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. Two Devastating Earthquakes
2. The Solar System in April
3. Notice of Annual General Meeting
4. 2011 Aurora School Cancelled
5. Globe at Night Campaign
6. Global Astronomy Month April 2011
7. RASNZ Conference 2011
8. Host Sought for 2013 RASNZ Conference and AGM
9. Pictures from the Lunar and Planetary Conference
10. Ken Ring's Weather and Earthquake Forecasts
11. MESSENGER Orbits Mercury
12. Solar Mystery Solved
13. How to Join the RASNZ
14. Paraprosdokian (funny) Sentences

1. Two Devastating Earthquakes

Two devastating Earthquakes occurred in the past month. A magnitude 6.3 quake close to Christchurch killed around 180 people in the CBD. A much bigger shake, magnitude 9 and 300 km off the coast of Japan produced a devastating tsunami that destroyed towns and villages along several hundred km of coast, killing thousands. Our thoughts are with friends and colleagues in both places.

Canterbury Earthquake On February 22 a Richter magnitude 6.3 earthquake devastated much of central Christchurch and some surrounding suburbs. Being centred just 10 km southeast of the CBD and only 5 km down the quake produced much more severe shaking than did September 4's magnitude 7.1 earthquake. The earlier quake was centred near Darfield, some 40 km west of Christchurch at a depth of 15 km. [See Newsletter No. 118, Item 2.]

A Wikipedia article forwarded by Philip Barker gave an early analysis: "... the vertical acceleration was far greater than the horizontal acceleration. The intensity felt in Christchurch was MM VIII. [MM is the Modified Mercalli scale. It gives the shaking intensity on the ground. The Richter magnitude gives the total energy release of the earthquake. -- Ed.] The peak ground acceleration (PGA) in the Christchurch area exceeded 1.8g (i.e. 1.8 times the acceleration of gravity), with the highest recording 2.2g, at Heathcote Valley Primary School, a shaking intensity equivalent to MM X+. This is the highest PGA ever recorded in New Zealand; the highest reading during the September 2010 event was 1.26g, recorded near Darfield."

Later analysis indicates that the quake energy was 'aimed' at the Christchurch CBD by the direction of the fault. Bill Fry, a seismologist with Geological and Nuclear Sciences, was reported in the 'The Press' (March 18, p.A4) as saying that the waves from the fault rupture, and the rupture, were moving in the same direction, concentrating the energy.

The historic Townsend Observatory, at the old University of Canterbury site -- now the Arts Centre -- in downtown Christchurch, was destroyed. The observatory tower had been weakened by the September earthquake. Plans were afoot to remove the venerable Townsend Telescope from the observatory once the tower had been stabilized. The telescope was a 6-inch Thomas Cooke & Sons refractor made in 1864. Sadly the February 22nd quake overtook this work. Photos of the observatory and the telescope appear on the cover of the March issue of Southern Stars. On page 9 of the same issue is a photo taken by Mita Brierley of the destroyed tower with, presumably, the telescope in the debris. Mita, a recent Canterbury PhD in astronomy, was part of a search and rescue team working in the CBD after the earthquake.

Canterbury University's Department of Physics and Astronomy is housed in the Rutherford building on the University's Ilam campus west of the CBD. The building is a solid 1960s Ministry of Works design. Early indications are that it has no structural damage, despite several more recent buildings on the campus being 'red stickered'. It is hoped that students and staff can re-occupy Rutherford in mid April.

Japanese Earthquake As far as is known, the shaking from the March 11 Japanese earthquake did little damage to astronomical equipment. Sendai Observatory (E Long. +140° 51.9', Lat. +38° 15.4', altitude 45 metres) is the closest well- known astronomical facility to the epicentre.

The global effects of the earthquake are still being calculated. Some early results have been seen in the news media. The Japanese east coast moved 4 metres east. The oceanic plate (on the other side of the plate boundary) moved 20 metres west. The dipped part of the plate, a slab 400 km wide and 100 km long, moved down about 10 metres.

Earth's axis moved 16.5 cm. This is no big deal. The Earth moves many metres in relation to the axis every year. It's called the Chandler wobble. Earth's rotation rate shortened by 1.8 microseconds. So a day is now 1.8 millionths of a second shorter that it was before. The length of day varies by tens of milliseconds (thousandths of a second) over a year due to northern hemisphere seasons. In both cases it is caused by stuff being moved closer to, or further from, the rotation axis.

-- Alan Gilmore --------- William Tobin notes that there is an article by John Hearnshaw about the Townsend Observatory and telescope at John Field found photos of the destroyed Townsend Observatory posted on Facebook. The pictures, source not given, can be seen at

2. The Solar System in April

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

A reminder that NZDT ends on the first Sunday of April, that is April 3 at 3 am.

The planets in april

Only two of the five major planets will be readily visible during April. Saturn will be in the sky most of the night. Venus, in the morning, will rise well before the Sun making it readily visible in the dawn sky.

Mars will also be a morning object as will Jupiter and Mercury after their conjunctions with the sun early in April. By the end of the month all three planets are likely to be visible low to the east shortly before sunrise. The grouping of the 3 and Venus in the morning sky is going to lead to a series of planetary conjunctions starting in April but mostly in May.

Saturn is the only evening planet for April. It is at opposition on April 4, so will become visible in the evening from the time the sky darkens, rather low early evening at first but gaining altitude later in the month.

The distance between Spica, alpha Virginis, and Saturn will increase from 11 to 13 degrees during April. In the evening the two will be at about the same level, with Spica to the right of Saturn. The star will be just over half a magnitude fainter than the planet.

On the evening of April 17, the almost full moon will be above the pair and close to equi-distant from them about 9.30 pm. The moon will then be at the apex of a slightly obtuse angled isosceles triangle with Saturn and Spica forming the base. Later in the evening and in the early morning, the moon will get a little closer to Spica.

The north pole of Saturn will be tilted at about 8 degrees towards the Earth during April, the tilt actually decreasing slightly during the month. As a result the rings will be visible in a small telescope as a narrow band either side of the planet.

The morning sky

Venus will be the only planet readily visible in the morning sky throughout April. It will rise at least two and a half hours before the Sun. Even so it will be getting lower in the dawn sky during the month. Viewed through a small telescope, Venus will be seen to be like a small, brilliant gibbous moon. It will be 80% lit at the beginning of April and 87% lit at the end of the month.

The planet starts April in Aquarius, by the 18th its easterly motion will see it in Pisces. A few mornings later Venus will pass close to Uranus. The two planets will be about a degree apart on the mornings of the 23rd and 24th of April. On the 23rd Uranus will be to the lower left of Venus, the following morning Uranus will still be on the left but a little higher than Venus. At magnitude 5.9, Uranus will be an easy binocular target while the sky is still reasonably dark. There will be no stars nearby bright enough to be confused with the planet.

On the morning of the 1st the crescent moon will be 8° below and a little to the left of the Venus. The crescent moon will be back near Venus again on the last morning of the month, some 11° to the upper left of the planet. The two will be a little closer the following morning, May 1.

Mercury, MARS and JUPITER all start April too close to the Sun for observation. On April 1 Mars does rise about an hour before the sun, but is unlikely to be seen in the morning twilight.

Jupiter is in conjunction with the Sun on April 7, after which it becomes a morning object. Mercury is at inferior conjunction three days later marking its return to the morning sky. Neither is likely to be visible until late in April.

During April, Mars moves a little further from the Sun, so that by the end of the month it will rise 90 minutes before our star. The planet´s actual time of rise changes little all month. Mars will remain as a low object in the dawn sky, on April 30 only 7.5° up 45 minutes before sunrise.

Mercury and Jupiter will move away from the Sun into the morning sky more rapidly than Mars. Mercury will catch up with Mars on the morning of April 20 when the two planets will be 37´ apart. Mercury, magnitude 2.4, will be to the left of Mars, magnitude 1.2. They will be very low, barely 6 degrees above the horizon 45 minutes before sunrise. In azimuth, they will be about 12.5 degrees to north of east. The pair will be 15 degrees below Venus and slightly to its right.

Jupiter catches up with Mars at the end of the month. On the last morning of April Mars will be 49' to the upper right of Jupiter. 45 minutes before sunrise they will be some 7.5 degrees above the horizon in a direction 17 to 18 degrees north of east. At magnitude 2.1, Jupiter should be a reasonably easy object to locate. Venus will be 11 degrees above the pair and slightly to their left. Jupiter and Mars will, in fact, be closer the following morning, only 25' apart.

Uranus, in Pisces, also gets higher in the morning sky during April. Mars passes it on the morning of the 4th, when the two will be less than 15´ apart. They will be less than 3 degrees above the horizon 45 minutes before sunrise, making observations difficult. As noticed above, Venus passes Uranus on the morning of the 23rd and 24th.

Neptune, in Aquarius, gets well up into the morning sky during April. On the 1st it is 5.5 degrees above Venus, by the end of the month the distance between the two will have increased to 32 degrees.

Brighter asteroids:

(1) Ceres is a morning object in Aquarius with a magnitude 9.3 to 9.4. On the 1st it will be 7 degrees to the upper right of Venus. By the 30th Vesta will be 27.5 degrees above the planet

(4) Vesta is also a morning moving from Sagittarius to Capricornus on the morning of April 3. Its magnitude will brighten slightly from 7.6 to 7.4 during the month.

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. Notice of Annual General Meeting

The 2011 Annual General Meeting of the Royal Astronomical Society of New Zealand will be held at 4.30pm on Saturday 28 May 2011 at the Napier War Memorial Conference Centre on Marine Parade, Napier. Notices of motion are invited and should reach the Executive Secretary by 1 April 2011.

-- Rory O´Keeffe, Executive Secretary, 662 Onewhero-Tuakau Bridge Rd RD 2, TUAKAU 2697. This email address is being protected from spambots. You need JavaScript enabled to view it.

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. 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 School was advertised in the February 21 Newsletter, Item 4.

5. Globe at Night Campaign

Join the Globe at Night global project.

Awareness of the impacts from wasteful artificial lighting on our out-door environment is growing. Wasted energy, health and ecological impacts and loss of our view of the universe are all part of those impacts. The Globe at Night Project gives a measure of one impact of this wasted resource, the loss of our night sky.

Please take some time between the 24th of March and the 6th April to count some stars. It's easy to do and there are some clear instructions at

Look for the southern hemisphere Family Activity Packets at the bottom of the web page: English, South (Crux), English, South (Leo).

-- Steve Butler, RASNZ Dark Skies Group

6. Global Astronomy Month April 2011

Astronomy Without Borders presents: Global Astronomy Month April 2011. Global Astronomy Month continues the excitement of the unprecedented International Year of Astronomy 2009 (IYA2009).

(AWB) Astronomers Without Borders is dedicated to fostering understanding and goodwill across national and cultural boundaries by creating relationships through the universal appeal of astronomy.

Astronomers Without Borders projects promote sharing. Sharing resources. Sharing knowledge. Sharing inspiration. All through a common interest in something basic and universal.

Sharing the sky. A host of events are planned worldwide throughout April 2011 (see list below), all amateur and professional astronomers and in fact anybody is invited to participate, encourage your local astronomy club to run at least one event for the public, giving the public a chance to explore and enjoy our night sky.

If your Astronomy club in New Zealand has events planned please let me know very soon, a Press Release will go out to the New Zealand media organisations on the 25th March, we can advertise your events in this release. March 24 to 6 April Globe at Night - Southern Hemisphere 1 April Online Messier Marathon: Observe all the Messier objects remotely 1 to 8 April International Dark Skies Week 1 to 30 April 30 Nights of StarPeace 2 April Around the Ringed Planet: Observe Saturn remotely 2 to 3 April Beatuy without Borders - Saturn Watch 9 April Global Star Party

Be sure to reserve Saturday, April 9th, for GAM´s ultimate observing event: the Global Star Party. Of course, it´s B.Y.O.T. - Bring Your Own Telescope - but encourage even those who don´t have one to come anyway. All are invited, all will be excited. It is amazing that when we turn our gaze upward all religious, national, cultural and political barriers fade into the darkness. April 9th is the time to come out under the stars, bridge gaps across the seas, and join your brother and sister skywatchers in proving that the world is, in fact, "One People, One Sky."

9 April Stars for All: Observe deepsky objects remotely

  1. to 16 April Lunar Week
  2. April Walking on the Moon: Observe Moon remotely
  3. April Yuri's Night - 50th Anniversary of Human Space Flight
  4. April SunDay 17 April Here Comes the Sun: Observe Sun remotely
  5. to 22 April Meteors without Borders - Lyrids Watch 2011
  6. April, 20:00UT Cosmic Concert - Online Musical Concert
  7. April Write Your Name in the Sky!: Observe asteroids remotely Throughout April One Star at a Time - Fight Light Pollution Throughout April MoonDays Throughout April Astronomy without Barriers - programs for people with disabilities Throughout April Planetarian without Borders Throughout April Astropoetry for Global Astronomy Month

You are also invited to register your event at

You are also invited to join the AWB New Zealand Google group newsletter to keep up to date with the AWB events in New Zealand.

Here are some ideas to get the public in your area involved in GAM April 2011 Visit a retirement home, or children´s hospital and give those able a chance to see the Universe up close. Have a club member dress up as a famous astronomer from history. Use our resources page to get the materials to accommodate the seeing impaired. Host "How Telescopes Work" demonstrations and put your ATM guys to work with mirror grinding demos and use some of that extra glass to let the public try. Hold events outside of art galleries or musical events. Surround a shopping mall or city park with telescopes at every corner or entrance. Get a local scout or school group to assist at your star party-have the youngsters ask questions, provide information, and even help run the scope. Have an "artists table" set up so that younger observers can make and take their own souvenirs of the event. Work with a local library to have book displays set up near the telescope so that people can learn more. Work with another club in a different country and set up an internet connection so that those attending your event can connect with others doing the same thing at the same time in a different part of the world.

Live-stream your event on Ustream.

All the best with your GAM 2011 events, remember to let us know what you have planned so we can advise New Zealand media organisations in our 25th March 2011 press release.

-- Robert McTague, Astronomy With Out Borders New Zealand Coordinator, 28 Kiwi Drive, Timaru. Ph 03-688 3735. -------------- For web links to the various activities see

The Lyrid radiant is very low from New Zealand; unlikely to be of any public interest here. -- Ed.

7. RASNZ Conference 2011

A further reminder that this year's RASNZ Conference is being held in Napier on 27-29 May 2011. This is little more than 2 months away now. Registrations are coming in, and if you have yet to register we recommend you get onto this fast - late next month the late registration penalty fee will come in. 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 mid 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. Hopefully via the RASNZ Newsletter, also via the RASNZ Webpage.

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 has already called 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 good 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. Of concern is a lack of papers from the southern parts of NZ. SCC recognises the people of Christchurch and Canterbury in particular have had other major matters to contend with (SCC being coincidentally Canterbury-based personnel-wise at present), but hopefully some of the Canterbury people will be able to come to conference and make presentations.

We hope to see many of you at Conference. Good travel discounts may be harder to come by, by now. But there are still good accommodation deals. The LOC in Napier has already indicated some suggestions - see link above - and I have just checked on the Wotif site (, and there are good deals available still. Just don't delay - the earlier bookings are done the less they will cost.

Information regarding the Annual General Meeting, and the Affiliated Societies Meeting will be advised separately from this item.

The Local Organising Committee has also some other activities organised - art deco tour, observatory visit, and other activities will be advised to registrants in due course.

We also wish to acknowledge Matariki Wines, Holt Planetaruim, 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. Host Sought for 2013 RASNZ Conference and AGM

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. Pictures from the Lunar and Planetary Conference

Last month we noted that Maurice Collins had been invited to attend the 42nd Lunar and Planetary Conference in Houston. Maurice has now followed up with photos from the Conference. The notes below are from his posts to the nzastronomers group.

Here are the official photos from the first poster session to give a feel of it (mine was at the second on Thursday). I enjoyed the poster sessions the best as more informal. [The photos give a feel for the enormous area that poster panels cover at international conferences. -Ed]

The Kaguya Lunar Atlas shown is Chuck Wood's latest book, which is for sale on Amazon now, and I can highly recommend! (plug-plug). It is non- technical and has some great lunar orbital images of the Moon.

I have uploaded some (there are lots more) of my photos from Johnson Space Center to my website if you want to see what I got to see there:

10. Ken Ring's Weather and Earthquake Forecasts

New Zealand self-publicist Ken Ring has been getting attention from the more gullible news channels with his predictions of earthquakes. These are based on pseudo-science involving the moon. He uses the same theory to predict weather -- with much the same success.

Beliefs in such theories, and the believers, are more a topic for religious studies and psychology than for astronomy. However, readers who field enquiries about Ring and his theories will find useful background at

Analysis of Ring's weather forecasting is found at

An earlier prize-winning series of articles by Bill Keir is held in the Auckland Astronomical Society's archive at /Oct2004/PseudoWeather.asp

-- Thanks to Mike McGavin, Rob Beck and others for passing on these links.

11. MESSENGER Orbits Mercury

NASA's MESSENGER spacecraft went into orbit around Mercury on March 17. This is the first time a spacecraft has accomplished this engineering and scientific feat. MESSENGER's main thruster fired for approximately 15 minutes slowing the craft by 3000 kph hour and easing it into the planned orbit about Mercury. The rendezvous took place about 154 million km from Earth.

Getting into orbit around Mercury is the biggest milestone for MESSENGER since its launch more than six and a half years ago. The craft has travelled 7.8 billion km, making encounters with Mercury to reduce its speed and orbit size.

Engineering tests will be made for the next several weeks. These will most particularly ensure that the spacecraft's systems are all working well at the high temperatures one-third of Earth distance from the sun. On April 4 the mission's primary science phase will begin.

"Despite its proximity to Earth, the planet Mercury has for decades been comparatively unexplored," said Sean Solomon, MESSENGER principal investigator of the Carnegie Institution of Washington. "For the first time in history, a scientific observatory is in orbit about our solar system's innermost planet. Mercury's secrets, and the implications they hold for the formation and evolution of Earth-like planets, are about to be revealed."

The craft's name is contrived from MErcury Surface, Space ENvironment, GEochemistry, and Ranging. Few readers will need reminding that in Greek and Roman mythology Mercury, aka Hermes, was the messenger of the gods.

-- From a Johns Hopkins University Applied Physics Laboratory press release forwarded by Karen pollard.

12. Solar Mystery Solved

The Sun has been in the news a lot lately because it's beginning to send out more flares and solar storms. Its recent turmoil is particularly newsworthy because the Sun was very quiet for an unusually long time. Astronomers had a tough time explaining the extended solar minimum. New computer simulations imply that the Sun's long quiet spell resulted from changing flows of hot plasma within it.

"The Sun contains huge rivers of plasma similar to Earth's ocean currents," says Andres Munoz-Jaramillo, a visiting research fellow at the Harvard-Smithsonian Center for Astrophysics (CfA). "Those plasma rivers affect solar activity in ways we¹re just beginning to understand."

The Sun is made of a fourth state of matter -- plasma, in which negative electrons and positive ions flow freely. Flowing plasma creates magnetic fields, which lie at the core of solar activity like flares, eruptions, and sunspots.

Astronomers have known for decades that the Sun's activity rises and falls in a cycle that lasts 11 years on average. At its most active, called solar maximum, dark sunspots dot the Sun's surface and frequent eruptions send billions of tons of hot plasma into space. If the plasma hits Earth, it can disrupt communications and electrical grids and short out satellites.

During solar minimum, the Sun calms down and both sunspots and eruptions are rare. The effects on Earth, while less dramatic, are still significant. For example, Earth's outer atmosphere shrinks closer to the surface, meaning there is less drag on orbiting space junk. Also, the solar wind that blows through the solar system (and its associated magnetic field) weakens, allowing more cosmic rays to reach us from interstellar space.

The most recent solar minimum had an unusually long number of spotless days: 780 days during 2008-2010. In a typical solar minimum, the Sun goes spot-free for about 300 days, making the last minimum the longest since 1913.

"The last solar minimum had two key characteristics: a long period of no sunspots and a weak polar magnetic field," explains Munoz-Jaramillo. (A polar magnetic field is the magnetic field at the Sun¹s north and south poles.) "We have to explain both factors if we want to understand the solar minimum."

To study the problem, Munoz-Jaramillo used computer simulations to model the Sun¹s behavior over 210 activity cycles spanning some 2,000 years. He specifically looked at the role of the plasma rivers that circulate from the Sun¹s equator to higher latitudes. These currents flow much like Earth¹s ocean currents: rising at the equator, streaming toward the poles, then sinking and flowing back to the equator. At a typical speed of 40 miles per hour, it takes about 11 years to make one loop.

Munoz-Jaramillo and his colleagues discovered that the Sun's plasma rivers speed up and slow down like a malfunctioning conveyor belt. They find that a faster flow during the first half of the solar cycle, followed by a slower flow in the second half of the cycle, can lead to an extended solar minimum. The cause of the speed-up and slowdown likely involves a complicated feedback between the plasma flow and solar magnetic fields.

"It¹s like a production line -- a slowdown puts 'distance' between the end of the last solar cycle and the start of the new one," says Munoz-Jaramillo.

The ultimate goal of studies like this is to predict upcoming solar maxima and minima -- both their strength and timing. The team focused on simulating solar minima, and say that they can't forecast the next solar minimum (which is expected to occur in 2019) just yet.

"We can't predict how the flow of these plasma rivers will change," explains lead author Dibyendu Nandi (Indian Institute of Science Education and Research, Kolkata). "Instead, once we see how the flow is changing, we can predict the consequences."

Their findings appeared in the March 3 issue of the journal Nature. The paper is co-authored by Nandi, Munoz-Jaramillo, and Petrus Martens (Montana State University and Center for Astrophysics).

-- A Harvard-Smithsonian Center for Astrophysics (CfA) press release forwarded by Karen Pollard.

------ For more on this see

13. 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..

14. Paraprosdokian (funny) Sentences

A paraprosdokian is a figure of speech in which the latter part of a sentence or phrase is surprising or unexpected in a way that causes the reader or listener to reframe or reinterpret the first part. It is frequently used for humorous or dramatic effect.

If I agreed with you, we'd both be wrong. We never really grow up; we only learn how to act in public. Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad. The early bird might get the worm, but the second mouse gets the cheese. Why does someone believe you when you say there are four billion stars, but check when you say the paint is wet? A clear conscience is usually the sign of a bad memory. The voices in my head may not be real, but they have some good ideas! A diplomat is someone who can tell you to go to hell in such a way that you will look forward to the trip.

You're never too old to learn something stupid.

-- Thanks to Graeme Murray, among others, for passing this along.

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