All posts tagged: early Earth

No proteins required: Newly discovered enzyme can hunt and mend broken RNA

No proteins required: Newly discovered enzyme can hunt and mend broken RNA

Published by Jenni Sidey

The oldest question in biology has a trap built into it. DNA holds the instructions for making proteins. Proteins are needed to copy, repair, and read DNA. Each depends on the other, which raises an obvious problem: how did either one get started? The most popular answer is that neither came first. Before both, there was RNA, a single molecule able to do two jobs at once, storing genetic information like DNA and speeding up chemical reactions like a protein. That idea, the RNA World hypothesis, has one persistent weakness. For an RNA-based lifeform to survive, it needed a way to fix its own genetic material when it broke, and no one had shown that RNA could do that repair job by itself. A team led by biochemist Saurja DasGupta at the University of Notre Dame now has, published in Nature Communications. And the way they found it was almost entirely by accident. Saurja DasGupta, Assistant Professor of Chemistry & Biochemistry. (CREDIT: Matt Cashore/University of Notre Dame) An Experiment That Went Sideways DasGupta’s lab was …

Sugar found in interstellar space may have seeded life on Earth

Sugar found in interstellar space may have seeded life on Earth

Published by Jenni Sidey

A sugar found in raspberries and sunless tanning products has turned up near the Milky Way’s center. The discovery marks the first direct detection of a true sugar in interstellar space, and it complicates a familiar view of cosmic chemistry. The molecule, erythrulose, was identified in the molecular cloud G+0.693−0.027, about 8.2 kiloparsecs from Earth. The cloud lies in the Galactic Center region and ranks among the richest known reservoirs of complex molecules. An international team led by Izaskun Jiménez-Serra of Spain’s Center for Astrobiology, or CAB, matched 12 sets of radio signals from the cloud with erythrulose’s laboratory spectrum. Those sets accounted for 17 individual transitions. The result matters because sugars sit at the heart of biology. They form part of DNA and RNA and support metabolism. Yet origin-of-life experiments have struggled to produce them efficiently under conditions thought to resemble early Earth. Astronomers detected erythrulose in a Galactic Center cloud, revealing a possible cosmic source of sugars for early Earth. (CREDIT: Wikimedia / AI-Generated / CC BY-SA 4.0) A chemical signal in a …

Water seeping into Earth’s mantle 3.1 billion years ago fueled early volcanic activity and plate tectonics

Water seeping into Earth’s mantle 3.1 billion years ago fueled early volcanic activity and plate tectonics

Published by Jenni Sidey

Water may have been shaping Earth’s deep interior far earlier than many geologists thought. In rocks more than 3 billion years old from Western Australia, a research team found chemical signs that water had already travelled down into the mantle, where it helped generate magma and fuel volcanic activity. That matters because the modern planet depends on this kind of deep recycling. Today, water is dragged into the mantle at subduction zones, where one tectonic plate slides beneath another. The process helps drive volcanism, build continents and regulate chemical cycles tied to habitability. But whether anything similar could happen on the much hotter early Earth has remained a stubborn question. The new evidence comes from the Whundo Group in the Pilbara Craton, one of the rare places where very old crust is still well preserved. The rocks formed about 3.13 billion to 3.10 billion years ago, and the team says they preserve an unusually clear record of how magma formed in a young planet that did not yet operate like the Earth of today. “These …

Lunar meteorite discovery reveals violent chapter in the inner solar system 3.5 billion years ago

Lunar meteorite discovery reveals violent chapter in the inner solar system 3.5 billion years ago

Published by Jenni Sidey

Earth’s earliest chapter is mostly gone. Rocks from the planet’s first few billion years have been eroded, buried, recycled, or dragged back into the mantle. This has left only scattered traces of the world in which life first appeared. Therefore, every surviving clue is unusually valuable, especially when scientists are trying to answer a basic question. How often did giant impacts strike the young inner solar system while life was beginning on Earth? A lunar meteorite recovered in northwest Africa is now offering one of those clues. In a study published in Geology, researchers report that the rock records a major impact on the Moon about 3.486 billion years ago. The age closely matches evidence of ancient impacts preserved on Earth. It also matches impact ages tied to 4 Vesta, the fourth-largest object in the asteroid belt. That rare overlap, the team says, helps connect the histories of three different bodies at a time when the inner solar system was still getting hammered. This happened long after the most chaotic phase of planet formation had …

Continent formation may have set the stage for life on Earth

Continent formation may have set the stage for life on Earth

Published by Jenni Sidey

Long before forests, fish, or even single cells, Earth may have needed something as unglamorous as growing continents to make life possible. A study in Terra Nova argues that the planet’s earliest continental crust did more than reshape the surface. In addition, it may have acted as a chemical regulator, drawing down dangerously high levels of boron from ancient oceans. Eventually, this helped create conditions that favored the chemistry behind life’s beginnings. That idea turns on a delicate balance. Boron has long been considered useful in prebiotic chemistry because borate can help stabilize ribose, a fragile sugar tied to RNA, the molecule many scientists think came before DNA. Yet boron is only helpful in the right range. Too little may have made it irrelevant. Too much may have pushed surface waters into forms that life could not use. “What we’re talking about is a geological control system for Earth’s surface chemistry,” said Dr. Brendan Dyck, an associate professor of Earth and environmental sciences at UBC Okanagan’s Irving K. Barber Faculty of Science. “The growth of …

Ancient impact with Theia may have brought water and life to Earth

Ancient impact with Theia may have brought water and life to Earth

Published by Jenni Sidey

Earth’s story may have hardened into place almost as soon as the Solar System began. That is the striking claim in new research tracing when the young planet locked in the chemical makeup that still defines it. According to the analysis, proto-Earth appears to have reached that point no later than about 3 million years after the first solids formed in the Solar System, an eye blink in planetary terms. Yet that early world was probably nothing like the one you know now. It was likely dry, depleted in volatile elements, and missing much of what life would later need. The work points to a two-stage history. First came a fast chemical settling of the material that built Earth’s main body. Much later, a giant impact may have supplied the water and other volatile ingredients that made the planet habitable. The result shifts the timing. It also changes the mood of Earth’s origin story. ε53Cr evolution of CCs and their intersection ages (model ages) with the bulk Solar System. (CREDIT: Science Advances) Instead of a …

Newly discovered Asgard microbe could explain the origins of complex life on Earth

Newly discovered Asgard microbe could explain the origins of complex life on Earth

Published by Jenni Sidey

At first sight, stromatolites may seem unremarkable. The stromatolite formations found in Shark Bay, Western Australia, do resemble dark, sediment-covered stones resting in shallow waters. However, they are rich in history through their layers of microbial life, whose interactions have occurred over time and are most likely indicative of a major occurrence in the timeline of Earth’s evolution. Stromatolites likely represent not only a cradle for the early evolution of microbial organisms’ interactions with one another, but also a model to understand how complex eukaryotic organisms may have arisen from these interactions in a long-term evolutionary progression. Although this idea as to how complex life originated may be a bold one, it builds on an age-old question. Approximately 2.3 billion to 2.1 billion years ago, it is believed that the first eukaryotic cells came into existence through a close association between an archaeal cell and a bacterium. Eventually, as the bacterial partner became an essential organelle in the eukaryotic cell, the mitochondrion, this close association or cooperation between the two cells directly contributed to the …

New study challenges where life first began on Earth

New study challenges where life first began on Earth

Published by Jenni Sidey

A major impact can eradicate entire ecosystems. It can melt rocks, send debris around the planet, and create a dent in the crust. Additionally, the heat released from the object may provide an environment suitable for the beginning of the process of life. In their study, they examined the similarities and differences between impact craters and the associated hydrothermal systems that would have resulted from the impact. They compared these systems to deep-sea hydrothermal vents. These vents have been a focus of many scientists when trying to understand the origins of life on Earth. “We do not know, from a scientific point of view, how life could have been created out of a lifeless early Earth,” said Cinquemani. “From where did something come from nothing?” Diagram of the thermobaric phase of an impact crater and its forming hydrothermal vent system. This phase corresponds with high temperatures, high pressure, melted impact sheet, and shock effects, both local and distant. (CREDIT: Journal of Marine Science and Engineering) Hydrothermal Vents and The Origins of Life Heat, water, and …

Earth’s tectonic plates were already shifting 3.5 billion years ago

Earth’s tectonic plates were already shifting 3.5 billion years ago

Published by Jenni Sidey

The rocks didn’t look like much from the outside. Scattered across a remote stretch of western Australia called North Pole Dome, they were ancient, weathered, and largely ignored for the better part of Earth’s history. But locked inside those formations, in tiny magnetic minerals no larger than grains of dust, was a record of something that geologists have argued about for decades. Earth’s outer shell was moving. And it was doing so 3.5 billion years ago. A study published in Science, led by researchers from Harvard’s Department of Earth and Planetary Sciences, presents what the authors describe as the oldest direct evidence yet of plate movement. The work doesn’t end a long-running debate about when modern plate tectonics began. However, it does push the story much deeper into the planet’s past than many scientists expected. A Two-Year Hunt Inside Ancient Stone The researchers focused on the Pilbara Craton, a fragment of early Earth in western Australia that ranks among the best-preserved pieces of Archean rock on the planet. These formations date to a time when …