysis of the most pristine samples known shows that the original population might have supplied enough water to more than fill the oceans, Laurette Piani (University of Lorraine, France) and colleagues report in Science.   

 

Earth and the other terrestrial planets came together out of the solar nebula in a region thought to be too close to the young Sun for water to condense. Instead, water would have condensed beyond the snow line of the young solar system, out near Jupiter. If that were the case, delivering water to Earth in the early years of the solar system required a roundabout route.

 

The leading candidate for water delivery had been carbonaceous chondrite asteroids — rocky leftovers of the protoplanetary disk. Such asteroids formed beyond Jupiter and so would have been rich in carbon and water. But the material in those asteroids fails a crucial fingerprint test. To see if the water on Earth is the same as the water on asteroids, astronomers compare isotopes. Every atom of hydrogen, for example, has the same number of electrons and protons, but some have more neutrons than others. Based on the isotopic composition of hydrogen, oxygen, and other elements, scientists concluded that asteroids’ water and rocky materials do not match terrestrial ones. Much of the water and other materials must have come from other sources.

 

Enstatite chondrites formed in the first million years of the solar system, close to the Sun in an environment rich in gaseous carbon and oxygen compounds. Previous studies have found that isotopic ratios of a number of elements — including oxygen, calcium, titanium, neodymium, chromium, nickel, molybdenum, and ruthenium — are almost indistinguishable between these particular asteroids and Earth and the Moon.

 

Artist's illustration of a protoplanetary disk, like the one that existed in the solar system's earliest years.
ESO / L. Calçada