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Why the moon’s early magnetic field might be responsible for life on earth

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The habitability of a planet depends on many factors. One is the existence of a strong and long-lived magnetic field. These fields are generated thousands of kilometers below the planet’s surface in its liquid core and extend far into space – shielding the atmosphere from harmful solar radiation.

Without a strong magnetic field, a planet struggles to hang on to a breathable atmosphere – which is bad news for life as we know it. A new study, published in Science Advances, suggests that the Moon’s now extinct magnetic field may have helped protect our planet’s atmosphere as life was forming around 4 billion years ago.

Today, Earth has a strong global magnetic field that protects the atmosphere and low-orbiting satellites from harsh solar radiation. In contrast, the Moon does not possess either a breathable atmosphere or a global magnetic field.

Global magnetic fields are generated by the motion of molten iron in the cores of planets and moons. Keeping the fluid moving requires energy, such as heat trapped within the core. When there is insufficient energy, the field dies.

Without a global magnetic field, the charged particles of the solar wind (radiation from the Sun) passing close to a planet generate electric fields that can accelerate charged atoms, known as ions, out of the atmosphere. This process is happening today on Mars and it is losing oxygen as a result – something that has been directly measured by the Mars atmosphere and volatile evolution (Maven) mission. The solar wind can also collide with the atmosphere and knock molecules into space.

The Maven team estimates that the amount of oxygen lost from the Martian atmosphere throughout its history is equivalent to that contained in a global layer of water, 23 meters thick.

[Read: The Moon’s surface is rusting — and Earth may be to blame]

Probing ancient magnetic fields

The new research investigates how the Earth’s and Moon’s early fields may have interacted. But probing these ancient fields isn’t easy. Scientists rely on ancient rocks that contain small grains that got magnetized as the rocks formed, saving the direction and strength of the magnetic field at that time and place. Such rocks are rare and extracting their magnetic signal requires careful and delicate laboratory measurement.

A picture of the ancient moon with magnetic field lines.
Our Moon, four billion years ago generated its own magnetic field. NASA

Such studies have, however, unveiled that Earth has generated a magnetic field for at least the last 3.5 billion years, and possibly as far back as 4.2 billion years, with a mean strength just over half of the present-day value. We don’t know much about how the field was behaving any earlier than that.

By contrast, the Moon’s field was perhaps even stronger than Earth’s around 4 billion years ago, before precipitously declining to a weak field state by 3.2 billion years ago. At present, little is known about the structure or time-variability of these ancient fields, though.

Another complexity is the interaction between the early lunar and geomagnetic fields. The new paper, which modeled the interaction of two magnetic fields with north poles either aligned or the opposite, shows that the interaction extends the region of near-Earth space between our planet and the Sun that is shielded from the solar wind.

The new study is an interesting first step towards understanding how important such effects would be when averaged over a lunar orbit or the hundreds of millions of years that are important for assessing planetary habitability. But to know for sure we need further modelling and more measurements of the strengths of the Earth and Moon’s early magnetic fields.

What’s more, a strong magnetic field does not guarantee the continued habitability of a planet’s atmosphere – its surface and deep interior environments matter too, as do influences from space. For example, the brightness and activity of the Sun has evolved over billions of years and so has the ability of the solar wind to strip atmospheres.

How each of these factors contributes to the evolution of planetary habitability, and hence life, is still not fully understood. Their nature and how they interact with each other are also likely to change over geological timescales. But thankfully, the latest study has added another piece to an already fascinating puzzle.The Conversation

This article is republished from The Conversation by Christopher Davies, Associate Professor in Theoretical Geophysics, University of Leeds and Jon Mound, Associate Professor of Geophysics, University of Leeds under a Creative Commons license. Read the original article.

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PSA: Your new iPhone 12 or 12 Pro might need need contact tracing re-enabled

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Getting a new phone is exciting, but it can also lead to spending an annoying amount of time adjusting settings, permissions and notifications for all your apps. Cloud backups are supposed to make this process easier, but they don’t always catch everything – for instance, you’ll want to double-check that COVID-19 exposure notifications are still enabled on your new iPhone 12 if you restored from a backup. They might not be, according to BBC News.

If you’re concerned you might be affected, you can re-enable exposure notifications in iOS by opening the Settings app, selecting Exposure Notifications, and clicking “Turn On Exposure Notifications.”

Users first noticed issues with the official National Health Service (NHS) contact tracing app in the UK. When some iPhone 12 and 12 Pro owners tried to open the app after restoring an earlier iPhone backup, they were presented with an error message. Deleting and redownloading the app seemed to solve the problem by prompted the users to re-enable COVID-19 exposure notifications — but also deleted all the locations the users had previously checked into.

It’s not clear if this issue is exclusive to iPhone 12 models or if restoring any iPhone from a backup might turn off the setting: we’re asking Apple and will update you with what we hear. When we restored one of our own iPhone 12 phones from a backup, we did notice exposure notifications were turned off — so we suspect the issue might be at a system level rather than with specific apps like NHS.

The exposure notification system was originally announced in April and uses your phone’s Bluetooth to let you know if you’ve come in contact with someone who’s tested positive for COVID-19. The resulting notification can also direct you to up-to-date COVID-19 information online and where you can schedule a test for yourself.

Contact tracing, whether automatic or conducted manually, is not a magic bullet to get COVID-19 outbreaks under control. But it is one of many steps, including a robust and easily accessible testing program, that can help you find out if you’ve been infected sooner so that you don’t contribute to the spread. Re-enabling these notifications is a low effort way – along with wearing masks and washing your hands – to keep people out of harm’s way.

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Samsung’s original Galaxy Fold adds some of the Z Fold 2’s smartest features for free

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One of the Samsung Galaxy Z Fold 2’s coolest new features was the ability to use the phone’s front display as a viewfinder for the back cameras, which could be really useful for things lining up higher-quality selfies. If you’ve wanted that handy way to take better selfies but have been holding on to the original Galaxy Fold, you’re in luck: Samsung is bringing that selfie functionality and a number of other features from the Z Fold 2 to the first Fold through a software update that’s available starting today.

Samsung will let you use the front screen as a viewfinder for the Fold’s back cameras.
Image: Samsung

The Fold isn’t just getting a new way to take selfies. The update also brings Capture View Mode, which lets you frame a photo with one half of the Fold’s main screen and review up to five of the latest photos or videos you’ve taken on the other half. And Pro Video mode will now let you capture video in a 21:9 aspect ratio and at 24 fps.

The original Fold also gets a few features from the Z Fold 2 intended to improve productivity. App Pair, for example, lets you set a shortcut to launch up to three apps at once in your preferred split-screen layout. That means that if you like to have Twitter open on one half of your screen and YouTube on the other, you can make a shortcut to launch those apps together and set up the way you like them. You now can arrange split-screen windows horizontally, too,

Samsung’s blog notes that the launch date and the features included with the update “may vary by carrier or market,” however, so the update may not be available for your Fold just yet. Samsung tells The Verge it’s looking into when the update will be available in the US.

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Gillmor Gang: Unsuppressed

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[embedded content]

Not just the future of civilization is up for grabs this November. In this age of mobile social computing, we’re figuring out how to vote, entertain, teach, learn, and commit to meaningful change. Thanks to the pandemic emergency, our plans for transforming our country and planet are subject to immediate recall.

Much of the current political dynamic is expressed through the lense of “how much change can we afford to make?” The swing states in the race for the electoral college are those most profoundly affected by the transition from fossil fuel to renewable energy. The choice: how many jobs will we lose by shifting away from oil and gas to wind and solar. Workers in Pennsylvania, Ohio, Texas, and Michigan are fearful of losing their livelihood to a future of retraining and disruption.

Regardless of where we sit along the left/right spectrum, we share the increasing understanding that government doesn’t work. Running for office is a gauntlet of fundraising and promises you can’t keep; legislating is a lobbyist playground where special interests are neither special nor in our interests. The courts are overwhelmed by political power plays timed to inflame and suppress voting turnout. It’s no wonder that the common reaction to this week’s final presidential debate was relief that the campaign is almost over.

The most important fix to the body politic is the mute button. For a brief moment in the debate, we got to experience a few seconds of not talking. Time seemed to stand still, as if we were being handed down a digital tablet of things to not do: don’t interrupt, don’t disrespect, don’t mock, don’t waste our time. Above all, don’t forget the people we’ve lost to the virus. Remember the days when our biggest problems were what show to watch, what music to play, what jokes to tell. It’s amazing what you can hear when the agenda is turned back to ourselves.

In that moment, you can hear things that smooth the soul. In that moment, you can hear the words leaders will have to speak to get our vote next time. I feel much better about the next election no matter how this one turns out. The explosive numbers of early voting tell us a lot about how this will go. The genie is out of the bottle and people are beginning to connect the dots. If the vote is suppressed, it only makes us try harder.

Mobility is about a return to value, to roots, to resilience. Working from home is a big step toward living from everywhere. AR stands for accelerated reality, VR for valued reality. If we want to know what social is good for, switch on the mute button and listen to what you’ve lost. If you can mute the sound, you can unmute it and find your voice.

At first, the mute button was a defensive move. It counteracted the business model of the cable news networks, the repetitive time-filling of partisan perspective mixed with not listening to the grievances of the other side. The hardest thing I’ve had to do is be open to the truth emanating from the least likely location. We are taught to attack our opponent’s weaknesses; a better strategy might be to respect their strengths and adopt them as your own. Don’t worry, though. You probably won’t find too much there to reflect.

Once you experience the mute button envelope, you can hear it even if it’s not there. The rules of the revised debate were that the first two minutes of each candidate’s response used the mute button, then the old rules returned. Even then, the experience of using the mute button informed the rest of the debate. Particularly noticeable was Joe Biden’s response to a series of back and forths when the moderator asked if he had any further response. “… … … No.”

There have been other mute buttons in history. The 18 and a half minute gap spoke loudly when Rose Mary Woods erased a crucial Watergate tape. Before that, we assumed there might be a smoking gun. After that, we knew there might be others, too. Throughout the campaign, we could learn more about what was really going on by listening for the moments when key questions were left unanswered, ducked, or bounced back to the opponent like some Pee Wee Herman playground retort.

Soon we’ll know the answer to the important question: how do we confront the virus? I vote for listening to the science, wearing a mask, socially distancing both off and online, rapid testing, and contact tracing. And the candidates who agree.

__________________

The Gillmor Gang — Frank Radice, Michael Markman, Keith Teare, Denis Pombriant, Brent Leary, and Steve Gillmor . Recorded live Friday, October 23, 2020.

Produced and directed by Tina Chase Gillmor @tinagillmor

@fradice, @mickeleh, @denispombriant, @kteare, @brentleary, @stevegillmor, @gillmorgang

For more, subscribe to the Gillmor Gang Newsletter and join the backchannel here on Telegram.

The Gillmor Gang on Facebook … and here’s our sister show G3 on Facebook.

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