Evidence from an ancient section of the Earth’s crust suggest that Earth was once a water-world, some three billion years ago. If true, it’ll mean scientists need to reconsider some thinking around exoplanets and habitability. They’ll also need to reconsider their understanding of how life began on our planet.

A new paper presents these results in the journal Nature Geoscience. The title of the paper is “Limited Archaean continental emergence reflected in an early Archaean ¹⁸O-enriched ocean.” The co-authors are Boswell Wing of the University of Colorado, Boulder, and his former post-doc student, Benjamin Johnson at Iowa State University.

The work is focused on an area in the Australian Outback called the Panorama district. In that region in northwestern Australia there’s a slab of ocean floor 3.2 billion years old, that’s been turned on its side. The chunk of crust holds chemical clues about ancient Earth’s seawater.

“There are no samples of really ancient ocean water lying around, but we do have rocks that interacted with that seawater and remembered that interaction,” Johnson said in a press release.

“The origin and evolution of Earth’s biosphere were shaped by the physical and chemical histories of the oceans.”

From the paper “Limited Archaean continental emergence reflected in an early Archaean ¹⁸O-enriched ocean.

The authors wanted to re-boot the debate over what ancient Earth looked like, and to break new ground in the discussion.

In the introduction to their paper, the two authors say “The origin and evolution of Earth’s biosphere were shaped by the physical and chemical histories of the oceans. Marine chemical sediments and altered oceanic crust preserve a geochemical record of these histories. Marine chemical sediments, for example, exhibit an increase in their ¹⁸O/¹⁶O ratio through time.” 

Marine sediments have been well-studied over time, but the authors of this study looked at the ancient crust instead. The ancient oceans held different types of oxygen that were then deposited into the crust. The scientists gathered over 100 samples of the ancient rock and analyzed it for two oxygen isotopes: oxygen-16 and oxygen 18. They wanted to find the relative amount of each isotope in the ancient crust, to compare it to the amounts in the sediment.

Their results showed more oxygen-18 in the crust when it was formed 3.2 billion years ago, meaning the ocean at that time had more oxygen-18. The pair of researchers say that means that when that crust formed, there were no continents. This is because when continents form, they contain clays, and those clays would have absorbed the heavier oxygen-18. So if there had been continents 3.2 billion years ago, their crust samples would have held less oxygen-18.

The over-arching conclusion of their work is that the Earth’s oceans went through two distinct states: one prior to continents forming, and one after continents formed.

Marine chemical sediments have been studied extensively to try to piece together continent formation on ancient Earth. As the study says, those ancient sediments include “carbonates, phosphates, microcrystalline silica and iron oxides. As these minerals form directly from aqueous species, they can reflect the ?¹⁸O of the water with which they coexist.” The sediments are like an archival record of Earth at the time, and the older sediments show oxygen-18 values increasing steadily through time, all the way up to today. But this work contrasts with that, and the authors suggest that seawater oxygen-18 decreased through time.

The pair of scientists constructed a model for ancient Earth, showing that “the initiation of continental weathering in the late Archaean, between 3 and 2.5 billion years ago, would have drawn down an ¹⁸O-enriched early Archaean ocean to ?¹⁸O values similar to those of modern seawater.” So only after continents formed, could the oxygen-18 values begin to look like modern values.

Although this study points to the possibility of ancient Earth as a water-world, it doesn’t mean that the planet was without any land-forms. Island-size areas of land, or even micro-continents, may have existed at the time, volcanic in nature, and very rocky. But the types of vast land-forms that cover the Earth today, rich in soil and with tall mountain ranges, may not have existed. If they had, the oxygen-18 content would have more closely resembled today’s.

“There’s nothing in what we’ve done that says you can’t have teeny, micro-continents sticking out of the oceans,” Wing said in a press release. “We just don’t think that there were global-scale formation of continental soils like we have today.”

The authors aren’t suggesting that their work is the definitive piece of evidence in the ongoing discussion around early Earth. They note that their are other possible reasons for their results.

If the ancient continents formed much more slowly than modern continents, that could explain the the discrepancy in oxygen-18. It’s also possible that the clays that absorb oxygen-18 formed in the ocean itself, rather than on the continents.

That points to an enduring mystery in Earth science: when exactly did continents form?

It’s likely, according to some evidence, that the continents could only form as the Earth’s core shed heat and cooled down. In any case, modern continents didn’t take shape until after the Jurassic. Prior to that, the single super-continent of Gondwana covered about one-fifth of the Earth’s surface. Wing wants to examine younger areas of the Earth’s crust to try to determine more clearly when the modern continents formed.

This study also touches on early life on Earth, and how and when it formed. Earth’s early oceans, much like modern oceans, acted as a buffer, which “mediated climatic feedbacks between the biosphere, atmosphere and geosphere through deep time, helping to ensure long-term planetary habitability.”

Science has painted a picture of what the early Earth may have looked like, and what the nature of the oceans was. But it’s far from complete. The evidence is all buried, in rock and in time. And as we seek to understand climate change here on Earth, and as we get better and better looks at exoplanets, all these questions about ancient Earth, the oceans, and the biosphere, take on new importance.

As the authors say in their paper, “An early Earth without emergent continents may have resembled a ‘water world’, providing an important environmental constraint on the origin and evolution of life on Earth as well as its possible existence elsewhere.“

“The history of life on Earth tracks available niches,” said Wing. “If you’ve got a waterworld, a world covered by ocean, then dry niches are just not going to be available.”

This job opportunity is out of this world — literally. For the first time in over four years, NASA is accepting applications for its next crop of astronauts, the agency announced Monday.

Not every space hopeful will get to don the iconic astronaut suit, however. Applicants must be U.S. citizens and meet one of the stringent education requirements, which include having either a master’s degree in a STEM field, a medical degree, or a combination of a STEM degree and test pilot training.

Potential astronauts must also have at least two years of related professional experience — or have completed at least 1,000 hours of “pilot-in-command time” in jet aircraft. Then they still have to pass NASA’s long-duration spaceflight physical.

Applicants are required to complete an online assessment that can take up to two hours to finish. The deadline to apply is March 31.

The agency announced last month that it would begin hiring new astronauts, but just began accepting applications Monday.

The opportunity comes as NASA moves ahead with plans to send the first woman and next man to the moon by 2024 with its Artemis program.

The Artemis mission seeks to “demonstrate new technological advancements and lay the foundation for private companies to build a lunar economy.” The goal is to have humans explore the moon’s South Pole surface for the first time ever and lay the groundwork for human missions to Mars later this century.

“America is closer than any other time in history since the Apollo program to returning astronauts to the Moon,” NASA Administrator Jim Bridenstine said in a press release. “We’re looking for talented men and women from diverse backgrounds and every walk of life to join us in this new era of human exploration that begins with the Artemis program to the Moon. If you have always dreamed of being an astronaut, apply now.”

The final astronaut candidates are expected to be selected by the middle of next year and would then begin training as the next class of Artemis Generation astronauts, according to NASA.

In 2015, when the agency was last looking for new astronauts, more than 18,000 people applied. Following over two years of “intensive training,” 11 new astronauts made the cut and graduated in a public ceremony in January. A member of that class, Jonny Kim, notably became NASA’s first Korean-American astronaut.

“Becoming an astronaut is no easy task, because being an astronaut is no easy task,” said Steve Koerner, NASA’s director of flight operations and chair of the Astronaut Selection Board. “Those who apply will likely be competing against thousands who have dreamed of and worked toward going to space for as long as they can remember. But somewhere among those applicants are our next astronauts, and we look forward to meeting you.”

NASA has chosen 350 people to train as astronaut candidates since the 1960’s and currently has 48 astronauts in its “active astronaut corps.”

CANBERRA, Australia (AP) — National news agency Australian Associated Press said Tuesday it was closing after 85 years, blaming a decline in subscribers and free distribution of news content on digital platforms.

“The saddest day: AAP closes after 85 years of excellence in journalism. The AAP family will be sorely missed,” AAP Editor-in-Chief Tony Gillies said in a tweet.

AAP’s more than 170 journalists will cease operations by June 26. Its Pagemasters editorial production service will also close at the end of August, the company said.

“The unprecedented impact of the digital platforms that take other people’s content and distribute it for free has led to too many companies choosing to no longer use AAP’s professional service,” the company said in a statement. “We have reached the point where it is no longer viable to continue.”

Sydney-based AAP is renowned for its fair and impartial reporting as well as its extraordinary reach across rural and urban Australia.

The Australian Parliament applauded AAP for its contributions an hour after its demise was made public .

“When you have such an important institution such as AAP coming to an end, … that is a matter of real concern,” Prime Minister Scott Morrison told Parliament.

Opposition leader Anthony Albanese said, “Today is a tragedy for our democracy.”

“You will leave a massive void in terms of information coverage,” he added.

AAP Chairman Campbell Reid said the organization had been for generations “journalism’s first responder.”

“It is a great loss that professional and researched information provided by AAP is being substituted with the un-researched and often inaccurate information that masquerades as real news on the digital platforms,” Reid said.

AAP’s domestic nationwide news coverage with bureaus in every state and territory is complemented by alliances with major international news agencies including The Associated Press.

The AP licenses its news text and photo services to AAP for redistribution into the Australian media market and its customers. AP is also contracted to use AAP text and photos.

AAP was started in 1935 by newspaper publisher Keith Murdoch, father of News Corp. founder Rupert Murdoch.

AAP is owned by Australian news organizations News Corp. Australia, Nine Entertainment Co., Seven West Media and Australian Community Media.

The first inkling that most AAP staff had that their jobs were in danger came on Monday with a Nine newspapers’ report that noted the weakest advertising market since the global financial crisis in 2008.

AAP made a modest 929,000 Australian dollar ($608,000) profit last year on AU$65,674,000 ($43 million) revenue.

AAP management broke the news of the closure to staff on Tuesday afternoon.

“We are obviously devastated by the news,” AAP Canberra Bureau Chief Paul Osborne said.

“But we are proud of AAP’s achievements over 85 years and know that everyone who worked on the wire gave it their all, in the name of fair, balanced and accurate reporting, ” the 20-year AAP veteran said.

AAP Melbourne reporter Benita Kolovos described as “heartwarming” the sight of #saveAAP trending on Twitter on Tuesday afternoon.

“I work with the best women and men and hope I will continue to be able to,” Kolovos tweeted. “Impartial journalism is vital to our democracy. Without it, the public will be worse off.”

Her Melbourne colleague Karen Sweeney noted that AAP’s top 10 sports stories on Monday were published 1,595 times and top 10 news stories were published 2,514 times.

“That’s 4109 blank spaces on websites and newspapers, dead air on radio that would need to be filled without us,” Sweeney tweeted.

AAP Brisbane reporter Christine Flatley described her workplace since 2006 as “hands down the best news organization I have worked for.”

Australian media organizations are under mounting financial pressure with global digital giants Google and Facebook taking a growing chunk of advertising revenue.

Media Entertainment and Arts Alliance, the journalists’ union, described the decision to shut down AAP as a “gross abandonment of responsibility by its shareholders — Australia’s major media outlets.”

“Bean-counters at the top of media organizations might think they can soldier on without AAP, but the reality is it will leave a huge hole in news coverage,” the union’s federal president, Marcus Strom, said in a statement.

“Filling those holes will fall to already overburdened newsroom journalists. Or coverage will simply cease to occur,” he said.

SpaceX is planning a huge boost to the number of rocket launches from its Florida launch sites in the next few years as the company builds its Starlink satellite megaconstellation while meeting flight demands from its customers, according to a federal environmental report.

The missions for SpaceX’s Falcon 9 and Falcon Heavy rockets will also have more options than in the past, according to the report, which was first reported by SpaceNews. One change will be a new mobile service tower allowing some missions to be assembled vertically, rather than horizontally. Another will be the capability to launch to polar orbits — quite the feat, since Florida is located close to the equator and better optimized for missions that operate close to the equator. SpaceX also plans to test recovering payload fairings as the company pushes for greater mission reusability.

By 2023, the company wants to launch 70 missions a year from its two Florida launch sites at the Kennedy Space Center and nearby Cape Canaveral Air Force Station, using Falcon 9 and Falcon Heavy rockets. This rate is a seven-fold increase from the 11 missions SpaceX put into orbit in 2019, and almost double the 38 planned launches in 2020. That information comes from a draft environmental assessment published Thursday (Feb. 27) by the Federal Aviation Administration’s Office of Commercial Space Transportation.

“This launch schedule is based on SpaceX’s anticipated need to support NASA and DoD [Department of Defense] missions, as well as commercial customers,” the assessment reads in part. “In addition to its typical launch trajectories, SpaceX is proposing … to include a new Falcon 9 southern launch trajectory to support missions with payloads requiring polar orbits. SpaceX estimates approximately 10 percent of its annual Falcon 9 launches would fly this new southern launch trajectory.”

SpaceX has two launch sites in Florida. One is at the historic Launch Complex 39A (LC-39A) of NASA’s Kennedy Space Center and the other is located Space Launch Complex 40 of the Cape Canaveral Air Force Station. The company also has two rocket landing pads at the Air Force Station. Its drone ship “Of Course I Still Love You,” used for rocket landings at sea, is based in Cape Canaveral, as are two payload fairing recovery ships and a Dragon spacecraft recovery ship.

The Hawthorne, California-based company also has a West Coast launchpad at California’s Vandenberg Air Force Base, with a second drone ship available for offshore landings. SpaceX’s first rocket, the Falcon 1, launched from Kwajalein Atoll in the Marshall Islands of the Pacific Ocean.

Polar launches and a Mobile Service Tower

The new polar trajectory would require missions to fly alongside the Florida coast to reach the correct orbit, which could generate sonic booms. The SpaceNews report, citing a March 2019 assessment by Blue Ridge and Consulting included as an appendix to the FAA’s document, says there would be a “low probability of structure damage (to glass, plaster, roofs, and ceilings) for well-maintained structures” in that area, assuming a peak overpressure of 4.6 pounds per square foot under typical flight trajectory and atmospheric conditions.

The mobile service tower would be used for a variety of launches, including security missions from the United States Air Force. The FAA states it will be built on SpaceX’s existing launch pad at LC-39A at the Kennedy Space Center, standing about 284 feet (86 meters) tall and 118 feet (35 meters) wide on its longest side. Any lighting for the tower would be constructed to comply with local environmental regulations concerning sky glow, the FAA added.

SpaceX plans to recover payload fairings, in which satellites are stored during launch, “using power boats to ‘chase and catch’ the chutes and the fairings,” FAA said. SpaceX caught half of a fairing on June 25, 2019 after a Falcon Heavy launch, and it hopes to recover three payload fairings a month between 2020 and 2025. This could lead to an environmental problem.

“During these six years, SpaceX anticipates up to 432 drogue parachutes and up to 432 parafoils would land in the ocean,” the FAA stated. “SpaceX would attempt to recover all parafoils over this time period, but it is possible some of the parafoils would not be recovered due to sea or weather conditions at the time of recovery.” There is a backup available if the power boats fail, which is using a salvage ship that could track down the fairing using GPS data and strobe lights located on the fairing data recorders. That said, recovery could be impossible “if sea or weather conditions are poor,” the FAA said.

SpaceX’s rocket fleet

Of note, the report covers activities from Falcon 9 and Falcon Heavy launches and makes few mentions of Starship, which is SpaceX’s forthcoming larger rocket system that could take on even heavier launches. The FAA noted, however, that “as Starship/Super Heavy launches gradually increase over time to 24 launches per year, the number of Falcon launches would decrease.”

FAA issued the report because “SpaceX’s launch manifest includes more annual Falcon launches and Dragon reentries than were considered in previous … analyses,” the FAA stated in the executive summary. This launch activity could affect both humans and animals in the region — which is relevant since part of the downrange launch zone is a protected area filled with marine mammals, sea turtles, and sharks, the FAA said. That said, the report does not contain a detailed list of which missions would be launched under the accelerated launch schedule.

While few details are available about SpaceX’s plans, in general the company has made announcements that do point to far more launch activity in the coming years. SpaceX is in the midst of building out its Starlink constellation, which could include as many as 42,000 individual satellites. The satellites are being launched into space at a rate of one launch every few weeks.

The company is also planning to launch humans from Florida’s Space Coast for the first time when its Dragon spacecraft is certified under NASA’s Commercial Crew program, which could happen as early as this year. No astronauts have been launched from this area since the end of the space shuttle program in 2011. That said, the normal pace of International Space Station flights from Kazakhstan (the only spot that sends humans to space right now) is about four launches a year, which is an appreciably lower rate than the Starlink lauches.

FAA proposes to modify or issue new launch licenses to SpaceX for Falcon rocket launches, and to issue new licenses for Dragon spacecraft reentry operations. The report is open to public comment until March 20, and the FAA urges all commenters to make their remarks “as specific as possible, and address the analysis of potential environmental impacts and the adequacy of the proposed action or merits of alternatives, and any mitigation being considered.”

A new ban on single-use plastic bags in New York left shoppers used to their old ways shocked at the new changes Sunday.

“I think it’s ridiculous,” letter-carrier Scott Kimmel, 56, told the New York Post while shopping at a Target in College Point, Queens. “I understand about ‘conserve, take care of the environment,’ but c’mon!”

New York officially prohibited stores from handing out most thin plastic bags starting Sunday.

State environmental officials were encouraging New Yorkers to start using reusable bags often made out of canvas or polyester. They said the state has purchased over a quarter-million reusable bags to give out to food pantries and shelters.

“I was totally shocked,” Target shopper Richie Alvarez, 49, added of the change. “This is what our world is coming to. Yeah, they charged me extra for the bag. That’s why I only took one. It would normally be two or three bags.”

The law, which the state passed last April, barred many types of businesses from using the thin plastic bags that have been clogging up landfills, getting tangled in trees and accumulating in lakes and seas.

Single-use paper bags will still be allowed, but counties had the option of imposing a 5-cent fee.

The state has planned to enforce the ban by issuing a warning to stores that violate the law for the first time. Each store eventually could face a $250 fine for a subsequent violation, and a $500 fine for violations in the same calendar year.

New York’s ban exempted bags used for restaurant takeout food, plastic bags used to wrap meat and bags used for prepared food.

“Plastic bags are officially banned,” the city posted on Twitter. “Together, we can create a cleaner future for our city and planet.”

The change seemed to affect residents who are elderly or of lesser means.

“This is nonsense,” said Constance Tripoli, 53, in Brooklyn. “I ain’t got no SUV like the mayor to take my groceries home. I told them I needed bags, and they snuck me a few.”

McDonald’s has blessed March 2 as National Egg McMuffin Day, which is good news for breakfast enthusiasts.

The fast food giant took to Twitter Friday to announce that customers can get a free Egg McMuffin Monday.

“What’s better than breakfast? A FREE Egg McMuffin for breakfast,” the restaurant tweeted.

You can get yours by ordering on the McDonald’s app. It’s free on the App Store and Google Play.

To take advantage, order between 6 a.m. and 10:30 a.m.