Watch: this is what Mars looked like 3.7 billion years ago

While it seems to be a dead planet today, in the past the Red Planet would have felt very much like home to us - with clouds, oceans and blue sky.

We are nearly as certain as it is scientifically possible to be that there isn't any life on Mars. There is still every chance that there was life at some point, and we might still find it. The landscape is clearly marked with signs of water erosions, and Curiosity and Opportunity (the two rovers currently trundling around up there) have taught us a huge deal about its geology - including the discovery of "abundant" traces of water in Martian soil. Mars clearly had a lot of liquid water on its surface at some point.

The question, though, is why it doesn't have lakes, rivers, oceans, and streams any more - and what it looked like when it did. Nasa's Goddard Space Flight Center has taken a stab at visualising the Martian world of 3.7 billion years ago ahead of its Mars Atmosphere and Volatile Evolution (or Maven) mission which takes off on 18 November, producing a quite lovely animation:

It looks just like Earth because back then Mars had two Earth-like things going for it that it doesn't any more. Firstly, the habitable zone around the younger, larger Sun - that's the range of orbits around any star within which is neither too hot nor too cold for a planet to have liquid water on its surface - was further out, and secondly Mars also had a thick atmosphere. Without the pressure that comes with an atmosphere, liquid water will either freeze solid or evaporate instantly, as happens currently on Mars.

The habitable zone moving inwards had the happy side effect of making the Earth habitable, and eventually - as the Sun enters its final few billion years and swells in size, becoming a red giant - that zone may well move out further again and give Mars a chance at hosting liquid water again. That is, if it gets an atmosphere too, and that's the mystery. We know it must have been there once, but it isn't there now, and we can't be sure why that it. We're not even totally sure if the atmosphere's disappearance is wholly responsible for the transformation of Mars from wet, blue globe like you see above to dusty, red ball that looks like this:

That's a picture taken by the Curiosity rover.
Credit: NASA/JPL-Caltech/MSSS

One possibility for what happened to the atmosphere is that Mars' core cooled down and stopped generating both plate tectonics and a magnetic field, which would have formed a barrier that would have stopped too many atmospheric particles being stripped away into space by the solar wind. Without active volcanoes to generate gases to replace the lost particles, you end up with the situation today where the surface pressure on Mars is, on average, 0.6 percent that of what you'll find on Earth. That's equivalent to being 35km up in the sky on Earth, nearly twice as high as where commercial aeroliners fly.

Maven is an orbiting probe that will launch on 18 November and try to uncover more data about Mars' atmospheric past. Here's Joseph Grebowsky, the mission's project scientist:

Studies of the remnant magnetic field distributions measured by Nasa's Mars Global Surveyor mission set the disappearance of the planet's convection-produced global magnetic field at about 3.7 billion years ago, leaving the Red Planet vulnerable to the solar wind. 

Maven has been designed to measure the escape rates for all the applicable processes and will be able to single out the most prominent. Previous remote Mars observations from orbiting spacecraft have observed the geological features that have been used to estimate the amount of water that did exist and have analysed the global distribution of water ice and surface chemistry to infer that water was lost through time. Mars Curiosity rover has the ability to analyse the chemical composition of the solid surface, which contains information of the atmospheric composition during the formation of the planet, in particular the isotope ratios, the lower atmosphere composition, and the current gas exchange with surface reservoirs. MAVEN is going to measure the current rates of loss to space and the controlling processes. Given the lower-atmosphere information and the nature of the escaping processes, one can extrapolate from current conditions into the climate of the past.

The probe will reach Mars in September 2014, and is scheduled to work for one Earth year on its mission of uncovering more Martian secrets.

Not Earth, but Mars before it lost its atmosphere. (Image: Nasa)

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

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Fark.com’s censorship story is a striking insight into Google’s unchecked power

The founder of the community-driven website claims its advertising revenue was cut off for five weeks.

When Microsoft launched its new search engine Bing in 2009, it wasted no time in trying to get the word out. By striking a deal with the producers of the American teen drama Gossip Girl, it made a range of beautiful characters utter the words “Bing it!” in a way that fell clumsily on the audience’s ears. By the early Noughties, “search it” had already been universally replaced by the words “Google it”, a phrase that had become so ubiquitous that anything else sounded odd.

A screenshot from Gossip Girl, via ildarabbit.wordpress.com

Like Hoover and Tupperware before it, Google’s brand name has now become a generic term.

Yet only recently have concerns about Google’s pervasiveness received mainstream attention. Last month, The Observer ran a story about Google’s auto-fill pulling up the suggested question of “Are Jews evil?” and giving hate speech prominence in the first page of search results. Within a day, Google had altered the autocomplete results.

Though the company’s response may seem promising, it is important to remember that Google isn’t just a search engine (Google’s parent company, Alphabet, has too many subdivisions to mention). Google AdSense is an online advertising service that allows many websites to profit from hosting advertisements on its pages, including the New Statesman itself. Yesterday, Drew Curtis, the founder of the internet news aggregator Fark.com, shared a story about his experiences with the service.

Under the headline “Google farked us over”, Curtis wrote:

“This past October we suffered a huge financial hit because Google mistakenly identified an image that was posted in our comments section over half a decade ago as an underage adult image – which is a felony by the way. Our ads were turned off for almost five weeks – completely and totally their mistake – and they refuse to make it right.”

The image was of a fully-clothed actress who was an adult at the time, yet Curtis claims Google flagged it because of “a small pedo bear logo” – a meme used to mock paedophiles online. More troubling than Google’s decision, however, is the difficulty that Curtis had contacting the company and resolving the issue, a process which he claims took five weeks. He wrote:

“During this five week period where our ads were shut off, every single interaction with Google Policy took between one to five days. One example: Google Policy told us they shut our ads off due to an image. Without telling us where it was. When I immediately responded and asked them where it was, the response took three more days.”

Curtis claims that other sites have had these issues but are too afraid of Google to speak out publicly. A Google spokesperson says: "We constantly review publishers for compliance with our AdSense policies and take action in the event of violations. If publishers want to appeal or learn more about actions taken with respect to their account, they can find information at the help centre here.”

Fark.com has lost revenue because of Google’s decision, according to Curtis, who sent out a plea for new subscribers to help it “get back on track”. It is easy to see how a smaller website could have been ruined in a similar scenario.


The offending image, via Fark

Google’s decision was not sinister, and it is obviously important that it tackles things that violate its policies. The lack of transparency around such decisions, and the difficulty getting in touch with Google, are troubling, however, as much of the media relies on the AdSense service to exist.

Even if Google doesn’t actively abuse this power, it is disturbing that it has the means by which to strangle any online publication, and worrying that smaller organisations can have problems getting in contact with it to solve any issues. In light of the recent news about Google's search results, the picture painted becomes more even troubling.

Update, 13/01/17:

Another Google spokesperson got in touch to provide the following statement: “We have an existing set of publisher policies that govern where Google ads may be placed in order to protect users from harmful, misleading or inappropriate content.  We enforce these policies vigorously, and taking action may include suspending ads on their site. Publishers can appeal these actions.”

Amelia Tait is a technology and digital culture writer at the New Statesman.