Slowdown of Earth's spin caused an oxygen surge
Here's a new spin on how Earth became an oxygen-rich planet: As our planet's rotation slowed, microbes were bathed in longer stints of sunlight that revved up their release of oxygen into the atmosphere.
Every breath you take is possible because billions of years ago, dense mats of cyanobacteria — the first life on Earth — began churning out oxygen as a byproduct from photosynthesis. But scientists still didn't know for sure what triggered two transformative oxygenation events that turned Earth from a low-oxygen planet into an oxygen-rich world where complex organisms could evolve and diversify.
Now, researchers have identified an important factor that could have spurred the release of microbial-generated oxygen: slowdowns in Earth's rotation beginning about 2.4 billion years ago. Earth spun more quickly when it was a newborn planet, completing a turn in just a handful of hours, but it gradually decelerated over hundreds of millions of years. Once the length of a day reached a certain threshold — possibly during those key oxygenation periods — longer stretches of sunlight may have enabled more oxygen molecules to hop from areas of high concentration (inside the bacteria mats) to areas of lower concentration (the atmosphere), according to a new study.
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Scientists recently found clues to this link in a sinkhole at the bottom of Lake Huron. Bordered by Michigan in the United States and by Ontario in Canada, Lake Huron is one of the biggest freshwater lakes in the world. The lake's Middle Island Sinkhole measures 300 feet (91 meters) in diameter and lies about 80 feet (24 m) below the surface. There, sulfur-rich water nourishes colorful microbes that thrive in a low-oxygen environment, much like Earth's earliest forms of bacteria did.
In the sinkhole's chilly depths live two types of microbes: sunlight-seeking purple cyanobacteria, which produce oxygen through photosynthesis, and white bacteria, which consume sulfur and instead release sulfate. The microbes jockey for position throughout the day, with the sulfur-eating bacteria covering their purple neighbors in the morning and evening hours, blocking the purple microbes' access to the sun. However, when daylight is strongest, the white microbes shun the light and migrate deeper into the sinkhole, leaving the purple cyanobacteria uncovered and thereby able to photosynthesize and release oxygen.
There might have been similar competitions between communities of microbes billions of years ago, with oxygen-producing bacteria's sunlight exposure hampered by their microbial neighbors, the researchers wrote in the study. Then, as days on Earth became longer, the oxygen-makers gained more time in the sunlight — and released more oxygen into the atmosphere.
"We realized that there is a fundamental link between light dynamics and release of oxygen, and that link is grounded in the physics of molecular diffusion," when thermal changes cause molecules to migrate from areas of higher concentration to lower ones, said study lead author Judith Klatt, a research scientist with the Max Planck Institute for Marine Microbiology in Bremen, Germany.
"A shorter day would allow less oxygen to escape a mat, even if the same amount of oxygen is produced per hour," Klatt told Live Science in an email.
Now, Earth completes a full rotation on its axis once every 24 hours, but more than 4 billion years ago, a day lasted only about six hours, the researchers reported. Over billions of years, Earth's ongoing dance with the moon has slowed the planet's rotation through a process known as tidal friction. As Earth rotates, the pull of the moon (and the sun, to a lesser extent) attracts Earth's oceans. This stretches the seas so that they bulge away from Earth's center, siphoning energy away from the spin and slowing it down, said study co-author Brian Arbic, a professor in the Earth and Environmental Sciences department at the University of Michigan's College of Literature, Science and the Arts.
This deceleration is small, but it added up to hours of additional daylight over hundreds of millions of years; and the slowdown is still going on today, Arbic told Live Science in an email.
"Tidal friction continues to slow down the rotation rate — the days will continue to lengthen over geological time," Arbic said.
Breath of fresh air
The researchers modeled scenarios that varied day length and oxygen escape from microbial mats. When they compared their models with an analysis of the competing microbial mats sampled from the Middle Island Sinkhole, they found confirmation of their predictions: Photosynthesizing bacteria released more oxygen when days were longer.
This wasn't because the microbes photosynthesized more; rather, it was because longer periods of sunlight meant that more oxygen escaped from the mats in a single day, said study co-author Arjun Chennu, a research scientist at the Leibniz Centre for Tropical Marine Research in Bremen.
"This subtle uncoupling of oxygen release from sunlight is at the heart of the mechanism," Chennu said in a statement.
Earth's atmosphere took shape after the planet formed and cooled, around 4.6 billion years ago, and was mostly made of hydrogen sulfide, methane and carbon dioxide (CO2) — as much as 200 times the amount of CO2 as there is in the atmosphere today, according to the Smithsonian Environmental Research Center.
That all changed following the Great Oxidation Event (GOE) about 2.4 billion years ago, followed by the Neoproterozoic Oxygenation Event about 2 billion years later, bringing atmospheric oxygen up to the present-day level of about 21%. Those two oxygenation events have previously been linked to the activity of photosynthesizing cyanobacteria, and this new evidence suggests that another factor could have been daytime on Earth — "a previously largely unconsidered factor" — becoming long enough to trigger the release of even more oxygen from microbial mats, working "in parallel with the other previously suggested drivers of oxygenation," Klatt said.
The findings were published on Aug. 2 in the journal Nature Geoscience.
Reference: Mindy Weisberger: Space.Com
Elon Musk’s SpaceX Starlink ‘plans ground station on the Isle of Man’ for blanket coverage of Britain
Elon Musk’s SpaceX Starlink ‘plans ground station on the Isle of Man’ for blanket coverage of Britain
Elon Musk’s Starlink space internet is setting up on the Isle of Man with plans for blanket coverage of Britain, a new report claims.
Starlink, which is developed by SpaceX, is reportedly in the final stages of getting a license to build a ground station on the island.
Alongside bases in Buckinghamshire and Cornwall, this means Starlink could provide full coverage across the country, the Telegraph reported, citing filings from the Isle of Man’s communications regulator.
Starlink acquired a license and the right to use spectrum bands and install equipment and was apparently the only one to express an interest in multiple spectrum bands.
In the UK, Starlink would charge customers £89 a month alongside a £439 fee for a satellite dish, with internet speeds expected to be around 150 megabits a second.
At the start of the year, it was reported that Ofcom had granted the company regulatory approval, which would see it compete with rival services like OneWeb.
Mr Musk has claimed that Starlink will likely move out of beta testing this summer. “Service uptime, bandwidth & latency are improving rapidly. Probably out of beta this summer”, Mr Musk tweeted in April 2021.
The change could mean more people will be able to sign up to the service, which currently has over 10,000 users.
However the program, which would require a network of tens of thousands of satellites, has been criticised as “extremely impactful” to astronomers’ scientific progress if more is not done to limit the impact of the satellites in the night sky.
Starlink did not respond to a request for comment from The Independent before time of publication.
This news comes after new regulations allow for space flights and satellite launches to be conducted in the UK.
Proposed locations for UK spaceports are Newquay in Cornwall, Snowdonia in North Wales, and the Western Isles, Glasgow, Machrihanish, Sutherland and Shetland, all in Scotland.
Space tourism trips and hypersonic flights - which are faster than the speed of sound - will eventually launch from the UK too, the Department for Transport said. The first launch is expected in 2022.
Reference: Independent: Adam Smith
Campaigners win High Court victory over Stonehenge tunnel project
Campaigners have won a High Court battle over Transport Secretary Grant Shapps’ decision to approve a controversial road project which includes a tunnel near Stonehenge
Save Stonehenge World Heritage Site (SSWHS) challenged his decision to back the £1.7 billion scheme to overhaul eight miles of the A303, including the two-mile tunnel.
The go-ahead was given in November last year, despite advice from Planning Inspectorate officials that it would cause “permanent, irreversible harm” to the Unesco World Heritage Site in Wiltshire.
In a ruling on Friday, Mr Justice Holgate found the decision was “unlawful” on two grounds.
He concluded that there was a “material error of law” in the decision-making process because there was no evidence of the impact on each individual asset at the historic site.
He also found that Mr Shapps failed to consider alternative schemes, in accordance with the World Heritage Convention and common law.
The judge said: “The relevant circumstances of the present case are wholly exceptional.
“In this case the relative merits of the alternative tunnel options compared to the western cutting and portals were an obviously material consideration which the (Transport Secretary) was required to assess.
“It was irrational not to do so. This was not merely a relevant consideration which the (Transport Secretary) could choose whether or not to take into account.
“I reach this conclusion for a number of reasons, the cumulative effect of which I judge to be overwhelming.”
John Adams, SSWHS director and acting chairman of the Stonehenge Alliance, said: “We could not be more pleased about the outcome of the legal challenge.
The judgment is a clear vindication of our client’s tremendous efforts in campaigning to protect the World Heritage Site
“The Stonehenge Alliance has campaigned from the start for a longer tunnel if a tunnel should be considered necessary.
“Ideally, such a tunnel would begin and end outside the WHS. But now that we are facing a climate emergency, it is all the more important that this ruling should be a wake-up call for the Government.
“It should look again at its roads programme and take action to reduce road traffic and eliminate any need to build new and wider roads that threaten the environment as well as our cultural heritage.”
Rowan Smith, a Leigh Day solicitor who represented the campaigners, said: “This is a huge victory, which means, for now, Stonehenge is safe.
“The judgment is a clear vindication of our client’s tremendous efforts in campaigning to protect the World Heritage Site.
“The development consent for this damaging tunnel has been declared unlawful and is now quashed, and the Government will have to go back to the drawing board before a new decision can be made.
“Meanwhile, one of the country’s most cherished heritage assets cannot be harmed.”
A panel of expert inspectors recommended that development consent should be withheld because the project would substantially and permanently harm the integrity and authenticity of the site, which includes the stone circle and the wider archaeology-rich landscape.
In a report to Mr Shapps, the officials said permanent, irreversible harm, critical to the outstanding universal value of the site, or why it is internationally important, would occur, “affecting not only our own, but future generations”.
The Stonehenge site, together with Avebury, was declared by Unesco to be a World Heritage Site of Outstanding Universal Value in 1986 on account of the size of the megaliths, the sophistication of their concentric plans and the complexes of Neolithic and Bronze Age sites and monuments.
The proposed tunnel is part of a £1.7 billion investment in the A303 between Amesbury and Berwick Down.
The road, which is a popular route for motorists travelling to and from the South West, is often severely congested on the single carriageway stretch near the stones.
Highways England says its plan for a two-mile tunnel will remove the sight and sound of traffic passing the site and cut journey times, but some environmentalists and archaeologists have voiced their opposition to the plan due to its potential impact on the area.
The project is classified as nationally significant, which means a development consent order is needed for it to go ahead.
A Historic England spokesperson said: “We are disappointed in the outcome of the Judicial Review. This is a missed opportunity to remove the intrusive sight and sound of traffic past the iconic monument and to reunite the remarkable Stonehenge landscape, which has been severed in two by the busy A303 trunk road for decades.
“We believe that the scheme had the potential to deliver a lasting positive legacy for the World Heritage Site and we advised on a rigorous programme of archaeological investigation to ensure the impact on sensitive archaeological remains was minimised.
“Stonehenge is one of the most important prehistoric landscapes in the world and has been of deep significance to people for over 5,000 years.
“We will continue work with partners in the heritage sector and to advise Highways England on any proposals for the A303.”
Reference: Evening Standard:
Briton among two killed in 'suspected drone attack' on tanker in Arabian Sea
A British security guard was among two crew members killed in what a UK source described as a suspected drone attack on an Israeli-linked oil tanker off Oman.
There has not been any official confirmation about what happened to the Mercer Street vessel, which is managed by a British company, and no one has claimed responsibility.
The UK source said that the crew had reported being targeted by "some sort of drone" on Thursday in the Arabian Sea before communications with the ship were lost.
If a drone attack is confirmed it would raise speculation about a possible link to a government or some kind of proxy group.
Iran in the past has repeatedly been accused of targeting tankers in the Gulf.
The country has been locked in a tit-for-tat contest with arch-rival Israel, with both sides accusing the other of targeting ships and launching cyber attacks.
Zodiac Maritime, the UK firm that manages the vessel, is part of Israeli billionaire Eyal Ofer's Zodiac Group.
It said "details of the incident are still being established and an investigation … is currently underway".
The tanker was on the move again, under the control of its crew, with a US naval escort to a safe location, Zodiac Maritime added, without specifying where it was headed.
The British national who was killed was working for the UK maritime security company Ambrey. The other fatality was a Romanian crew member.
A British government spokesman said: Our thoughts are with the loved ones of a British National who has died…
Vessels must be allowed to navigate freely in accordance with international law. We are working with our international partners to urgently establish the facts."
In a sign of the gravity of the situation, it is understood that Dominic Raab, the foreign secretary, is receiving regular updates.
The United Kingdom Maritime Trade Operations (UK MTO) - a part of the Ministry of Defence, which provides maritime security information - said what took place was a "non-piracy incident".
The Mercer Street tanker is Japanese owned but was sailing with a Liberian flag.
Concerns about a threat to tankers from Iran, following a spate of attacks in 2019, prompted the UK and its allies to send more warships to the Gulf to better protect the vital waterway.
The UK MTO said the vessel was about 152 nautical miles (280 km) northeast of the Omani port of Duqm when it was attacked on Thursday.
It gave no more details on the type of vessel, any cargo, to whom it belonged or about possible casualties.
Zodiac Maritime said in a statement: "We can confirm that there has been a suspected piracy incident onboard the product tanker M/T Mercer Street.
"The ship is a Japanese owned vessel managed by our UK based Zodiac Maritime Office. At the time of the incident, the vessel was in the northern Indian Ocean, travelling from Dar es Salaam to Fujairah with no cargo on board.
"We are in coordination and liaising with the UK MTO and other relevant authorities."
A spokesperson for the Ministry of Defence said: "We are aware of reports of an attack on a merchant vessel off the coast of Oman. UK military headquarters in the region are currently conducting investigations."
According to Eikon's ship tracking, the Mercer Street was headed to Fujairah, a bunkering port and oil terminal in the United Arab Emirates, from Dar es Salaam, in Tanzania.
Reference: Sky News: Deborah Haynes, foreign affairs editor
International Space Station knocked out of position as new Russian science lab malfunctions
The newly arrived lab accidentally fired its thrusters, resulting in the ISS losing control of its orientation for 47 minutes, NASA said.
Russian cosmonauts had been checking for leaks between the 22-tonne lab - named Nauka - and the service module, when automatic sensors on the ground detected the problem.
Communication between the station and ground controllers was also cut twice for a few minutes.
NASA said that the crew was "never and is not in any danger", adding that ground teams had regained control and the "motion of the space station is stable".
Joel Montalbano, manager of NASA's space station programme, said that, at the height of the incident, the ISS was pitching out of alignment at the rate of about half a degree per second.
The crew "really didn't feel any movement", he added.
Russian space officials were also unfazed, with Dmitry Rogozin, head of Roscosmos, tweeting: "All in order at the ISS. The crew is resting, which is what I advise you to do as well."
It is not yet clear why Nauka's thrusters malfunctioned.
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The 13m-long lab launched from Kazakhstan last week, taking eight days to reach the ISS, where it will provide more space for scientific experiments.
It had been due for launch in 2007 but was delayed due to numerous technical problems, including contamination in its fuel system in 2013.
It will now need various manoeuvres, including up to 11 spacewalks, before it is ready to be used.
The incident prompted NASA to postpone the 3 August test flight for a Boeing capsule from Florida.
Boeing was set to make its second attempt to reach the 250-mile-high ISS after software problems ruined the first test.
The ISS is currently being operated by NASA astronauts Mark Vande Hei, Shane Kimbrough and Megan McArthur; Oleg Novitsky and Pyotr Dubrov of Russia's Roscosmos; Japan Aerospace Exploration
Agency astronaut Akihiko Hoshide and European Space Agency astronaut Thomas Pesquet.
Reference: SKy Newd:
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