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What the rise of oxygen on early Earth tells us about life on other planets – Phys.org

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McGill University’s Professor Galen Halverson explores for ironstone deposits along a rocky ridge in the Wernecke Mountains (Yukon, Canada). Credit: Maxwell Lechte

When did the Earth reach oxygen levels sufficient to support animal life? Researchers from McGill University have discovered that a rise in oxygen levels occurred in step with the evolution and expansion of complex, eukaryotic ecosystems. Their findings represent the strongest evidence to date that extremely low oxygen levels exerted an important limitation on evolution for billions of years.

“Until now, there was a critical gap in our understanding of environmental drivers in early evolution. The early Earth was marked by low levels of oxygen, till surface rose to be sufficient for animal life. But projections for when this rise occurred varied by over a billion years—possibly even well before animals had evolved,” says Maxwell Lechte, a postdoctoral researcher in the Department of Earth and Planetary Sciences under the supervision of Galen Halverson at McGill University.

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Ironstones provide insights into early life

To find answers, the researchers examined iron-rich sedimentary rocks from around the world deposited in ancient coastal environments. In analyzing the chemistry of the iron in these rocks, the researchers were able to estimate the amount of oxygen present when the rocks formed, and the impact it would have had on early life like eukaryotic —the precursors to modern animals.

“These ironstones offer insights into the oxygen levels of shallow marine environments, where life was evolving. The ancient ironstone record indicates around less than 1% of modern oxygen levels, which would have had an immense impact on ecological complexity,” says Changle Wang, a researcher at the Chinese Academy of Sciences who co-led the study with Lechte.

What the rise of oxygen on early Earth tells us about life on other planets
Ironstones are sedimentary rocks deposited along coastlines millions of years ago, which contain abundant granules of iron oxides that contain chemical indicators of the amount of oxygen present at the time of formation. Credit: Maxwell Lechte

“These low oxygen conditions persisted until about 800 million years ago, right when we first start to see evidence of the rise of complex ecosystems in the record. So if complex eukaryotes were around before then, their habitats would have been restricted by low oxygen,” says Lechte.

Earth remains the only place in the universe known to harbor life. Today, Earth’s atmosphere and oceans are rich with oxygen, but this wasn’t always the case. The oxygenation of the Earth’s ocean and atmosphere was the result of photosynthesis, a process used by plants and other organisms to convert light into energy—releasing oxygen into the atmosphere and creating the necessary conditions for respiration and animal life.

Searching for signs of life beyond our solar system

According to the researchers, the new findings suggests that Earth’s atmosphere was capable of maintaining low levels of atmospheric oxygen for billions of years. This has important implications for exploration of signs of life beyond our solar system, because searching for traces of atmospheric oxygen is one way to look for evidence of past or present life on another planet—or what scientists call a biosignature.

What the rise of oxygen on early Earth tells us about life on other planets
Ironstones within the sedimentary rock layers of the Grand Canyon (Arizona, USA), preserving clues about ancient marine environments. Credit: Susannah Porter

Scientists use Earth’s history to gauge the oxygen levels under which terrestrial planets can stabilize. If terrestrial planets can stabilize at low atmospheric oxygen levels, as suggested by the findings, the best chance for oxygen detection will be searching for its photochemical byproduct ozone, say the researchers.

“Ozone strongly absorbs ultraviolet light, making detection possible even at low atmospheric oxygen levels. This work stresses that ultraviolet detection in space-based telescopes will significantly increase our chances of finding likely signs of life on planets outside our solar system,” says Noah Planavsky, a biogeochemist at Yale University.

More geochemical studies of rocks from this time period will allow scientists to paint a clearer picture of the evolution of oxygen levels during this time, and better understand the feedbacks on the global oxygen cycle, say the researchers.


Explore further

Study reveals more hostile conditions on Earth as life evolved 


More information:
Strong evidence for a weakly oxygenated ocean–atmosphere system during the Proterozoic, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2116101119.

Citation:
What the rise of oxygen on early Earth tells us about life on other planets (2022, January 31)
retrieved 31 January 2022
from https://phys.org/news/2022-01-oxygen-early-earth-life-planets.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
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Voyager 1 transmitting data again after Nasa remotely fixes 46-year-old probe – The Guardian

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Earth’s most distant spacecraft, Voyager 1, has started communicating properly again with Nasa after engineers worked for months to remotely fix the 46-year-old probe.

Nasa’s Jet Propulsion Laboratory (JPL), which makes and operates the agency’s robotic spacecraft, said in December that the probe – more than 15bn miles (24bn kilometres) away – was sending gibberish code back to Earth.

In an update released on Monday, JPL announced the mission team had managed “after some inventive sleuthing” to receive usable data about the health and status of Voyager 1’s engineering systems. “The next step is to enable the spacecraft to begin returning science data again,” JPL said. Despite the fault, Voyager 1 had operated normally throughout, it added.

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Launched in 1977, Voyager 1 was designed with the primary goal of conducting close-up studies of Jupiter and Saturn in a five-year mission. However, its journey continued and the spacecraft is now approaching a half-century in operation.

Voyager 1 crossed into interstellar space in August 2012, making it the first human-made object to venture out of the solar system. It is currently travelling at 37,800mph (60,821km/h).

The recent problem was related to one of the spacecraft’s three onboard computers, which are responsible for packaging the science and engineering data before it is sent to Earth. Unable to repair a broken chip, the JPL team decided to move the corrupted code elsewhere, a tricky job considering the old technology.

The computers on Voyager 1 and its sister probe, Voyager 2, have less than 70 kilobytes of memory in total – the equivalent of a low-resolution computer image. They use old-fashioned digital tape to record data.

The fix was transmitted from Earth on 18 April but it took two days to assess if it had been successful as a radio signal takes about 22 and a half hours to reach Voyager 1 and another 22 and a half hours for a response to come back to Earth. “When the mission flight team heard back from the spacecraft on 20 April, they saw that the modification worked,” JPL said.

Alongside its announcement, JPL posted a photo of members of the Voyager flight team cheering and clapping in a conference room after receiving usable data again, with laptops, notebooks and doughnuts on the table in front of them.

The Retired Canadian astronaut Chris Hadfield, who flew two space shuttle missions and acted as commander of the International Space Station, compared the JPL mission to long-distance maintenance on a vintage car.

“Imagine a computer chip fails in your 1977 vehicle. Now imagine it’s in interstellar space, 15bn miles away,” Hadfield wrote on X. “Nasa’s Voyager probe just got fixed by this team of brilliant software mechanics.

Voyager 1 and 2 have made numerous scientific discoveries, including taking detailed recordings of Saturn and revealing that Jupiter also has rings, as well as active volcanism on one of its moons, Io. The probes later discovered 23 new moons around the outer planets.

As their trajectory takes them so far from the sun, the Voyager probes are unable to use solar panels, instead converting the heat produced from the natural radioactive decay of plutonium into electricity to power the spacecraft’s systems.

Nasa hopes to continue to collect data from the two Voyager spacecraft for several more years but engineers expect the probes will be too far out of range to communicate in about a decade, depending on how much power they can generate. Voyager 2 is slightly behind its twin and is moving slightly slower.

In roughly 40,000 years, the probes will pass relatively close, in astronomical terms, to two stars. Voyager 1 will come within 1.7 light years of a star in the constellation Ursa Minor, while Voyager 2 will come within a similar distance of a star called Ross 248 in the constellation of Andromeda.

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iN PHOTOS: Nature lovers celebrate flora, fauna for Earth Day in Kamloops, Okanagan | iNFOnews | Thompson-Okanagan's News Source – iNFOnews

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This frog was spotted in a pond in the Kamloops area.
Image Credit: SUBMITTED/ Lyn MacDonald

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Photographers are sharing their favourite photos of flora and fauna captured in Kamloops and the Okanagan in celebration of Earth Day.

First started in the United States in the 70s, the special day on April 22 continues to be acknowledged around the globe. It’s a day to celebrate the planet and a reminder of the need for environmental conservation and sustainability, according to EarthDay.org.

These stunning nature photos show life in ponds and forests, in skies and on mountains, capturing the beauty and wonder of our local natural environments.

Area photographers shared some of their favourite finds and artistic captures. From frogs to flowers, the great outdoors is teeming with life. 

If you have nature photos you want to share, send them to news@infonews.ca.

The sun is touching the closed petals of a flower in Pinantan Lake near Kamloops.

The sun is touching the closed petals of a flower in Pinantan Lake near Kamloops.
Image Credit: SUBMITTED/ Patricia Hanson
This Great Grig was recently spotted in Penticton.

This Great Grig was recently spotted in Penticton.
Image Credit: SUBMITTED/ Luka Bevanda
 A snail appears to look at its reflection in a pond in the Slocan Valley.

A snail appears to look at its reflection in a pond in the Slocan Valley.
Image Credit: SUBMITTED/ Lyn MacDonald
A mother and baby coot paddle on a lake in Salmon Arm.

A mother and baby coot paddle on a lake in Salmon Arm.
Image Credit: SUBMITTED/ Grant Cruickshank
A wildflower bursts with colour in the South Thompson.

A wildflower bursts with colour in the South Thompson.
Image Credit: SUBMITTED/ Ann Steenhuysen
These pink flowers look like a string of decorations in Kamloops.

These pink flowers look like a string of decorations in Kamloops.
Image Credit: SUBMITTED/ Lyn MacDonald
A Townsend's Solitaire swoops into the air at Tunkwa Lake near Savona.

A Townsend’s Solitaire swoops into the air at Tunkwa Lake near Savona.
Image Credit: SUBMITTED/ Valerie Walsh
This flower in Kelowna is covered with raindrops.

This flower in Kelowna is covered with raindrops.
Image Credit: SUBMITTED/ Wendy Eiler

To contact a reporter for this story, email Shannon Ainslie or call 250-819-6089 or email the editor. You can also submit photos, videos or news tips to the newsroom and be entered to win a monthly prize draw.

We welcome your comments and opinions on our stories but play nice. We won’t censor or delete comments unless they contain off-topic statements or links, unnecessary vulgarity, false facts, spam or obviously fake profiles. If you have any concerns about what you see in comments, email the editor in the link above. SUBSCRIBE to our awesome newsletter here.

News from © iNFOnews, 2024

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An extra moon may be orbiting Earth — and scientists think they know exactly where it came from – Livescience.com

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A fast-spinning asteroid that orbits in time with Earth may be a wayward chunk of the moon. Now, scientists think they know exactly which lunar crater it came from.

A new study, published April 19 in the journal Nature Astronomy, finds that the near-Earth asteroid 469219 Kamo’oalewa may have been flung into space when a mile-wide (1.6 kilometers) space rock hit the moon, creating the Giordano Bruno crater.

Kamo’oalewa’s light reflectance matches that of weathered lunar rock, and its size, age and spin all match up with the 13.6-mile-wide (22 km) crater, which sits on the far side of the moon, the study researchers reported.

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China plans to launch a sample-return mission to the asteroid in 2025. Called Tianwen-2, the mission will return pieces of Kamo’oalewa about 2.5 years later, according to Live Science’s sister site Space.com.

“The possibility of a lunar-derived origin adds unexpected intrigue to the [Tianwen-2] mission and presents additional technical challenges for the sample return,” Bin Cheng, a planetary scientist at Tsinghua University and a co-author of the new study, told Science.

Related: How many moons does Earth have?

Kamo’oalewa was discovered in 2016 by researchers at Haleakala Observatory in Hawaii. It has a diameter of about 100 to 200 feet (approximately 30 to 60 meters, or about the size of a large Ferris wheel) and spins at a rapid clip of one rotation every 28 minutes. The asteroid orbits the sun in a similar path to Earth, sometimes approaching within 10 million miles (16 million km).

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Follow-up studies suggested that the light spectra reflected by Kamo’oalewa was very similar to the spectra reflected by samples brought back to Earth by lunar missions, as well as to meteorites known to come from the moon.

Cheng and his colleagues first calculated what size object and what speed of impact would be necessary to eject a fragment like Kamo’oalewa from the lunar surface, as well as what size crater would be left behind. They figured out that the asteroid could have resulted from a 45-degree impact at about 420,000 mph (18 kilometers per second) and would have left a 6-to-12-mile-wide (10 to 20 km) crater.

There are tens of thousands of craters that size on the moon, but most are ancient, the researchers wrote in their paper. Near-Earth asteroids usually last only about 10 million years, or at most up to 100 million years before they crash into the sun or a planet or get flung out of the solar system entirely. By looking at young craters, the team narrowed down the contenders to a few dozen options.

The researchers focused on Giordano Bruno, which matched the requirements for both size and age. They found that the impact that formed Giordano Bruno could have created as many as three still-extant Kamo’oalewa-like objects. This makes Giordano Bruno crater the most likely source of the asteroid, the researchers concluded.

“It’s like finding out which tree a fallen leaf on the ground came from in a vast forest,” Cheng wrote on X, formerly known as Twitter.

Confirmation will come after the Tianwen-2 mission brings a piece of Kamo’oalewa back to Earth. Scientists already have a sample of what is believed to be ejecta from Giordano Bruno crater in the Luna 24 sample, a bit of moon rock brought back to Earth in a 1976 NASA mission. By comparing the two, researchers could verify Kamo’oalewa’s origin.

Editor’s note: This article’s headline was updated on April 23 at 10 a.m. ET.

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