Signs of water plumes on Jupiter’s moon Europa suggest it might harbour life

Jupiter. Image: Getty.

Along with Mars, Jupiter’s moon Europa has long captured the imagination of science fiction writers as a potential place for life in the solar system beyond Earth. In science fact, missions have found hints of a subsurface water ocean below the icy crust of the moon. And where there’s warm, liquid water, and the right chemistry, there could indeed be life.

Finding out whether this is the case is not going to be easy though. One complicated and expensive solution would be landing on the moon and drilling a hole through the ice to sample the water beneath. But now research has thrown up a better option. The exciting results, published in Nature Astronomy, suggest there may be plumes emanating from Europa’s ocean – meaning a spacecraft could simply fly though them to test the water. The findings are important for the upcoming Europa Clipper missions and JUICE missions.

It’s not the first time it’s been suggested that there are geyser-like features on the moon. The Hubble Space Telescope saw transient signs of plumes from Europa’s subsurface ocean in 2012 and 2016. However, the result was controversial – the data was after all captured from far away (Hubble orbits the Earth). The new evidence instead comes from an actual flyby of Europa by the Galileo mission in 1997 – significantly strengthening the evidence that there are plumes on the moon.

We don’t know exactly how thick Europa’s ice shell is or how deep its subsurface ocean is. A 2011 study showed that there are locations where water may be relatively close to the surface in great lakes, near chopped up icy “chaos regions”, which are similar to some Antarctic structures on Earth.

Lessons from Enceladus

The Cassini mission to Saturn discovered huge plumes of water coming from the small moon Enceladus. The first hints were from magnetic field deflections and an abundance of charged particles in a certain region of the moon. We know that the dense gas of newly emerged molecules and atoms in a watery plume becomes charged (ionised) as electrons are knocked off. This makes it electrically conducting, causing changes to surrounding magnetic fields.

Enceladus’s south polar plumes, as seen by Cassini, 30 November 2010. Image: NASA/JPL-Caltech/Space Science Institute.

Next, the plumes were actually spotted in spectacular images, emanating from what looks like tiger stripes near the south pole. There is evidence from gravity measurements that the source is a subsurface ocean.

Cassini flew past Enceladus 22 times, enabling exploration of the plumes ejected directly from the ocean below. As well as simple water, ions and charged grains in the plumes, Cassini found sodium – a sign that the ocean is salty. It also found silicates, which indicate a sandy ocean floor and potentially the existence of hydrothermal vents.

This is important as chemical reactions between sand and water can provide enough energy in the water to feed microbial life (and tends to happen near hydrothermal vents on Earth). Finally, in 2107, Cassini also discovered hydrogen in the plumes, which should be a byproduct of such water-sand reactions. This is as close as you can get to a proof that it is a suitable candidate to host life.

Following these exciting discoveries, the hunt was on for plumes at Europa. Based on the Hubble measurements, estimates in 2012 showed that the amount of water released in the Europa plumes could be a factor 30 times that of Enceladus. The plumes appeared to have a height of some 200km. Like Enceladus, the floor of Europa’s ocean is likely in contact with sand and rock. This is in contrast to some other moons with subsurface oceans – including Ganymede and Callisto – where the ocean floor is ice.

In the new study, magnetometer data from a Galileo flyby less than 400km above Europa’s icy surface was reexamined and compared with a modern computer model of how charged gas on Europa should behave. The results – based on an observed deflection and decrease in the observed magnetic field over a distance of 1,000km – imply that there’s a dense region of charged particles. This is very likely to be the result of a plume, making it the best direct evidence for such an occurence yet.

Upcoming missions

As with Enceladus, the Europa plumes offer the tantalising prospect of directly sampling material from the subsurface ocean. Two future missions will be able to explore this. The European Space Agency’s JUICE mission, which I am involved in developing, is due to launch in 2022 and will arrive in the Jupiter system on 2030. Two close flybys of Europa are planned as part of a sequence, before going into orbit around the moon Ganymede in 2032.

NASA’s Europa Clipper will perform 45 flybys of Europa. Both these missions can explore the plumes in the same way the Cassini orbiter did at Enceladus. Following these, landers or penetrators at Europa have been proposed (but yet to secure funding). In the meantime, sampling the plumes could provide many exciting insights into what’s going on in the ocean. If we are really lucky we may even be able to detect signatures of biological activity. Unfortunately, Cassini was not equipped to look for such signatures at Enceladus.

Image: NASA/JPL-Caltech/SETI Institute.

This means there are now four likely locations for life beyond Earth in our solar systems. First Mars, where conditions were right for life to form 3.8bn years ago. We will explore this further with the ExoMars 2020 rover, which I am also involved in developing. This will be able to drill up to two metres underneath the surface to search for biomarkers, as well as the NASA Mars 2020 rover and the related helicopter recently announced.

But on Europa and Enceladus there could actually be life now, and sampling the plumes will help reveal whether this is the case. At Saturn’s moon Titan, we have also found signs of complex prebiotic chemistry that once gave rise to life on Earth. This means it is a location for future or perhaps current life.

As well as the planned missions to Mars and Europa, it is therefore also important that we also return to the Saturn system to track down where there may be life elsewhere. NASA’s Dragonfly quadcopter proposed for Titan is one possibility.

The ConversationWith so many promising candidates for life in our own solar system, it is exciting to think that it could be just a few years until we discover some form of microbial alien life.

Andrew Coates, Professor of Physics, Deputy Director (Solar System) at the Mullard Space Science Laboratory, UCL.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

British television once sounded like Britain. But then, the ITV mergers happened

The Granada Studios, Quay Street, Manchester. Image: Wikimedia Commons.

This summer, several ITV franchises celebrated half a century of continuous operation. There was a Yorkshire Television themed cake, and a flag bearing the company’s logo was flown over ITV’s Yorkshire base for a time. It was all very jolly – but while a few people beyond Britain’s small community of television historians and old telly nerds engaged with the idea, any excitement was brief.

The main reason for is not, as you might assume, that, in the era of streaming and so forth, ITV is no longer a dominant presence in many people’s cultural lives: even the quickest of glances at the relevant figures would tell you otherwise. No, it’s because the mere existence of ITV’s franchises is now passing out of common memory. They are the trademarks, literally rather than figuratively, of a version of ITV that today exists only nominally.

For most of its history, ITV operated on a federal model. ITV wasn’t a company, it was a concept: ‘Independent Television’, that is, television which was not the BBC.

It was also a network, rather than a channel – a network of multiple regional channels, each of which served a specific area of the UK. Each had their own name and onscreen identity; and each made programmes within their own region. They were ITV – but they were also Yorkshire, Granada, Grampian, Thames, and so on.

So when I was a child growing up the in Midlands in the ‘80s, no one at school ever said “ITV”: they said “Central”, because that’s what the channel called itself on air, or “Channel Three” because that’s where it was on the dial. To visit friends who lived in other regions was to go abroad – to visit strange lands where the third channel was called Anglia, and its logo was a bafflingly long film sequence of a model knight rotating on a record turntable, where all the newsreaders were different and where they didn’t show old horror films on Friday nights.

The ITV regions as of 1982, plus Ireland. Image: Wikimedia Commons.

Of course, there were programmes that were shown across the whole network. Any station, no matter in what part of the country, would be foolish not to transmit Coronation Street during the period where it could persuade nearly half the population to tune in. But even The Street wasn’t networked from the beginning: it started in six of the then eight ITV regions, and rolled out to the other two after a few months when it became clear the series was here to stay.

This was a common occurrence: The Avengers, one of the few ITV series to genuinely break America, began in an even more limited number of regions in the same year, with other areas scrambling to catch up when the programme became a hit.

The idea behind ITV’s structure was that the regions would compete with each other to put programmes on the network, opting in and out of others’ productions as worked best for them. ITV was, after all, an invention of a 1950s Conservative government that was developing a taste for the idea of ‘healthy competition’ even as it accepted the moral and practical case for a mixed economy. The system worked well for decades: in 1971, for example, the success of London Weekend Television’s Upstairs, Downstairs, creatively and commercially, and domestically and internationally, prompted other regions to invest in high end period dramas so as to not look like a poor relation.


Even away from prestige productions there was, inexplicable as it now seems, a genuine sense of local pride when a hit programme came from your region. That Bullseye was made on Broad Street in Birmingham was something that people knew. That 17.6m people watched the 1984 Xmas special, making it one of the ten most watched programmes of the year, made Bully a sort of local hero. In more concrete terms, Bullseye and other Birmingham based programmes provided jobs, and kept that part of the country visible from all others. This was true of all areas, and from all areas.

ITV franchises would often make programmes that were distinctive to, or set in, their region. Another of Central’s late eighties hits was Boon. It might have starred the cockney-sounding Michael Elphick, but it was filmed and set in Birmingham, just as Central’s predecessor ATV’s Public Eye had been at the end of the sixties. In Tales of the Unexpected, one of the poorest and smallest ITV regions, the aforementioned Anglia, made a bona fide international hit, largely filmed in transmission area, too. HTV produced a string of children’s series set in its south west catchment area, including some, such as The Georgian House, that examined the way the area had profited from the slave trade.

There was another element of ‘competition’ in the structure of ITV as originally conceived: the franchises were not for life. Every few years, a franchise round would come along, forcing the incumbent stations to bid to continue its own existence against other local offerings.

The process was no simple auction. Ministers were empowered to reject higher financial bids if they felt a lower bid offered other things that mattered: local employment or investment, programming plans that reflected the identity of the region they were bidding to serve, or simply higher quality programmes.

Yorkshire Television itself owes its existence to just such a franchise round: the one that followed a 1967 decision by regulator IBA that Granada, until then the holder of a pan-northern England licence, was insufficiently local to Yorkshire. For a decade, commissioning and production had been concentrated in Manchester, with little representation of, or benefit for, the other side of the Pennines. IBA’s decision was intended to correct this.

Yorkshire existed in practical terms for almost exactly 40 years. Its achievements included Rising Damp, the only truly great sitcom ever made for ITV.

But in 1997 it was, ironically, bought out by Granada, the company who had had to move aside in order for it to be created. What had changed? The law.

In 1990, another Conservative government, one even keener on competition and rather less convinced of the moral and practical case for a mixed economy, had changed the rules concerning ITV regions. There was still a ‘quality threshold’ of a sort – but there was less discretion for those awarding the franchises. Crucially, the rules had been liberalised, and the various ITV franchises that existed as of 1992 started buying out, merging with and swallowing one another until, in 2004, the last two merged to form ITV plc: a single company and a single channel.

The Yorkshire Television birthday cake. Image: ITV.

Yorkshire Television – or rather ITV Yorkshire as it was renamed in 2006 – is listed at Companies House as a dormant company, although it is still the nominal holder of the ITV licence for much of Northern England. Its distinctive onscreen identity, including the logo, visible on the cake above, disappeared early this century, replaced by generic ITV branding, sometimes with the word Yorkshire hidden underneath it, but often without it. Having once been created because Manchester was too far away, Yorkshire TV is now largely indistinguishable from that offered in London. (It is more by accident of history than anything else that ITV retains any non-London focus at all; one of the last two regions standing was Granada.)

The onscreen identities of the all the other franchises disappeared at roughly the same time. What remained of local production and commissioning followed. Regional variations now only really exist for news and advertising. TV is proud that is can offer advertisers a variety of levels of engagement, from micro regional to national: it just doesn’t bother doing so with programming or workforce any more.

Except for viewers in Scotland. Curiously, STV is an ITV franchise which, for reasons too complicated to go into here, doesn’t suffer from the restrictions/opportunities imposed by upon its English brethren in 1990. It also – like UTV in Northern Ireland, another complex, special case – Its own onscreen identity. Nationalism, as it so often does, is trumping regionalism – although it was not all that long ago that Scotland had multiple ITV regions, in recognising its own lack homogeneity and distinct regions, while respecting its status as a country.


As is often observed by anyone who has thought about it for more than four seconds, the UK is an almost hilariously over-centralised country, with its political, financial, administrative, artistic and political centres all in the same place. Regionalised television helped form a bulwark against the consequences of that centralisation. Regional commissioning and production guaranteed that the UK of ITV looked and sounded like the whole of the UK. The regions could talk about themselves, to themselves and others, via the medium of national television.

The idea of a federal UK crops up with increasing frequency these days; it is almost inconceivable that considerable constitutional tinkering will not be required after the good ship UK hits the iceberg that is Brexit, and that’s assuming that Northern Ireland and Scotland remain within that country at all. If the UK is to become a federation, and many think it will have to, then why shouldn’t its most popular and influential medium?

A new Broadcasting Act is needed. One that breaks up ITV plc and offers its constituent licences out to tender again; one that offers them only on the guarantee that certain conditions, to do with regional employment and production, regional commissioning and investment, are met.

Our current national conversation is undeniably toxic. Maybe increasing the variety of accents in that conversation will help.

Thanks to Dr David Rolinson at the University of Stirling and britishtelevisiondrama.org.uk.