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Thursday, June 23, 2011

NASA’s Cassini–Huygens spacecraft has discovered evidence for a large-scale saltwater reservoir beneath the icy crust of Saturn’s moon Enceladus. The data came from the spacecraft’s direct analysis of salt-rich ice grains close to the jets ejected from the moon. The study has been published in this week’s edition of the journal Nature.

Data from Cassini’s cosmic dust analyzer show the grains expelled from fissures, known as tiger stripes, are relatively small and usually low in salt far away from the moon. Closer to the moon’s surface, Cassini found that relatively large grains rich with sodium and potassium dominate the plumes. The salt-rich particles have an “ocean-like” composition and indicate that most, if not all, of the expelled ice and water vapor comes from the evaporation of liquid salt-water. When water freezes, the salt is squeezed out, leaving pure water ice behind.

Cassini’s ultraviolet imaging spectrograph also recently obtained complementary results that support the presence of a subsurface ocean. A team of Cassini researchers led by Candice Hansen of the Planetary Science Institute in Tucson, Arizona, measured gas shooting out of distinct jets originating in the moon’s south polar region at five to eight times the speed of sound, several times faster than previously measured. These observations of distinct jets, from a 2010 flyby, are consistent with results showing a difference in composition of ice grains close to the moon’s surface and those that made it out to the E ring, the outermost ring that gets its material primarily from Enceladean jets. If the plumes emanated from ice, they should have very little salt in them.

“There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus’s icy surface,” said Frank Postberg, a Cassini team scientist at the University of Heidelberg in Germany.

The data suggests a layer of water between the moon’s rocky core and its icy mantle, possibly as deep as about 50 miles (80 kilometers) beneath the surface. As this water washes against the rocks, it dissolves salt compounds and rises through fractures in the overlying ice to form reserves nearer the surface. If the outermost layer cracks open, the decrease in pressure from these reserves to space causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of water vapor is lost every second in the plumes, with smaller amounts being lost as ice grains. The team calculates the water reserves must have large evaporating surfaces, or they would freeze easily and stop the plumes.

“We imagine that between the ice and the ice core there is an ocean of depth and this is somehow connected to the surface reservoir,” added Postberg.

The Cassini mission discovered Enceladus’ water-vapor and ice jets in 2005. In 2009, scientists working with the cosmic dust analyzer examined some sodium salts found in ice grains of Saturn’s E ring but the link to subsurface salt water was not definitive. The new paper analyzes three Enceladus flybys in 2008 and 2009 with the same instrument, focusing on the composition of freshly ejected plume grains. In 2008, Cassini discovered a high “density of volatile gases, water vapor, carbon dioxide and carbon monoxide, as well as organic materials, some 20 times denser than expected” in geysers erupting from the moon. The icy particles hit the detector target at speeds between 15,000 and 39,000 MPH (23,000 and 63,000 KPH), vaporizing instantly. Electrical fields inside the cosmic dust analyzer separated the various constituents of the impact cloud.

“Enceladus has got warmth, water and organic chemicals, some of the essential building blocks needed for life,” said Dennis Matson in 2008, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

“This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets,” said Nicolas Altobelli, the European Space Agency’s project scientist for Cassini.

“If there is water in such an unexpected place, it leaves possibility for the rest of the universe,” said Postberg.

Tuesday, November 21, 2006

Wikinews interviews Lawrence Douglas, Professor of Law, Jurisprudence and Social Thought at Amherst College, on questions of the fairness and credibility of the Saddam Hussein trial, and the purpose, conduct and impact of courts trying international law crimes such as genocide, crimes against humanity and war crimes.

Prof. Douglas is the author of The Memory of Judgment: Making Law and History in the Trials of the Holocaust (Yale University Press, 2001), an acclaimed study of war crimes trials. His writing has appeared in venues including the Los Angeles Times, the Washington Post, and The New Yorker, and he is a frequent contributor to the Times Literary Supplement.

Wednesday, September 4, 2013

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The United States President, Barack Obama, announced on Saturday he was seeking Congressional authorisation for military intervention in Syria.

Wikinews interviewed Professor of Government Dr. Thomas Scotto from the UK’s University of Essex and Senior Lecturer in American and Canadian Studies Dr. Steve Hewitt from the UK’s University of Birmingham about the proposed military intervention by the USA in Syria.

((Wikinews)) What is your job role?

Dr. Thomas Scotto: I am a Professor of Government, teaching courses in quantitative methods, public opinion, political behaviour, and American Politics. I have been at Essex since January, 2007. I am the Principal Investigator of a major ESRC grant on public opinion on foreign policy attitudes in five nations (Great Britain, United States, Canada, France, Germany, Italy).

Dr. Steve Hewitt: Dr. Steve Hewitt, Senior Lecturer in American and Canadian Studies [at the University of Birmingham].

((WN)) The Republican speaker John Boehner is endorsing Barack Obama’s strategy, do you think this will lead to Congress authorising military intervention?

TS: Ultimately, I believe that the President will succeed, but I doubt it will be a neat voter — there will be a significant number of Democrats and Republicans who do not fall into line and vote against intervention.

I think the real story is that in the past two weeks, we have seen an amazing shift in how the Executives of the United States (President Obama) and the United Kingdom (Prime Minister Cameron) execute foreign policy. In the post-War period, committing the nation to take military action was seen as the prerogative of the President and Prime Minister, with the legislatures of both countries providing, at best, weak oversight.

In the United States, there is the War Powers Act and the authorisation of the first Gulf War, but the President’s authority was rarely challenged nor was it really believed that the President needed to consult Congress. In the UK, you would have to go back to the late 1700s to find the last time a Prime Minister was truly rebuffed on a matter of military intervention.

Why is that? I think it’s war fatigue on the part of the public and the average member of the UK Parliament and the US Congress. A significant number of those sitting on the backbenches of Parliament and in the Congress are thinking of balancing their nations’ budgets in times of fiscal austerity, and they have ties to constituencies, which don’t want to see their country shed blood and treasure in another prolonged conflict in the Middle East where the backgrounds of the rebel groups the US and UK are supporting is not well defined and the end goals are uncertain.

SH: Not necessarily. Boehner has not been able to carry Republicans in the past. His being onside increases the chances of authorization but it doesn’t make it inevitable.

((WN)) Is the US general public in support of taking military intervention in Syria?

TS: No, not at all. We’ve polled a representative sample of the American public in June of 2012, February of 2013, and this summer. Support for intervention in Syria has not moved. In our surveys fewer than 1 [in] 5 respondents were open to the idea of sending American ground troops into Syria. This was true regardless whether their aim was to provide humanitarian assistance or topple al-Assad. There are also low levels of support for arming the rebels. What is amazing is that, despite the reported use of chemical weapons and the deaths and displacement of 100,000s of Syrians, there has been little change in support levels over the time period we’ve been in the field with our surveys.

SH: No, clearly the American public is not in favour of intervening in Syria. About 60% are opposed in the latest poll.

((WN)) The British Parliament voted against military intervention in Syria, do you think this has led Obama to put a vote to Congress?

TS: I think Obama wants Congress to own this. Some in Congress believe that the United States would be doing too little if it only carried out limited missile strikes to punish al-Assad. Other Members are dead set against intervention of any type. The President was finding it impossible to please everyone, and instead, basically said sort out what you want me to do. It is an amazing turn of events where the President might be constraining himself in terms of the response he could take. Obama’s decision may have ramifications for Executive-Legislative relations in the US for years to come.

SH:That may have played a role but it is still not clear why President Obama has taken this course. It may also be the case that he is looking to share the political risk that goes with attacking with Republicans and Congress in general.

((WN)) After more than a decade of war in Iraq and Afghanistan, does the US general public feel disillusioned in taking military action?

TS: Yes, definitely. Less than half of the American public believes the Iraq war was a success, and we have found that those who believe that the previous conflicts in the Middle East were a failure are likely to be those opposing action against Syria. So many people think the Iraq and Afghanistan interventions cost too much and did little good — it’s really weighing on the public’s mood at this time.

SH: Yes, there clearly is fatigue in relation to interventions and the lack of clear resolutions of the conflicts in Iraq and Afghanistan.

((WN)) Do you think military intervention in Syria will affect Russia–United States relations?

TS: It is hard to say — in the short term, yes. In the long term, it really depends on how Putin sees the long term interests of himself and his nation vis-à-vis the United States and America’s western allies.

SH: Yes, although relations are already tense. How extensive any attack by the US on Syria will determine the full impact on US–Russia relations.