The Conversation

The amount of oxygen in the Earth's atmosphere makes it a habitable planet.Twenty-one per cent of the atmosphere consists of this life-giving element. But in the deep past — as far back as the Neoarchean era 2.8 to 2.5 billion years ago — this oxygen was almost absent. So, how did Earth's atmosphere...

Many users, fearing that Twitter will soon become a safe haven for far-right trolls and misinformation under Musk's free speech policy, have since found their way onto Mastodon.

Mastowhat? Mastodon, once a lesser-known social media platform used mostly by tech nerds, has been put in the spotlight during Musk's chaotic takeover of Twitter.

Picture the exact same kind of platform as Twitter, only fewer ads, fewer algorithms, and, alas, much fewer users.

Once you get past a little jargon at the beginning, it's not difficult to get up and running. Here's how it works and what it can do.

What's with the name?

Mastodons were primitive, elephant-like animals that became extinct around 10,000 years ago at the end of the Ice Age. That's why you won't see phrases like "tweet" from the so-called "bird app". On Mastodon, you "toot."

The idea for the name came from Eugen Rochko, who founded Mastodon in 2016 and has been developing it ever since, free of advertising and tracking. The entire software development is financed by donations.

What can Mastodon do?

Mastodon shares the same basic features as Twitter. You can follow others and see their posts, which are called toots, not tweets.

Just like on Twitter, you post short texts with attached pictures, videos, audio or polls. You can also limit who can see your tweets - ahem, toots.

The same goes for direct messages, hashtags and trending topics. You can also retweet other toots, only that here it's called "boosting". Like on Twitter, you can secure your account by adding two-factor authentication to your login, meaning you need to confirm logins on new devices.

Is it better than Twitter?

You'll have to decide that for yourself, of course, but advocates say there are two major benefits over Twitter - a timeline that isn't reordered by algorithms like on Twitter and a decentralised network that isn't controlled by one company.

First of all, your start page is where you can find posts from all the people or organisations you follow in chronological order. Mastodon strictly adheres to chronology.

That means there are real timelines, unlike Twitter's re-ordering of tweets as determined by algorithms designed to increase your interaction.

"Your home feed should be filled with what matters to you most, not what a corporation thinks you should see," reads the mission statement on the Mastodon page.

Secondly, Mastodon is also a decentralised social network, connected and powered by open source, free software. Whether it's for an organisation or a private user, anyone who wants to can run an independent Mastodon server. These are called "instances" and each one exists independently of other instances.

That means that control is not in the hands of one company - or one "free speech absolutist" billionaire oligarch - but in the hands of those who wants to participate on running the server.

It helps to know this before you sign up, since you'll need to pick an instance for your account. Many - but not all - instances focus on a topic of interest, be it LGBTQ+ issues, cloud computing or just a particular country or city.

Once you have signed up to an instance, you'll be able to see a feed of what everyone on that instance is tooting in the "local" view.

The "federation" view, on the other hand, broadens your perspective to all toots from all servers. Like the start page, the local and federation views are also organised as timelines.

Those leaving Twitter, meanwhile, may argue that it's biggest advantage is that it's not Twitter, a company recently decimated by tech tycoon Elon Musk in an effort to secure profitability, measures that some fear have undermined the company's long-term stability.

Meanwhile, Musk's push for free speech and amnesty for banned users, combined with a chaotic roll-out of blue ticks for cash, followed by fake accounts spoofing companies and celebrities, has worried many long-time users about a surge in far-right content and fake posts.

And is anything worse than on Twitter?

There's no denying that Mastodon doesn't come anywhere close to the scale of Twitter, and the vast majority of major celebrities and media organizations on Twitter have yet to make the jump.

While Mastodon does have many of the same features, the switch feels somewhat like moving from a buzzing city like New York to a small town in a different country.

While the absence of algorithm-based feed of toots has its benefits, it can make for rather dull scrolling depending on what accounts you follow.

One media account tooting a dozen or so stories can quickly clog your feed and drown out other potentially interesting toots you may have missed earlier in the day.

At the same time, social media nerds and news junkies may find themselves missing Tweetdeck, the advanced version of Twitter.

Ok I'm interested. Which server/instance should I sign up to?

First of all, it's important to know that no matter which one you choose, you'll always be able to see content on all the other servers and interact with all the other users. That's the purpose of the "federation" view.

However, every server operator can block other servers. And it can set rules that then apply to the users of its own server. So it makes sense to look for a community with which you can perhaps not only identify thematically, but whose moderation suits you overall.

Are there server directories?

Yes, a server directory can be found on the official Mastodon page. It only contains servers that consistently commit to moderating against racism, sexism and transphobia (https://joinmastodon.org/de/covenant).

Another possible starting point for your own Mastodon account is the page "Instances.social", which currently lists more than 3,700 servers worldwide. If you answer a few questions, you will be shown a list of servers that might suit you.

Although you can register directly with many servers, there are also instances where you first have to request an invitation, which no longer accept new members or which are basically closed.

Wait, what if I later find a community I like better?

No problem. You can have several accounts on different Mastodon servers at the same time. You can also move an existing account with your followers to a new account on another server at any time. Instructions can be found directly in the account settings or in the Mastodon documentation.

In the settings under "Import and Export" you can also download the other data categories (except media) in CSV format, such as lists or bookmarks. And not only to import them into the new account when you plan to move.

Regular backups are also a good idea in case the instance on which you are logged in is unexpectedly switched off. All data categories including media storage can be downloaded once a week as an archive.

So I've found the right instance - now what?

Selecting the server was already half the battle. Now you have to hit "Create account" on the page of your preferred instance, accept the respective server rules, enter an email address and specify both a display name and profile name (preceded by @).

The user name is extended with the name of the community domain so that communication and searches are possible across server boundaries (example: @profilname@community-name.com).

What are my first steps as a new user?

After registering, you'll need to complete your profile (picture, background, interests) and adjust notifications and privacy settings in the settings. For example, you can set it so that followers can only follow you after approval.

You can also specify that your own posts do not go into the public timeline by default. Nevertheless, when writing a post, you always have the option to make a different setting for this post individually using the lock symbol.

How can I find my Twitter contacts on Mastodon?

There are services like Fedifinder or Debirdify that can analyse your Twitter profile to see which contacts are also on Mastodon. This information is available as a list that can also be saved in CSV format and then imported into Mastodon.

If you plan on staying on Twitter for the time being, then it's not a bad idea to change your username to your Mastodon profile name. That way, every time you tweet, your followers see that you're on Mastodon and know how to find you.

For it to work, you need to enter the profile name and community domain, eg. "@profilname@community-name.org", not just "@profilname".

Are there also apps?

Yes. In addition to the web app and the official apps for Android and iOS, which have been available since April 2022, there are various third-party apps for different platforms and operating systems.

The amount of oxygen in the Earth's atmosphere makes it a habitable planet.Twenty-one per cent of the atmosphere consists of this life-giving element. But in the deep past — as far back as the Neoarchean era 2.8 to 2.5 billion years ago — this oxygen was almost absent. So, how did Earth's atmosphere become oxygenated? Our research, published in Nature Geoscience, adds a tantalizing new possibility: that at least some of the Earth's early oxygen came from a tectonic source via the movement and destruction of the Earth's crust.The Archean EarthThe Archean eon represents one third of our planet's history, from 2.5 billion years ago to four billion years ago. This alien Earth was a water-world, covered in green oceans, shrouded in a methane haze and completely lacking multi-cellular life. Another alien aspect of this world was the nature of its tectonic activity. On modern Earth, the dominant tectonic activity is called plate tectonics, where oceanic crust — the outermost layer of the Earth under the oceans — sinks into the Earth's mantle (the area between the Earth's crust and its core) at points of convergence called subduction zones. However, there is considerable debate over whether plate tectonics operated back in the Archean era. One feature of modern subduction zones is their association with oxidized magmas. These magmas are formed when oxidized sediments and bottom waters — cold, dense water near the ocean floor — are introduced into the Earth's mantle. This produces magmas with high oxygen and water contents. Our research aimed to test whether the absence of oxidized materials in Archean bottom waters and sediments could prevent the formation of oxidized magmas. The identification of such magmas in Neoarchean magmatic rocks could provide evidence that subduction and plate tectonics occurred 2.7 billion years ago.The experimentWe collected samples of 2750- to 2670-million-year-old granitoid rocks from across the Abitibi-Wawa subprovince of the Superior Province — the largest preserved Archean continent stretching over 2000 km from Winnipeg, Manitoba to far-eastern Quebec. This allowed us to investigate the level of oxidation of magmas generated across the Neoarchean era. The 2750- to 2670-million-year-old granitoid rocks collected from the largest preserved Archean continent may help reveal the origin story of the Earth's oxygen. (Dylan McKevitt), Author providedMeasuring the oxidation-state of these magmatic rocks — formed through the cooling and crystalization of magma or lava — is challenging. Post-crystallization events may have modified these rocks through later deformation, burial or heating.So, we decided to look at the mineral apatite which is present in the zircon crystals in these rocks. Zircon crystals can withstand the intense temperatures and pressures of the post-crystallization events. They retain clues about the environments in which they were originally formed and provide precise ages for the rocks themselves. Small apatite crystals that are less than 30 microns wide — the size of a human skin cell — are trapped in the zircon crystals. They contain sulfur. By measuring the amount of sulfur in apatite, we can establish whether the apatite grew from an oxidized magma. Map of the Superior Province that stretches from central Manitoba to eastern Quebec in Canada. (Xuyang Meng), Author providedWe were able to successfully measure the oxygen fugacity of the original Archean magma — which is essentially the amount of free oxygen in it — using a specialized technique called X-ray Absorption Near Edge Structure Spectroscopy (S-XANES) at the Advanced Photon Source synchrotron at Argonne National Laboratory in Illinois. Creating oxygen from water?We found that the magma sulfur content, which was initially around zero, increased to 2000 parts per million around 2705 million years. This indicated the magmas had become more sulfur-rich. Additionally, the predominance of S6+ — a type of sulfer ion — in the apatite suggested that the sulfur was from an oxidized source, matching the data from the host zircon crystals.These new findings indicate that oxidized magmas did form in the Neoarchean era 2.7 billion years ago. The data show that the lack of dissolved oxygen in the Archean ocean reservoirs did not prevent the formation of sulfur-rich, oxidized magmas in the subduction zones. The oxygen in these magmas must have come from another source, and was ultimately released into the atmosphere during volcanic eruptions.We found that the occurrence of these oxidized magmas correlates with major gold mineralization events in the Superior Province and Yilgarn Craton (Western Australia), demonstrating a connection between these oxygen-rich sources and global world-class ore deposit formation. The driving of ocean water deep into the Earth, caused by the sliding of oceanic plates under the Earth's continental plates, may generate free oxygen as well as the mechanism to release it — volcanoes. (Shutterstock)The implications of these oxidized magmas go beyond the understanding of early Earth geodynamics. Previously, it was thought unlikely that Archean magmas could be oxidized, when the ocean water and ocean floor rocks or sediments were not. While the exact mechanism is unclear, the occurrence of these magmas suggests that the process of subduction, where ocean water is taken hundreds of kilometres into our planet, generates free oxygen. This then oxidizes the overlying mantle. Our study shows that Archean subduction could have been a vital, unforeseen factor in the oxygenation of the Earth, the early whiffs of oxygen 2.7 billion years ago and also the Great Oxidation Event, which marked an increase in atmospheric oxygen by two per cent 2.45 to 2.32 billion years ago.As far as we know, the Earth is the only place in the solar system — past or present — with plate tectonics and active subduction. This suggests that this study could partly explain the lack of oxygen and, ultimately, life on the other rocky planets in the future as well.David Mole, Postdoctoral fellow, Earth Sciences, Laurentian University; Adam Charles Simon, Arthur F. Thurnau Professor, Earth & Environmental Sciences, University of Michigan, and Xuyang Meng, Postdoctoral Fellow, Earth and Environmental Sciences, University of MichiganThis article is republished from The Conversation under a Creative Commons license. Read the original article.

Where did the Earth's oxygen come from? New study hints at an unexpected source

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Scientists announced new findings about when Earth's oxygen 1st increased in the atmosphere. The results will help scientists search for life on other worlds.
The post Earth's oxygen provides new clues to alien life first appeared on EarthSky.

Earth's oxygen provides new clues to alien life

A new study may have found a missing link that helps explain the Earth's unique oxygen-rich atmosphere—and the evolution of animal life on the planet.

New theory may explain Earth's oxygen-rich atmosphere and the late evolution of animal life

Billions of years ago, crushed quartz reacting with water could have created the conditions needed for the evolution of the photosynthetic microbes responsible for most of the oxygen now in Earth's atmosphere

Oxygen on early Earth may have come from quartz crushed by earthquakes

Hydrogen and oxygen ions escaping from Earth's upper atmosphere and combining on the moon could be one of the sources of the known lunar water and ice, according to new research.

Earth's atmosphere may be source of some lunar water

Previous research purported that the basic building block of life appeared in our atmosphere roughly 2.5 billion years ago. A new study rejects that timeline.

Earth's First Whiff of Oxygen

Hydrogen and oxygen ions escaping from Earth's upper atmosphere and combining on the moon could be one of the sources of the known lunar water and ice, according to new research by University of Alaska Fairbanks Geophysical Institute scientists.