NASA Space Assets Detect Ocean inside Saturn Moon 

From NASA

April 3, 2014

NASA's Cassini spacecraft and Deep Space Network have uncovered evidence Saturn's moon Enceladus harbors a large underground ocean of liquid water, furthering scientific interest in the moon as a potential home to extraterrestrial microbes.

Researchers theorized the presence of an interior reservoir of water in 2005 when Cassini discovered water vapor and ice spewing from vents near the moon's south pole. The new data provide the first geophysical measurements of the internal structure of Enceladus, consistent with the existence of a hidden ocean inside the moon. Findings from the gravity measurements are in the Friday April 4 edition of the journal Science.

"The way we deduce gravity variations is a concept in physics called the Doppler Effect, the same principle used with a speed-measuring radar gun," said Sami Asmar of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., a coauthor of the paper. "As the spacecraft flies by Enceladus, its velocity is perturbed by an amount that depends on variations in the gravity field that we're trying to measure. We see the change in velocity as a change in radio frequency, received at our ground stations here all the way across the solar system."

The gravity measurements suggest a large, possibly regional, ocean about 6 miles (10 kilometers) deep, beneath an ice shell about 19 to 25 miles (30 to 40 kilometers) thick. The subsurface ocean evidence supports the inclusion of Enceladus among the most likely places in our solar system to host microbial life. Before Cassini reached Saturn in July 2004, no version of that short list included this icy moon, barely 300 miles (500 kilometers) in diameter.

"This then provides one possible story to explain why water is gushing out of these fractures we see at the south pole," said David Stevenson of the California Institute of Technology, Pasadena, one of the paper's co-authors.

Cassini has flown near Enceladus 19 times. Three flybys, from 2010 to 2012, yielded precise trajectory measurements. The gravitational tug of a planetary body, such as Enceladus, alters a spacecraft's flight path. Variations in the gravity field, such as those caused by mountains on the surface or differences in underground composition, can be detected as changes in the spacecraft's velocity, measured from Earth.

The technique of analyzing a radio signal between Cassini and the Deep Space Network can detect changes in velocity as small as less than one foot per hour (90 microns per second). With this precision, the flyby data yielded evidence of a zone inside the southern end of the moon with higher density than other portions of the interior.

The south pole area has a surface depression that causes a dip in the local tug of gravity. However, the magnitude of the dip is less than expected given the size of the depression, leading researchers to conclude the depression's effect is partially offset by a high-density feature in the region, beneath the surface.

"The Cassini gravity measurements show a negative gravity anomaly at the south pole that however is not as large as expected from the deep depression detected by the onboard camera," said the paper's lead author, Luciano Iess of Sapienza University of Rome. "Hence the conclusion that there must be a denser material at depth that compensates the missing mass: very likely liquid water, which is seven percent denser than ice. The magnitude of the anomaly gave us the size of the water reservoir."
There is no certainty the subsurface ocean supplies the water plume spraying out of surface fractures near the south pole of Enceladus, however, scientists reason it is a real possibility. The fractures may lead down to a part of the moon that is tidally heated by the moon's repeated flexing, as it follows an eccentric orbit around Saturn.

Much of the excitement about the Cassini mission's discovery of the Enceladus water plume stems from the possibility that it originates from a wet environment that could be a favorable environment for microbial life.

"Material from Enceladus’ south polar jets contains salty water and organic molecules, the basic chemical ingredients for life," said Linda Spilker, Cassini's project scientist at JPL. "Their discovery expanded our view of the 'habitable zone' within our solar system and in planetary systems of other stars. This new validation that an ocean of water underlies the jets furthers understanding about this intriguing environment."

[Old news but still excellent news. An ocean of any size, and I’m guessing that this one is going to be huge, is a valuable multi-niche environment that has endless possibilities for life. A chemical soup, even under miles of ice, left to its own devices for countless millions of years (most probably) has had plenty of time and opportunity to get very creative. Personally I would be overjoyed if they just found the predicted microbes but I’m guessing that there’s probably much more down there. I don’t see any reason why higher life forms couldn’t have evolved. After all we have the weird and wonderful creatures at the bottom of our own oceans to go by and guide us as to what’s possible in the dark depths. I’d be very surprised if we don’t find actual fish down there. If we found completely alien aquatic animals – completely divorced from anything here on Earth then the possibilities for life on far flung worlds becomes a practical certainty in my mind. Let’s hope that they can get a submersible mission to Enceladus soon and go fishing!]

Name to a Face?

Just Finished Reading: The Little Old Lady Who Broke All the Rules by Catharina Ingelman-Sundberg (FP: 2012)

When the austerity measures began to bite, especially when the daily cups of coffee dropped to two and pastries withdrawn altogether, it was the final straw for Martha Andersson. From that point on revolution was in the air. But she couldn’t do it alone. Any good conspiracy needs conspirators and Martha was lucky to have some close at hand – very close as they all lived in the same retirement home in Stockholm. What they needed was money, lots of it and fast. The only way to do that, a constant refrain from her extensive reading of crime novels reminded her, was to plan a brilliant robbery, so that it was she’d do. Escaping the retirement home thanks to the temporary theft of the buildings master key the newly formed League of Pensioners plan their first heist which nets very little. But practice makes perfect and their next crime will be sensational. Next door to their hotel is a world famous art gallery with some of the most expensive paintings in the world housed within. Carefully the case the building and select a pair of paintings that can be hidden by their Zimmer frames and those they are able to lift off the wall without too much upper body strength. The police are baffled having expected career criminals and fast cars rather than 79 year old Martha and her friends as they hobble out of the gallery on their way back to their expensive hotel room. Flushed by their success they demand a huge ransom for the return of the paintings fully expecting to get caught in the act and be sent to a much more comfortable prison than their increasingly uncomfortable retirement home. But, as with even the best plans things don’t quite turn out the way they’d hoped. With the police as a loose end it looks like the League will get away with their crime. The only question is what they’ll do with all that money – if they can lift the bags of cash onto their trolleys and make a leisurely get-away.

I think I picked this up in my local supermarket because it looked like it was fun and different. It certainly was both. Told with a wry sense of humour (you could almost see the author writing this with a continual smile on her face) this was amusing and somewhat sweet rather than laugh out loud funny – though it did make me do that a few times. All of the main protagonists from the retirement home, even the slightly annoying ones, grew on you (Martha herself was excellent and I’d love to have someone like that as an aging Aunt I could laugh with). The crimes themselves were well thought out and actually plausible – after a fashion. There was even a few tense moments when the League came up against ‘real’ criminals who threatened to overturn their plans and even do them some harm. The police did turn out to be rather silly which I couldn’t help finding a bit annoying but it was very much a minor annoyance. It did take a bit to get started but then so did the old dears before they started eating properly and taking gentle exercise. I was highly amused by one of the Leagues children (in their 40’s) who not only admired their mother’s renewed love of life and daring but actually helped the League in some of their later endeavours (without giving too much away.

Written with obviously a lot of love for the characters as well as more than a sprinkle of anger at the way older people are treated today, this was a delightfully different crime novel that turned out to be part comedy and part a heart-warming tale of pensioners who can do things for themselves. Recommended if you want a gentle read that will leave you smiling for days afterwards.

Translated from the Swedish by Rod Bradbury

 [2015 Reading Challenge: A funny book – COMPLETE (30/50)]

Cartoon Time.

Name to a Face?

My Favourite Movies: A Night to Remember (1958)

After completing an excellent book on the sinking of the Titanic I felt the urge to re-watch this classic British movie. Based largely on the classic book by Walter Lord and advised by some of the survivors this tells a pretty accurate account of what happened on that fateful night in 1912.

Of course being the kind of movie it was I can easily lay the blame of liking it so much at the feet of my father who introduced me to it and to one of his (and later my) favourite actors – Kenneth More who played 2nd Officer Lightoller. The story is, of course, about the ship, its maiden voyage across the Atlantic towards New York, the iceberg (dead ahead!), the inevitable foundering and great loss of life (not equalled for 70 years). The shock that reverberated across the world matched the hubris – so it’s said – of man claiming his conquest of nature by building an ‘unsinkable’ ship. Such a claim is made throughout the film though (I believe) was barely mentioned in real life before the voyage itself.

For those who have seen the updated 1997 James Cameron version this is, in my opinion at least, much better and manages to get a good story across without the DiCaprio/Winslet love story. It’s a tale of rich and poor thrown together (kind of) in a tragedy much bigger than all of them. The First Class passengers are aloof – indeed at times seemingly oblivious to the fact that most of them are going to die – the Second Class try to behave like their betters and the Third Class (incorrectly called ‘Steerage’ in the movie) party and then panic like the cannon fodder they’ll become in just two short years. I did find it interesting that the lifeboats shown in the film are all pretty full (of women and children mainly) whilst in real life many of them where only 2/3 full or even less. There’s also an interesting scene where More/Lightoller stops a 13 year old boy getting into a lifeboat and then relenting. In real life the boy was shamed into staying on board, despite their being room, and told to ‘behave like a man’ subsequently dying like one. Maybe that kind of reality was too much for 1950’s audiences and would have tarnished both the reputation of the British merchant marine and the international star that was Kenneth More.

Even after seeing this movie many times over the years it still managed to bring a lump to my throat when the captain of the Carpathia – the hero of the hour played by Anthony Bushell (pictured above on the left) – first heard Titanic’s distress call (one of the earliest examples of SOS) and rushed to her aid at top speed despite the ever present danger of ice. Then, of course, was the villain of the piece (no, not the iceberg) the captain of the Californian who apparently ignored all signals from the Titanic despite the fact that she was only 10 or so miles away and could’ve probably saved everyone on board if he’d been paying attention. Apparently Lightoller hated him until his dying day and vilified him at every opportunity.

The slow death of the great ship is handled brilliantly from the shock of impact to the chief designers sad shaking of his head when he calmly reports that she will sink in 90 minutes. Captain Smith, again played superbly by Laurence Naismith, looked suitably shocked and then stoic as he considered the fact that without enough lifeboats and with the Carpathia four hours away at top speed that over 1,000 people are going to die on his watch. Overall this is still a powerfully emotional film – despite the lack of emotion on screen for most of the time. I think that’s one of the things that increases the impact. These people are finding their situation hard to credit (one reason why so many stayed on board – they simply couldn’t believe that it would sink) and yet giving up their loved ones knowing in their heart of hearts that they’re going to die. It’s very affective and effective. If you haven’t seen this classic of the British cinema I recommend that you do especially if you have an interest in the actually event – oh, and look out for original footage of both the Titanic and the Carpathia.      

Cartoon Time.

Name to a Face?

Humans are 'unique super-predator'

By Jonathan Amos

BBC Science Correspondent

20 August 2015


Humans' status as a unique super-predator is laid bare in a new study published in Science magazine. The analysis of global data details the ruthlessness of our hunting practices and the impacts we have on prey. It shows how humans typically take out adult fish populations at 14 times the rate that marine animals do themselves. And on land, we kill top carnivores, such as bears, wolves and lions, at nine times their own self-predation rate. But perhaps the most striking observation, say authors Chris Darimont and colleagues, is the way human beings focus so heavily on taking down adult prey. This is quite different from the rest of the animal kingdom, for which the juveniles of a species tend to be the most exploited. Part of this is explained by the tools that human hunters exclusively can deploy. We can tackle adult prey at minimal cost, and so gain maximum, short-term reward, explained Prof Darimont from the University of Victoria (UVic), Canada. "Advanced killing technology mostly excuses humans from the formerly dangerous act of predation," he told reporters. "Hunters 'capture' mammals with bullets, and fishes with hooks and nets. They assume minimal risk compared with non-human predators, especially terrestrial carnivores, which are often injured while living what amounts to a dangerous lifestyle."

This concentration on large adult prey is triggering extinctions, as well as driving an evolutionary shift towards smaller fish sizes and disrupting global food chains, say the authors. Prof Tom Reimchen, a UVic co-author on the study, uses a financial analogy to explain the damaging consequences of hitting adult populations hardest. He calls the adults the system's "reproductive capital" - the equivalent of the capital held in a bank account or a pension fund. And he says we are eating into this capital when we should really be living off the interest - the juveniles, which many species will produce in colossal numbers, expecting a good fraction to be doomed from the moment they are born via predation, starvation, disease, accidents and more.

The heavily biased preference for adults was not a sustainable strategy long-term, which ought to be clear from fundamental biology, argued Prof Darimont: "In the overwhelming number of cases as fishes age, they become more fecund. That is to say, they produce more eggs, have more babies, and, in fact, in many cases, many of those babies are more likely to survive and reproduce themselves. So when a predator targets that reproductive age class and especially the larger more fecund animals in those populations, we are dialling back the reproductive capacity of populations." In the natural world, predator populations decline when prey are reduced.

However, much of the standard conservation management today is based on the notion that it is the "tiddlers" that should be let go, to ensure robust numbers for the next generation. Trawl nets are often designed specifically to support this approach. Doing it the other way would be challenging, but the technical solutions were available, said Prof Reimchen. "There are traps that can define the entrance to a net, which then very easily allows you to exclude fish above a certain size - in other words, the reproductive capital. Once the motivation is in place, clever people will work out how this transition from the reproductive capital to the interest could be brought about." As for quotas, these should more closely align with the numbers taken out by natural predators, the team suggests.

Dr Chris Carbone studies predator-prey relationships for the Zoological Society of London, UK. He described the research as an interesting study that aimed to put some actual numbers on phenomena that many in the field would recognize. But he cautioned that as broad as the investigation was, the data was still sparse, especially in the marine environment. And as for refocusing the age class to take more juveniles, Dr Carbone argued that it would very much depend on the species in question. Not all species would react in the same way. But he said there was perhaps an even more fundamental problem, which was the density of human predators versus their prey. "We exist at vastly higher densities than natural predators," he told BBC News. "It might be that 100 zebras could support a lion, but in the case of humans we can outnumber our prey in many instances, and that throws the system. So even if we didn't have the efficient hunting technology, we'd still have problems with sustainability."

[Killing is our business and business is good. Humans are indeed very efficient in wiping other species out. It’s because we have no limits, nothing stopping us killing whole groups, decimating whole environments, pushing whole species to extinction. Our more natural competitors kill to eat, while we kill to dominate, for power, status, to prove a point, for revenge, to prevent other predators from eating and, worse, for sport. That is why when humans move into a new environment mass extinctions follow in our wake. We might be described as 'super-predators' but we are much more than that. We are killers – plain and simple.]