Monthly Archives: August 2010

Some Moon stuff

By which I don’t just mean our Moon, but various moons through the solar system, some of which have been in the spotlight.

Starting out at both Saturn and Earth – and the two are united in having Moons that are slowly shrinking as they cool, the effect being, as on Earth and more dramatically on Mercury, that the outer layer develops wrinkles, seen as mountain chains. Cassini made the discovery for Titan when mapping the icy world’s topography.  Ripples of mountains, all orientated the same and clustered around the equator fitted a computer model of a small body, made of ice and rock with a subsurface ocean, slowly cooling over time as radioactive isotopes decay away. This causes the body to shrink, but the outer parts of the subsurface ocean to freeze and expand. Losing seven kilometres in radius and one percent of volume over the four billion or so years since formation, Titan has achieved two kilometre high mountains in its equatorial ranges. The features seen on our own Moon, by comparison, are much shorter – nine metres or so – but run on for kilometres and cover the whole surface. Equatorial ‘lobate scarps’ were first seen by the Apollo program, but only at the equator. More recent observations with the Lunar Reconnaissance Orbiter have identified further scarps dotted around the Moon. estimates of the shrinking of the Moon from the features suggests around 100m has been lost in around 800 million years, putting the Moon at a lower rate of radius loss than Titan. There is also the suggestion that instabilities in the contraction process are responsible for some of the Moon-quakes observed with Apollo hardware.

Titan wasn’t the only moon under the microscope of Cassini. During one flyby, the probe took images of three moons – Enceladus, Tethys and Dione. Images like this enable scientists to look at changing shadows on the surface of different moons that may help to eke out a little extra detail, or may even reveal a new area of the surface in unprecedented resolution at a given wavelength. They also help others to create computer models of moon surfaces for virtual flyby videos like these.

Of course, they’re also good just for being nice pictures. Stuart Atkinson has put up a post with one of the Enceladus pictures taken by Cassini, and another picture taken from the Mercury bound Messenger probe of a planet and a Moon. The planet happens to be Earth. Messenger wasn’t idly glancing into the void, however, the image was taken during a sweep for Vulcanoids – asteroids lying between the Earth and the Sun, unseen by terrestrial observatories due to the glare of our nearest star. These particular asteroids, should they exist, would be trapped in orbits that never take them as far out as ourselves, rather than actual asteroids or spent comets that have drifted inward. They shouldn’t exist, according to prevailing ideas on the formation of the solar system, so if just one is seen and later confirmed, it would be interesting. It would also mean that alongside the Oort Cloud, the Kuiper-Edgeworth Belt and the Asteroid Belt, we’d also have a Vulcanoid Belt, with new objects to study and slot into the history of the solar system.

For now, we’ll just have to study the solar system through the most ancient rocks available to present day geologists. The most recent block of ancient rock to be found has been dated at around 4.45 billion years old. The Earth is estimated to be 4.54 billion years old and so should the result be confirmed, the arctic rocks would date to a period before the crust of the Earth had formed, but after the core was created. The scientists measured the age looking at well known radioactive decay signatures, though others have suggested a better way would be to look for signatures from istopes believed to be around at the time, but which quickly decayed away in the earliest parts of terrestrial history.

The past and future evolution of planetary systems can have an impact on whether or not there are moons to be found. Hot Jupiter planets – gas giants that have migrated closer to their parent stars – are unlikely to have held onto their moons as they rode the gravitational turbulence further in and dealt with the gravitational forces from the closer proximity to their host star according to new research. Exomoon hunters (like David Kipping, quoted in the article) aren’t detered as the planets do still provide a testbed for observational techniques until our methods and instruments become capable of tackling extra solar planets with a higher likelihood of companion bodies.

Finally, the troubled evolution of Jupiter has been in the news (along with the evolution of its clouds, visible even in relatively small telescopes). The largest of our solar system’s planets has a small problem – its core is a little depleted compared to that of second largest planet Saturn. Current theory suggests that gas giants start out as a giant rocky/ice body, perhaps ten times the mass of the Earth, which then gravitationally hoovers up the gas surrounding it. The trouble is while Saturn shows evidence for the right size of core, Jupiter is a little lacking given its incredible overall mass. A new suggestion has been made that Jupiter’s own core has been in collision with four or five super-Earth’s, each skimming a bit off the top. It is hoped that the forthcoming Juno mission will be able to add observational evidence to the idea.


Some astro publications

With the Royal Society publishing the shortlist for its Science Books 2010 prize, now seems an apt time for some recent space publication news.

Not particularly recent in terms of subject matter, but NASA’s History Division is expanding its library of free eBooks.

ESA have put out the latest edition of its bulletin (online version here). It also has a publication’s website here.

The Geek Calendar, featuring the twitterati of the space world, is available for preorder. All with clothes on, which should help sales no end…

And finally the September issue of Astronomy Now is out and a preview available here.

Some science policy stuff

A survey of political tweets by Tweetminster has shown that Science was among the top thirty-nine tweeted about subjects in politics in the first hundred days of the new government, edging out Mandelson and his memoirs and even the hardy perennial of immigration.

One reason for this is a vociferous campaign on where the axe should fall in the upcoming cuts and reprioritisation of spending. Articles like this in the Sun have been written by scientists. The Government has also been running a project whereby people could send in their ideas on where cuts can be found (of which, the ideas are being collated for people to vote on the best ones at this website). Among those submitting ideas were people affiliated to the Science and Technologies Research Council, who suggested cutting the shared services centre. Another suggestion is to remove the ‘scientific impact’ statement from the grant request assessment procedure (on which it has no bearing, but takes up plenty of time) and perhaps tag it on as a requirement for successful grant requests only, as a follow up to the assessment, which ninety percent of requests fail to make it through. And thirdly, a suggestion I’ve wondered about for a while, is the merger of the seven research councils into one. Not only would this be more cost-effective, it would also make interdisciplinary funding more accessible. Jon Butterworth has more comments on this.

One aspect of science policy is in the news at the moment, with the publication of A-level results, teaching through the universities is in the spotlight. The Telegraph has highlighted an apparent fall in some ratings of UK universities (although others have pointed out at least one of the universities hasn’t actually changed position). But the research groups are getting on with it. UCL has been finding supercomputing time for two projects, for example, one to study turbulence and another to improve solar panels as well as being involved in the first tentative steps into the region of potential new physics through the LHC.

But to make the case for science, it can be useful to demonstrate the impact of science and the space industry on everyday life. The UK Space Agency has been doing just that, looking at the use of satellite derived data in legal evidence, meanwhile the European Space Agency has been highlighting potential new spin offs from the space industry aimed at the oil and gas industry.

Costly new instruments will never have a set of ready made results to prove their worth before building, but they can still make their case. This paper examines the potential science payoff from the European Extremely Large Telescope (Unique Selling Point – it is big) and the FAQ page for the Large Synoptic Survey Telescope (USP, it looks at things that change in brightness or position and sends out alerts to scientists) includes everything down to the crossover between what it can see and what an amateur telescope can spot. But things like this, really big projects, tend to require either their own sources of funding or for the community to come together and decide they fit with the priorities of the field over the coming years. This is assessed by various means including the Decadal Survey and decisions taken by ESA and the STFC. Thoughts on the results of the latest decadal survey and what it means for the shape of astronomy over the next ten years can be found on Sarah Askew and In the Dark among many, many others.

Moving onto science journalism and the baying twitter mob whose growth was fostered by various attacks on science, impending cuts and the election, has been on the lookout for potential breaks in the quality of science reporting. This led to one poor reporter’s innocent request for information supporting a story to be savaged before the mob realised this was a friend not foe and apologised. The kind of things the mob are on alert for, asides from general bad science, include things like these Sins of Science Journalism. In the absence of warning labels on journalistic content,  and in the face of perennial hoaxes such as this, the word of mouth, or tweet of fingers, is all we have.

Some citizen science stuff

Been out of action for a week or so, now time to try and round up bits and pieces of all the news I missed…

First up is Solar Storm Watch, which allows data from solar observation probes to be analysed by users of the website. They have announced that through their twitter feed, people will soon be alerted in close to real time when a storm has erupted in our direction, giving some idea of when the best time to look for aurorae, like these, might be. That video involved Stuart Clark, who wrote a book called the Sun Kings, which includes the story of the first observation of a solar flare linked to a resulting auroral storm, one by Richard Carrington in 1859, and who recently recommended ten good easy going books for astronomy enthusiasts.

Secondly, the original Zooniverse project Galaxy Zoo has turned its best known story – the discovery by user Hanny van Arkel of an unusual feature in the zoo data that turned out to be an unusual and very large form of nebula, the origins of which are still contested – into a comic. They have produced promotional cards and will be premiering the comic on the web at 3am on the 4th of September (because Dutch discoveries in a UK based program do need to be premiered in the USA…).

Some spaceflight stuff

The weekend has seen quite a bit of activity. The final activity for Robonaut 2 before being packed away for transport to the International Space Station can be seen in this video:

Meanwhile some humans who also hope to be stationed up there or thereabouts someday have also been undergoing some activity – underwater activity familiarising themselves with performing Extra Vehicular Activities, or spacewalks. The ESA Astronaut Candidates performed their EVA training in the Neutral Buoyancy Laboratory at the European Astronaut Centre, in Cologne, Germany. Pictures here.

Other future space missions were in the spotlight as well. Russia and India are collaborating on a triple mission to the Moon, set for a 2013 launch. The mission will see an Indian rocket launch an Indian orbitting spacecraft, a Russian Lunar lander and an Indian lunar rover. The landing parts haven’t yet had a site chosen, but opinion favours the South pole, which is at a higher latitude than any previous mission, would allow more continuous communications and may improve chances of digging down and touching Lunar ice. Meanwhile, another Lunar mission by China has also been targetted at 2013, setting up an Eastern space race to be the first hardware on the surface of the Moon since 1976.

Of course, it might be nice if China did a bit of cleaning up closer to home as the nation has been revealed as the source of forty percent of the 10,000 or so bits of space debris in orbit of the Earth. The USA is second on 27.5 percent and Russia, whose space agency commissioned the report, third on 25.5 percent. The reason why China has so many bits floating about up there compared to the two powers who went up earlier and sent far more rockets in their time was the decision by the Chinese military to show off an anti satellite device that turned one defunct satellite into 2,800 pieces, which alone is more than the number of things left by second placed America.

NASA, meanwhile, is contemplating a mission to somewhere not very well covered – the surface of Venus. With suggestions that Venus may once have had continents, may well have been volcanically active more recently than previously assumed and with the low level of data we have on what it really looks like beneath the thick, swirling clouds, a mission called SAGE has been proposed. Landers on the surface of Venus last only a short while before succumbing to the intense pressure and temperatures, so SAGE intends to pack in as much as possible in the few hours it would have after landing on the flank of a possibly active volcano, Mielikki Mons. It would try to drill, to sample the air, to take spectral measurements of the composition of the ground, the subsurface, the gases and to send back as many images as possible before the second largest terrestrial planet swiftly destroys the newcomer as it has done all previous missions beneath the clouds – the present record for transmission from the surface was the 127 minutes of data from Venera 13 in 1982. If successful, SAGE’s 2016 launch would see it on the way to becoming the first landing on Venus since 1985.

NASA aren’t the only USA launchers in town. An Air Force Satellite was launched by the United Launch Alliance on an Atlas V rocket. Picture here.

And finally, Cassini has been revisiting the Tiger Stripes on Enceladus, the tiny, icy satellite of Saturn. The tiger stripes are now known to be areas from which vast amounts of water are shooting from inside the satellite and Cassini has taken images in the infrared to detect heat structures within the stripes and understand the mechanisms behind the ejection of the water. Previous flybys were inappropriate for the infrared instruments to be used as the surface flew by too quickly on previous low orbits.

Report on the Kendal Solar System Scale Model

A quick admission to make, due to the weather rather spoiling my plans, I never did a walkabout of the solar system scale model held in Kendal on Waterside. I did see bits of it getting set up, all the way up to Uranus – where I was stationed. I had decided I would go walkabout at around three o’clock, but part of my duties involved showing people the Sun through a Coronado Personal Solar Telescope, kindly donated for the day by Robin Leadbeater, and as luck would have it from about half two until half four (thirty minutes after the official end of the event) I was deluged with people either wanting to watch the Sun, or standing at the ready for when the next break in the clouds came.

Instead, my time was spent by the bridge over the Kent, next to the Abbot Hall playground alongside volunteer Neil Wheeler and a sign indicating Uranus. As Neil took charge of delivering quick bursts of information on the planet formerly known as Neptune George III Great Britain (snappy, why did they ever rename it?) amongst other things, I stood forlornly by a telescope pointed at the clouds.

Then there was a small break – just enough for me to point the telescope towards a bright light not often seen. Then another crack in the clouds, just enough to tune the telescope to show the bright regions, granulation, prominences and a filament. Another crack and the focusing was adjusted.

One o’clock seemed to spark off the first real wave of people coming through, following the sporadics in the first hour. After this point, more and more people flowed steadily through, many stopping to try and catch the Sun in one of the rare breaks in the cloud. Eventually, larger areas of blue sky started to filter through and rather than taking a quick walk to Pluto, people elected to wait until one arrived, providing a good dozen or so people queuing at a time. Old hands, mothers with babes in sling (at least two of those), young children (for which the telescope was lowered) and everyone in between. Even a member of the Cumbrian Skies group of the Stargazer’s Lounge found time to drop by.

Several people had their fears about looking directly through a telescope at the Sun calmed with a quick chat about how the Coronado rejected 99.9% of the light coming into it and selected only a tiny fraction to see. As a result, they got their first views of the solar surface magnified by around 40x and for those who were able to focus on the detail (for some, it took some time, for others it was instant), the views were memorable. One young boy called the Sun ‘creepy’ when he saw the feathered edges and sinuous detail like the filament (called variously, ‘the tadpole’ and ‘the wiggly thing’) and the brighter glowing regions. The Sun is coming out of the deepest solar minimum for a century, making the views even more special. The reasons behind that apparently lie in a conveyor belt of plasma that has been spinning round faster than normal in recent years, but not stretching as far down in previous cycles as it does now. But the activity (measurable through new techniques such as using the polarisation of light to detect the magnetic field structure), and the resulting auroral signals, provided some talking points for visitors.

But dragging myself away from the solar viewing (by the shorn tips of my fingers), going both on the account of the happy faces arriving at Uranus and the official event write-up by organiser Stuart Atkinson, the day went well with people by the dozen flowing through and seeing just how big things in our tiny corner of the galaxy are and getting in most cases their first filtered look at the thing that holds the entire solar system together. The Sun.

Brian Cox as he isn’t usually seen

With his present high public profile, Professor Brian Cox (who tweets here) is probably more familiar in areas like this, explaining how Titan’s lakes were detected by Cassini in the Wonders of the Solar System program. However, as his title implies, he does actually work in academia, on projects relating to the Large Hadron Collider. His latest scientific paper is available for all to see (dealing with how the way in which the theoretical Higg’s boson – which provides mass if it exists – can have the strength of coupling to other particles measured by how they decay into other particles when exposed during a high energy collision in a particle accelerator), though it is perhaps not quite as accessible as the TV programs.

Of course, a little reediting of the Wonders of the Solar System has led to other ways to see another face of Brian Cox – like this.