The RASNZ Email newsletter is distributed by email on or near the 20th of each month. If you would like to be on the circulation list This email address is being protected from spambots. You need JavaScript enabled to view it. for a copy.

Affiliated Societies are welcome to reproduce any item in this email newsletter or on the RASNZ website in their own newsletters provided an acknowledgement of the source is also included.


1. Sir Patrick Moore Celebrates 88th year and 700th 'Sky at Night'
2. The Solar System in March
3. 2010 AGM and Affiliated Society Minutes
4. Aurora Astronomy School
5. Globe at Night Campaign
6. Nanosail-D Photography Competition
7. RASNZ Conference 2011
8. 2013 RASNZ Conference Needs Host
9. Arthur Page
10. Maurice Collins Invited to Lunar and Planetary Conference
11. Kepler's Latest Planets
12. Saturn's Ring and Icy Moons Explained?
13. BigBOSS Dark Energy Project
14. Cassini Finds Possible Ice Volcanoes on Titan
15. How to Join the RASNZ
16. Here and There

1. Sir Patrick Moore Celebrates 88th year and 700th 'Sky at Night'

Our Honorary Member Sir Patrick Moore celebrates his 88th birthday and his 700th 'Sky at Night' television programme in March. The BBC TV programme has run continuously since April 1957.

To mark the occasion the BBC is putting on a party at Sir Patrick's home 'Farthings' in Selsey, West Sussex, on March 5. His actual birthday is the day before and the 700th 'Sky at Night' is a little after the date.

For a summary of Sir Patrick's varied life see tune-with-music-of-the-spheres-2198463.html published in the Independent on 30 January 2011.

For those with a GPS, Sir Patrick's invitation helpfully includes 'Farthings' coordinates: Lat N: 50° 43' 51" Long W: 00° 47' 49".

2. The Solar System in March

The usual notes on the visibility of the Planets for March 2011 are on the RASNZ web site: Notes for April 2011 will be on line in a few days.

The equinox occurs on March 21 close to 12 noon, NZDT. The sun will of course be moving to the north, with the hours it is above the horizon set to become less than 12.

The planets in march

Only 2 of the 5 naked eye planets are visible during March, Saturn from later evening through to the morning and Venus in the morning.

Mercury is a nominal evening object through March but will never set more than 30 minutes after the sun.

Mars is a morning object but will be too low in the dawn sky to see. By the end of March it will still rise less than an hour before the sun.

Jupiter remains an evening object, but sets just over an hour after the sun on March 1; it will be only 7 degrees up 20 minutes after sunset. The planet will set about 15 minutes later than the sun on the 31st.

Saturn will rise a little before 10 pm (NZDT) early in March, two hours earlier, only some 20 minutes after sunset, by March 31. Thus it will become easily seen in the late evening especially during the second part of the month. The planet will transit and so be highest at about 4 am at the start of the month, and advance to around 2 am by the month´s end.

At midnight on the 1st Saturn will between 20 degrees and 30 degrees above the horizon (lowest in the south and highest in the north). It will be in a direction between east and northeast. Spica, alpha Virginis, will be about 9 degrees from the planet so forming an obvious pair. In the late evening sky the two will be at almost the same height with Spica to the right of Saturn. Spica will be just over half a magnitude fainter than Saturn.

The time Saturn and Spica reach the altitude will advance by 4 minutes each subsequent night, so by 10 pm on the 31st. Two hours later that night, they will be a good 10 degrees higher and have moved round to the northeast.

Once they rise, Saturn and Spica will, of course, remain visible for the rest of the night. In the morning an hour before sunrise, the sky will have rotated to bring Spica almost directly above Saturn. Reddish Arcturus will be nearly 30 degrees to the right of, and slightly lower than, Saturn. An hour before sunrise Spica and Saturn will be to the northwest on the 1st and nearly round to the west on the 31st and then getting distinctly lower in the sky.

The full moon will be some 9 degrees above and slightly left of Saturn on March 20 as seen in the evening. The following morning at about 6am, the moon will be a little closer to Saturn and to its left. When Saturn and Spica reappear in the evening of the 21st, the moon, now just past full, will be less than 2 degrees to the upper right of Spica.

Venus will rise at least 3 hours before the sun throughout the month. Hence it will be an easy morning object visible to the east about 30 degrees up a short while before sunrise.

On March 1 the crescent moon will be some 4 degrees to the upper left of Venus. The following morning the moon, now a thinner crescent, will be 8 degrees below the planet. Venus starts the month in Sagittarius, but by the morning of the 3rd it will have moved into Capricornus. The planet will be crossing the latter constellation for much of the rest of the month, until it moves into Capricornus on the morning of the 26th.

The following morning, the 27th, Venus will be only 25 arc-minutes - less than the diameter of the full moon - above the planet Neptune. Neptune, at magnitude 8, will be visible in binoculars while the sky is still quite dark, say an hour before sunrise. There will be no star visible in binoculars between Venus and Neptune, so the latter should be quite easy to identify. On the morning of the 28th, Venus will have moved to be 48 arc-minutes below and a little to the right of Neptune. Don't confuse Neptune with two brighter stars more immediately to the left of Venus.

On the last morning of the month, the crescent moon will join the two
planets. Venus will now be just over 4 degrees to the lower right of
Neptune, while the Moon will be just over 5 degrees to Neptune' left.

A chart on the RASNZ web site in solar system notes of the month shows the path of Venus past Neptune.

Uranus is at conjunction with the sun on March 21 so will not be observable during the month.

Neptune was at conjunction with the Sun a month earlier than Uranus, so will be moving up into the morning sky during March. The conjunction with Venus will give an opportunity to locate the planet in binoculars.

Brighter asteroids:

(1) Ceres will move up into the morning sky during March. With a magnitude 9.2, it will be about 7 degrees to the right of Neptune. Towards the end of the month, Venus will be a similar distance to the left of Ceres.

(4) Vesta will be a morning object in Sagittarius brightening slightly from magnitude 7.8 to 7.6 during the month. On the morning of the 28th the moon will be about 6 degrees to the upper left of the asteroid, and a similar distance below the asteroid the following night.

(3) Juno and (20) Massalia will be a pair of asteroids only 3 to 4 degrees apart during March. Juno will be to the left of Massalia at 10 pm when the two will be about 20 degrees to the upper left of Saturn. Juno is at opposition on March 12, Massalia 2 nights later. Both will have an opposition magnitude 8.8. They start March at 9.2 and end the month at 9.5

More details and charts for these minor planets can be found on the RASNZ web site. Follow the link to asteroids 2011

-- Brian Loader

3. 2010 AGM and Affiliated Society Minutes

The AGM and Affiliated Society Minutes for 2010 have been placed on the RASNZ website. Go to <> . You will find links to the minutes for 2008, 2009 and 2010. There are also links to the corresponding Annual Reports, that is the reports for the years 2007, 2008 and 2009.

-- Brian Loader

4. Aurora Astronomy School


2011 Aurora School Cancelled

---------------------------- ************************************************************************** Following the February 22 earthquake Canterbury University's 2011 Aurora School has been cancelled. The lack of teaching areas and extension of term 1 into the Easter break make it impossible for academic staff to take part.

-- from an email from Joan Gladwyn, Outreach Coordinator, College of Science, University of Canterbury. ************************************************************************** The Aurora Astronomy School is a unique opportunity for Year 12 and 13 students, and will take place 26th to 30th April 2011, in the Easter vacation. The free camp will be held at the University of Canterbury, and the observatory at Mt. John near Lake Tekapo. On campus we will talk about the universe past, present and future, the life cycles of stars, planet exploration, extraterrestrial life and more. We will then travel to the Mt John Observatory at Tekapo where we will explore our cosmic neighbourhood with modern astronomical instruments. The programme will contain a mix of seminars and practical work.

The closing date for applications for this camp is Friday 25th March. More details are on the application form at

-- Joan Gladwyn, Science Outreach Coordinator, University of Canterbury.

5. Globe at Night Campaign

Join the 6th worldwide GLOBE at Night 2011 campaign. With half of the world´s population now living in cities, many urban dwellers have never experienced the wonderment of pristinely dark skies and maybe never will. Light pollution is obscuring people´s long-standing natural heritage to view stars.

Globe at Night encourages citizen-scientists worldwide to record the brightness of the night sky. During 2 winter/spring weeks of moonless evenings, children and adults match the appearance of a constellation (Orion in February/March and Leo and Crux in March/April) with 7 star charts of progressively fainter stars found at They then submit their choice of star chart on-line with their date, time and location to help create a light pollution map worldwide.

The GLOBE at Night 2011 campaign dates are February 21 - March 6 (worldwide) and March 22 - April 4 (for the Northern Hemisphere) and March 24 - April 6 (for the Southern Hemisphere). 52,000 measurements have been contributed from more than 100 countries over the last 5 years of two-week campaigns, thanks to everyone who participated!


-- from notes sent by Roland Idaczyk and Steve Butler

6. Nanosail-D Photography Competition

NASA is running a competition to encourage photography of NanoSail-D, the first solar sail to circle Earth in low orbit. Amateur and professional astronomers and even casual sky watchers can participate. The solar sail will occasionally be visible to the naked eye when sunlight glints off the spacecraft's 10 m2 sail, producing a spectacular flash akin to an Iridium Flare. Even novice photographers can capture such a bright event. Advanced astrophotographers, meanwhile, will want to try to image the sail through backyard telescopes. It will be a challenge (the sail is only 1 arcsecond across), but even fuzzy pictures could help NASA monitor the condition of the spacecraft. Cash prizes will be awarded to the first ($500), second ($200), and third ($100) place photos, judged by a NASA-appointed panel on the basis of beauty and technical merit.

The contest begins now and ends when NanoSail-D reenters the atmosphere in April or May 2011.

For details see

John Burt, who pointed out this competition, adds that we are better placed at this time of year for satellite observations than those in the northern hemisphere so it could be worth trying.

7. RASNZ Conference 2011

A further reminder that this year's RASNZ Conference is being held in Napier on 27-29 May 2011. The venue is the Napier War Memorial Convention Centre on the north end of Marine Parade. Conference registration forms were sent out with the December issue of Southern Stars, and are also available on the RASNZ Webpage - see There is a wide range of accommodation within easy walking distance of the venue. This ranges from backpackers through to top-notch hotel accommodation. Some suggestions are available by referring to:

Although Conference itself will run from the Friday evening till sometime on the Sunday afternoon, many of you will also want to make time for the other two events. Namely, the Fifth Trans-Tasman Symposium on Occultations which will be held on the Thursday, and into Friday morning, and the Photographic Workshop with David Malin to be held on the Monday following Conference. Graham Blow and John Drummond respectively will provide further information on these in due course.

But back to Conference itself. The Invited Speakers are well known to many of you. Dr David Malin has visited NZ several times in the past, most recently to Stardate South Island in January of this year. David's career has largely been with the Anglo-Australian Observatory (now the Australian Astronomical Observatory). He is also Adjunct Professor of Scientific Photography at RMIT University in Melbourne. David has authored many books on astrophotography, and his images are widely known. As well as presenting a feature paper, David will also be actively involved in the Imaging and Photographic Workshop.

The other Invited Speaker is Dr Fred Watson. Fred is an Englishman by
birth, but has lived in Australia for over 25 years. Fred is Astronomer-
In-Charge of the Australian Astronomical Observatory, and is Project
Leader for the Radial Velocity Experiment. In addition, Fred has been
active in promoting astronomy to the public through, publications, talks
and, more recently overseas tours and theatre shows. In addition to his
feature paper, Fred will be delivering a public lecture later on the
Sunday afternoon following the formal conclusion of Conference.  We look
forward to hearing from these two renowned and respected astronomers. The
titles of their talks will be listed on the RASNZ Webpage in due course.

The Standing Conference Committee is now calling for papers. We invite members and prospective attendees to consider giving a paper and/or poster-paper, and expressions of interests can be made with the Standing Conference Committee - please email: This email address is being protected from spambots. You need JavaScript enabled to view it.. Or better still - please go to the RASNZ Webpage (, and complete and email back the appropriate form for consideration by the Committee. We are please to have received a number of applications to present papers already. There is a final deadline of 1 April when final titles and abstracts need to be submitted, but if you wish to present a paper then please complete the submission form as soon as possible so that we can give it early consideration.

We hope to see many of you at Conference. Good travel discounts are still available for those using public transport. But it would pay to make early bookings.

We also wish to acknowledge Matariki Wines, Holt Planetarium, WASP, Easy
Print, Graham Palmer Photography and Astronomy Adventures as sponsors to
date of the 2011 RASNZ Conference. Also the contributions from the Hawkes
Bay Astronomical Society and the RASNZ Conference Fund are acknowledged.

As with any Conference of the nature of ours, costs are skyrocketing, GST has increased and we have no control over these added costs. So every little bit of sponsorship helps. Having researched the costs of some other conferences attended by primarily amateurs in their fields, I can say without doubt that the RASNZ Conference delivers outstanding value for money.

Further information about Conference is available on the RASNZ Webpage

-- Dennis Goodman, Chair, RASNZ Standing Conference Committee.

8. 2013 RASNZ Conference Needs Host

The RASNZ Standing Conference Committee (SCC) is now calling for applications to host the 2013 RASNZ Conference and AGM.

RASNZ conferences are normally held over a weekend. The Conference generally opens on a Friday evening and continues over the weekend to late Sunday afternoon. The RASNZ rules require the conference and AGM to be held during May unless the RASNZ Council approves an earlier or later date.

Under special circumstances Council may approve that a conference be held outside of May (e.g. second half of April or first half of June) if there are special reasons for doing so. However, because of the requirements of the Charities Commission, the AGM MUST be held prior to the end of June.

Proposals to host the 2013 conference should be in writing (electronic format in Ms Word, or PDF format is acceptable) and addressed to the RASNZ Standing Conference Committee. Proposals should be submitted not later than 15 April 2011 and can either be emailed to This email address is being protected from spambots. You need JavaScript enabled to view it. or posted to:

Pauline Loader
14 Craigieburn Street
Darfield 7520

When submitting an application, please include a likely location (town/city) and venue. Please make sure you clearly state the name of your Society (or group) and who is the contact person for communications. If you have a special reason for wishing to host the RASNZ conference in 2013 (e.g. special events in your area or for your society in 2013) please include a note of this in your submission.

In general, the Local Organising Committee (LOC) looks after the arranging of the venue, catering, registrations, opening and after dinner speakers etc., as well as preparing the budget in conjunction with the RASNZ Standing Conference Committee. The Standing Conference Committee (SCC) is responsible for the programme, speakers etc., and ensuring the overall smooth operation of the Conference. The SCC will provide full support to the LOC and gives guidance in planning and budgeting if needed.

A full set of guidelines and conference requirements can be obtained from the RASNZ SCC by email to: This email address is being protected from spambots. You need JavaScript enabled to view it..

Any queries or questions may be sent by email to: This email address is being protected from spambots. You need JavaScript enabled to view it..

9. Arthur Page

Older RASNZ members will recall Arthur Page of Brisbane. He attended several RASNZ Conferences and IAU Regional Meetings in the 1970s and early 1980s. Arthur died on February 1. The following tribute was circulated to the Astronomical Society of Australia (ASA) by its Secretary, Associate Professor John O´Byrne. --------

I am forwarding the very sad news that Arthur Page, a foundation member of the ASA, died on 1st February.

Arthur will be known to some older ASA members, but is probably only known to most ASA member via the ASA's Berenice Page medal (, named in memory of his wife Berenice. The medal honours excellence in amateur astronomy in Australia and its territories, judged on the basis of scientific contributions which have served to advance astronomy.

Both were foundation members of the ASA when it was formed over 40 years ago. Although most ASA members are professional astronomers, the Pages were readily accepted as members because of the indispensable part they both played in collaborating with Bruce Slee and others from the CSIRO Division of Radiophysics in the IAU Flare Star Programme in the 1960's.

Arthur also had a very interesting earlier history, having served as an Australian army interrogator during World War II because of his command of Japanese. This story is told in a recent book 'Between victor and vanquished : an Australian interrogator in the war against Japan'.

10. Maurice Collins Invited to Lunar and Planetary Conference

Maurice Collins of Palmerston North has impressed everyone with stunning images of the moon taken in recent years. A composite of lunar images all at very low illumination angle was particularly striking. It showed up small variations in terrain height and revealed many ripples in mare lava flows. Now Maurice has been invited to attend the 42nd Lunar and Planetary Conference in Houston. We asked him for some background. ------- Maurice writes:

Some of my recent lunar science work has been published in Selenology Today # 21 (ST-21), the journal of the Geologic Lunar Research group (GLR group), released today . There is a paper about how to process the Lunar Reconnaissance Orbiter Wide Angle Camera images using freely downloadable software called Octave and image processing software ImageJ. ST-21 also has acknowledgment of my independent confirmation of some lunar mountain height measurements.

Also, here is the link to a poster abstract Charles Wood and I are presenting a poster on lunar basins at the 42nd Lunar and Planetary Conference in Houston, Texas that I will be attending for the first time from March 7 - 11, 2011. The abstract is titled "New Light on Old Basins"

The Lunar and Planetary conference has been held every year starting in January 1970, where it was held for the release of the first Moon rock scientific findings. The results were subsequently published in the January 30 1970 issue of Science It has grown since then (and moved several times as it out-grew the facilities) to cover all the solar system topics, but I'm not sure if I will have time for anything other than the Moon sessions as they go all day every day for the week. But it should be fun!

-------- Charles Wood's "The Modern Moon -- A Personal View" (Sky Publishing 2003) is both an observers' guide and a superb account of the moon's geological (selenological?) history. -- Ed.

11. Kepler's Latest Planets

Kepler, America´s planet-hunting space probe, is now really getting into its stride. The craft, which is armed with a telescope that can track more than 100,000 stars simultaneously, looks for slight diminutions of light caused by planetary transits. These transits are mini eclipses-the passage of the planet in question through the line of sight between its parent star and Kepler´s telescope. Transit detection can pick up much smaller planets than previous methods based on gravity-induced wobbles in the stellar parent. The hope is that, soon, it will find one as small as Earth.

On February 2nd America´s space agency, NASA, which controls Kepler, announced the latest results from the probe. So far, it has seen transit- like dips in the light from more than 1,000 stars. In the case of 170 of these the pattern of dips suggests at least two planets; for 45 stars it looks as if there may be at least three planets; in eight cases there may be four planets; in one case, five; and in one other instance, six.

Most of these dips represent only candidate planets at the moment, rather than confirmed ones. Though they have happened often enough to persuade Kepler´s researchers that the dips themselves are real, the way in which the team is conducting its initial search trades quantity of stars for precision of observation. This means that light from a star that Kepler is examining is sometimes "polluted" by light from other stars that appear near to it in the sky. If such a neighbour is a variable star (for example, a double star called an eclipsing binary in which two stars that orbit each other take it in turns to pass in front of one another), that can create the illusion of a transiting planet passing in front of the target star. Each of the candidate systems has therefore to be studied closely, to decide whether there really are planets involved.

In the case of some, that has already been done. As we reported last month [The Economist 15 January, p.77], an object surprisingly similar to an astronomical wild-goose from the 19th century, the mythic planet Vulcan, was found orbiting a star dubbed Kepler 10. And in a paper published by Nature to coincide with NASA´s announcement of its candidates, that discovery was trumped six times over by an analysis of the most populous putative system, Kepler 11, 2,000 light-years from Earth. This shows that the planets in question are, indeed, real.

Jack Lissauer, of NASA´s Ames Research Centre, in California, and his team, have not only confirmed the existence of the six planets, they have worked out their orbital periods, diameters and, in all but one case, their masses. None is quite as small as Earth. They range in diameter from double the Earth´s to 4½ times, and in mass from 2 1/3 times the Earth´s to 13½ times. Nor are any of them orbiting in what astronomers fondly refer to as the "habitable zone" of Kepler 11 - the distance from the star where water on the surface of an Earth-sized planet would be too cool to boil and too hot to freeze. Their orbital periods range from ten to 118 terrestrial days, which would put all but one of them inside the orbit of Mercury, were they going round the sun. The inner two appear, from their densities, to have a lot of water or methane or ammonia in them (or any mixture of the three), along with hydrogen and helium. The other three whose masses are known are less dense, so presumably have more hydrogen. The planet orbiting Kepler 10, by contrast, has an orbital period of a mere 20 hours and is so dense that it is probably made of iron.

None of which sounds all that encouraging for life-hunters. Such optimists, though, need not despair. According to Dr Lissauer, about 50 of the 1,200 or so candidate planets (if planets they be) are orbiting in the habitable zones of their parental stars. These candidates, you may be sure, will be subject to particularly intense scrutiny. The search for a new Earth has now begun in earnest.

-- The Economist, 5 February 2011, p.78.

------ Those who wish to assist with Kepler's searches should register at Thanks to Roland Idaczyk for pointing out this site.

12. Saturn's Ring and Icy Moons Explained?

A new theory for the origin of Saturn's rings explains why they are made almost entirely of ice. It also asserts that the rings are primordial, not the result of a relatively recent encounter. And it accounts for the icy inner moons of Saturn.

Saturn's rings are at present 90 to 95 percent water ice. Because dust and debris from rocky meteoroids have polluted the rings, the rings are believed to have consisted of pure ice when they formed. This composition is unusual compared to the approximately half-ice and half-rock mixture expected for materials in the outer Solar System. Similarly, the low densities of Saturn's inner moons show that they too are, as a group, unusually rich in ice.

The previous leading ring origin theory suggests the rings formed when a small satellite was disrupted by an impacting comet. "This scenario would have likely resulted in rings that were a mixture of rock and ice, rather than the ice-rich rings we see today," says the paper's author, Dr. Robin M. Canup, associate vice president of the Southwest Research Institute Planetary Science Directorate in Boulder, Colorado.

The new theory links the formation of the rings to the formation of Saturn's satellites. While Jupiter has four large satellites, Saturn has only one, Titan. Previous work suggests that multiple Titan-sized satellites originally formed at Saturn, but that those orbiting interior to Titan were lost as their orbits spiralled into the planet.

As the final lost satellite neared Saturn, heating caused by the flexing of its shape by the planet's gravity would cause its ice to melt and its rock to sink to its centre. Canup uses numerical simulations to show that as such a satellite crosses the region of the current B ring, planetary tidal forces strip material from its outer icy layers, while its rocky core remains intact and eventually collides with the planet. This produces an initial ice ring that is much more massive than Saturn's current rings.

Over time, collisions in the ring cause it to spread radially and decrease in mass. Inwardly spreading ring material is lost, while material spreading past the ring's outer edge accumulates into icy moons with estimated masses consistent with the inner moons seen today.

"The new model proposes that the rings are primordial, formed from the same events that left Titan as Saturn's sole large satellite, " says Canup. "The implication is that the rings and the Saturnian moons interior to and including Tethys share a coupled origin, and are the last remnants of a lost companion satellite to Titan."

During its extended mission, the Cassini spacecraft will measure the rings' current mass and will indirectly measure the pollution rate of the rings. This should provide an improved estimate of the rings' age and a test of the new ring origin model.

NASA's Outer Planets Research Program funded this research. The paper, "Origin of Saturn's Rings and Inner Moons by Mass Removal from a Lost Titan-Sized Satellite," by Dr. R.M. Canup, was published in Nature magazine's December 12 Advance Online Publication.

For more see:

13. BigBOSS Dark Energy Project

A proposal to use 500 nights of observing time on the 4-meter Mayall telescope on Kitt Peak, Arizona to investigate the mysterious dark energy has been conditionally approved. Called the BigBOSS Collaboration, the programme would make the biggest-ever map of the universe.

This will require construction of a new spectrograph capable of making simultaneous measurements of thousands of astronomical objects. It will also exploit the three degree field of view that the 4-meter telescope was capable of -- much larger than had previously been recognized. This will enable it to obtain measurements of nearly 5,000 galaxies or stars simultaneously. The project will be further assisted by a new astronomical CCD being developed at Berkeley Lab's microsystems laboratory. It will be supersensitive in the red and infrared wavelengths needed to image very distant objects.

"BOSS" stands for Baryon Oscillation Spectroscopic Survey. The programme will run for five years. In that time BigBOSS will target 50 million objects and find the precise locations in space for almost 20 million galaxies and quasars. It will reach back 10 billion years to the youthful universe. The BigBOSS map will encompass 10 times the volume of the current best map of the universe, now being assembled by the Sloan Digital Sky Survey III¹s BOSS project. Sloan's BOSS project released its first data in January at .

Baryon acoustic oscillation is cosmology-speak for the way galaxies tend to bunch up at roughly 500-million-light-year intervals. These density oscillations had their origin in the pressure waves that moved through the liquid-like plasma of the early, hot universe. When the growing universe "decoupled" -- cooled down enough so that light and matter could go their separate ways -- the density oscillations were recorded in the cosmic microwave background, where they can still be read today.

Since those regions denser in matter became the seeds of today¹s galaxies and groups of galaxies, the cosmic microwave background provides the starting point for a natural ruler to measure how the universe has expanded since decoupling. The greater the number of galaxies and quasars that can be used to measure density fluctuations accurately over time, the more accurate the cosmic ruler will be. This is the primary purpose of BigBOSS and its new spectrograph.

By measuring baryon acoustic oscillation, BigBOSS will study dark energy and can test whether General Relativity is valid. It will also give the astronomical community an unprecedented opportunity to make millions of observations for projects not connected to the primary programme.

Measuring the redshift of each galaxy reveals how much the universe has expanded since its light left that galaxy. A redshift of 0.5, for example, means the universe has expanded 50 percent since the emission of the light. Comparing how distance varies with redshift for many millions of galaxies at different times in the history of the universe will allow precise calibration of the spacing of density oscillations at different epochs.

Dark energy was discovered as a result of comparing the brightness and redshift of individual Type Ia supernovae, which revealed that the universe is expanding at an accelerating rate. Dark energy has "negative pressure" -- that is, by stretching space it counteracts the mutual gravitational attraction of all the matter in the universe, which would otherwise slow down expansion. Although dark energy is thought to constitute some 70 percent of the density of the universe, its nature is unknown.

Theories of dark energy fall into two broad camps. Either dark energy is constant and acceleration is steady, or dark energy varies in time, perhaps even in space. A third possibility is even more radical: dark energy is an illusion, brought on because Einstein¹s General Theory of Relativity, the best explanation of gravitation we have, is wrong or incomplete. With a bigger map of the universe and a more precise measurement of its expansion history, BigBOSS will go a long way toward providing the data needed to choose among these possibilities.

Far beyond dark energy and the measurement of baryon acoustic oscillations, the BigBOSS instrument and the publicly available databases BigBOSS creates will have a major scientific impact on astronomy. The biggest-ever galactic survey will provide new data on cosmological questions including the large- and small-scale structure of the universe, neutrino mass, warm dark matter, and the geometry of space. BigBOSS will provide an unparalleled resource for studying the evolution of galaxies, including our own. It will provide a wealth of new data on quasars. And it will be available for studying such topics as galaxy clusters, planetary nebulae, giant stars, binary stars, and a host of other individual observing programs.

For more see:

-- from a Lawrence Berkeley press release forwarded by Karen Pollard

14. Cassini Finds Possible Ice Volcanoes on Titan

The NASA-ESA Cassini spacecraft has found possible ice volcanoes on Saturn's moon Titan that are similar in shape to those on Earth that spew molten rock.

Scientists have been debating for years whether ice volcanoes, also called cryovolcanoes, exist on ice-rich moons, and if they do, what their characteristics are. The working definition assumes some kind of subterranean geological activity warms the cold environment enough to melt part of the satellite¹s interior and sends slushy ice or other materials through an opening in the surface. Volcanoes on Jupiter¹s moon Io and Earth spew silicate lava.

Some cryovolcanoes bear little resemblance to terrestrial volcanoes, such as the tiger stripes at Saturn's moon Enceladus. There long fissures spray jets of water and icy particles that leave little trace on the surface. At other sites, eruption of denser materials might build up volcanic peaks or finger-like flows. But when such flows were spotted on Titan in the past, theories explained them as non-volcanic processes, such as rivers depositing sediment. At Sotra, however, cryovolcanism is the best explanation for two peaks more than 1000 metres high with deep volcanic craters and finger-like flows.

"When we look at our new 3-D map of Sotra Facula on Titan, we are struck by its resemblance to volcanoes like Mt. Etna in Italy, Laki in Iceland and even some small volcanic cones and flows near my hometown of Flagstaff," said Randolph Kirk. Kirk, a geophysicist at the U.S. Geological Survey, led the Cassini radar 3-D mapping work. Topography and surface composition data also support the idea of an Earth-like volcano landform that erupts in ice.

It is possible the mountains are tectonic in origin, but the interpretation of cryovolcano is a much simpler, more consistent explanation. Cassini's visual and infrared mapping spectrometer revealed the lobed flows had a composition different from the surrounding surface. Scientists have no evidence of current activity at Sotra, but they plan to monitor the area.

Cryovolcanoes help explain the geological forces sculpting some of these exotic places in our solar system. At Titan they explain how methane can be continually replenished in the atmosphere when the Sun is constantly breaking that molecule down.

The results were presented at the December meeting of the American Geophysical Union meeting in San Francisco. More information about the Cassini mission:

-- from a NASA JPL press release forwarded by Karen Pollard

15. How to Join the RASNZ

A membership application form and details can be found on the RASNZ website Please note that the weblink to membership forms is case sensitive. Alternatively please send an email to the membership secretary This email address is being protected from spambots. You need JavaScript enabled to view it. for further information.

The annual subscription rate is $75. For overseas rates please check with the membership secretary, This email address is being protected from spambots. You need JavaScript enabled to view it..

16. Here and There

From The Observatory, 2011 February, Vol. 131, No. 1220.

PERHAPS IN NORWAY? The Sky at Night: Patrick Moore, Dr Chris Davis and Professor John Brown discuss the sun. -- Sunday Times, 2010 April 4, TV programmes for BBC1/2.

Alan Gilmore Phone: 03 680 6000 P.O. Box 57 This email address is being protected from spambots. You need JavaScript enabled to view it. Lake Tekapo 7945 New Zealand

Newsletter editor:

Alan Gilmore   Phone: 03 680 6000
P.O. Box 57   Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Lake Tekapo 7945
New Zealand