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

Contents

1. What happened to Comet ISON?
2. Naked-Eye Nova in Centaurus
3. The Solar System in January
4. Stardate North Island, January 3-5
5. Stardate South Island, Feb. 28-Mar.3
6. NACAA and TTSO8, Melbourne, April 18-21
7. RASNZ Conference, Whakatane, June 6-8
8. Kiwi Researchers Secure Leading Role in SKA Project
9. LOFAR Finds Its First Pulsars
10. Tropopause Explained
11. Asteroid Flying Apart?
12. Dark Energy Sought
13. Kingdon-Tomlinson Fund
14. How to Join the RASNZ
15. Signs

1. What happened to Comet ISON?

Comet ISON C/2012 S1 broke up near perihelion. Many astronomers watched the comet disintegrate via the coronagraph telescopes on the Solar Heliospheric spacecraft SOHO.

The comet's nucleus apparently disrupted near perihelion, with the comet's head fading from perhaps a peak brightness of visual magnitude -2 some hours before perihelion to well below magnitude +1 before perihelion.

The brightest feature in the coma of the comet faded steadily after perihelion from about magnitude 3.1 when the comet first appeared from behind the SOHO coronagraph occulting disk on Nov. 28.92 UT to about magnitude 6.5 on Nov. 29.98. By Nov. 30.912 there is no visible nucleus or central condensation. All that remained was a very diffuse dust cloud, largely transparent to background stars, and fading.

-- From IAU Central Bureau Electronic Telegram (CBET) No. 3731, 2013 December 1.

2. Naked-Eye Nova in Centaurus

The second naked-eye nova of the year appeared near Beta Centauri on December 2.

It was first noticed by John Seach, Chatsworth Island, NSW, as a magnitude 5.5 star on images obtained with a digital SLR camera and 50-mm-f.l. f/1.0lens, limiting magnitude 11, taken on Dec. 2.692 UT. John measured its position as R.A. = 13h54m47s, Decl. = -59d09'08" (equinox 2000.0). Nothing was visible at this position on an image taken by him with the same camera on Nov. 26.69 UT (limiting magnitude 11).

Seen by eye at dusk the nova was at an angle of about 7 o'clock from Beta Centauri and at one-third the distance from Beta that Alpha Centauri is. (Alpha and Beta Centauri are known 'The Pointers' to southern sky-watchers who never see the northern pair with the same name. From NZ they are near the southern skyline at dusk this time of year; below the skyline for many of our readers.)

Ernesto Guido, Nick Howes, and Martino Nicolini reported follow-up CCD observations obtained remotely through a 0.50-m f/6.8 astrograph of the iTelescope network at Siding Spring on Dec. 3.68, with coordinate end figures of 45.22s and 04.5". This put the nova just 1".5 from a star listed in USNO-B1.0 catalogue with blue magnitude 15.5 and red magnitude 15.1. An animat ion showing a comparison between Guido et al's image and a red archival Digital Sky Survey (DSS) plate from 1999 is at website URL http://bit.ly/1bfm4IR. If the faint star was the pre-cursor, as is almost certain, then a rise of at least 10 magnitudes is indicated.

Immediate confirmation that the object was a nova, and not a supernova, came from Australian and New Zealand amateur astronomers using low-resolution spectrographs. On Dec. 3.38 UT Malcolm Locke of Christchurch saw Hydrogen-alpha and -beta emission lines indicative of a nova. He was using a 25-cm Newtonian reflector, 100-lines/mm transmission grating and QHY5 camera. Malcolm's spectrum was posted at http://www.flickr.com/photos/malclocke/11187714294/ . On the same night Rob Kaufman, White Cliffs, NSW, got a similar spectrum with a digital SLR camera and a 200-mm-f.l. lens and Star Analyse r grating.

Novae having a large rise in brightness usually fade quickly. Though this one has risen by more than 10 magnitudes it hasn't faded fast. By December 9 it was brighter than magnitude 4.0, rising to 3.7 a couple of days later. It then faded a little but again brightened to 3.5 on the 15th. On the 18 th it was still around magnitude 5.0, easily seen in binoculars in twilight. The nova is now officially designated V1369 Centauri.

-- Mostly extracted from CBET 3732, 2013 December 4, with some cribs from notes to the nzastronomers Yahoo! discussion group and IAUCs 9265 and 9266.

3. The Solar System in January

All dates and times are NZDT (UT + 13 hours) unless otherwise specified.

PHASES OF THE MOON (times as shown by GUIDE)            
New moon:      January  2 at 12.14 am (Jan 1,  11:14 UT)
First quarter: January  8 at  4.39 pm (Jan 8   03:39 UT)
Full moon:     January 16 at  5.52 pm (Jan 16, 04:52 UT)
Last quarter   January 24 at  6.19 pm (Jan 24, 05:19 UT)
New moon:      January 31 at 10.38 am (Jan 30, 21:38 UT)

The Earth is at perihelion on January 5 at 1 am. The Earth will then be 0.9833 AU, 147.1 million km from the Sun.

The planets in january

Mercury is an evening object all month but will be very low and not likely to be visible. It sets only a few minutes after the Sun on the 1st. By the 31st it will set 45 minutes after the Sun. 30 minutes after sunset, at the end of civil twilight, Mercury will be only 3° above the horizon.

Venus starts January as an evening object but sets only some 45 minutes after the Sun, so will be very low following sunset. Within an evening or two it will have disappeared completely. By the 11th it is at inferior conjunction between the Earth and Sun. At conjunction Venus will be 5° north of the Sun as "seen" from the Earth; its distance from the Earth being 39.8 million km (0.266 AU) and 107.8 million km (0.719 AU) from the Sun.

After conjunction Venus becomes a morning object. During the rest of January it moves quite rapidly up into the morning sky, so that by the end of the month it rises nearly 2 hours before the Sun and making it an easy object in the dawn sky.

Mars remains a morning object throughout January, although it will rise just before midnight by the 31st. The planet will be in Virgo. On the 31st it will be about 5° from Spica. During January Mars brightens from magnitude 0.8 to 0.3.

On the morning of January 23 Mars will be just over 6° from the 66% lit moon, with the planet at the apex of a broad, inverted triangle, with the moon and Spica.

Jupiter is at opposition on January 6 so it will rise close to the time of sunset and set close to the time of sunrise. The planet is well north of the celestial equator so will be rather low in southern skies. Even so, particularly by the end of the month it will be a prominent object between no rth and northeast late evening. The planet is in Gemini, only 3° from the magnitude 3 star epsilon Gem by the end of January.

The moon, one day short of full, will be 5° from Jupiter on January 15

Saturn is a morning object, rising by 1am at the end of the month, so it will be well up to the northeast an hour before sunrise. The planet is in Libra forming a broad triangle with the two brightest stars of the constellation. It will be equidistant, 6.5° from each star mid month.

The 35% lit waning moon will occult Saturn on the morning of the 26 January. The reappearance will be visible from New Zealand although the moon and planet will be very low. An occultation of Saturn´s moon Titan also occurs. The time of the reappearance of Saturn is close to 2.02 am for many places in NZ, with Saturn and the moon at an altitude of 5 or 6°. The occultation disappearance of Saturn takes place, at the moon´s lit limb, before moon rise for most of NZ.

Predictions of the precise times of the reappearance at any locality can be obtained using Dave Herald´s Occult program, or contact the writer at This email address is being protected from spambots. You need JavaScript enabled to view it. including your precise longitude and latitude in your email.

Outer planets

Uranus is in Pisces during January. It will set about 1 am on the 1st, and just after 11 pm on the 31st, so by then quite low at the end of twilight.

Neptune is in Aquarius all month. At the beginning of January it will set just before midnight, by the end of January it will set a little over an hour after the Sun, so will become very low in the evening twilight.

Brighter asteroids:

(1) Ceres and (4) Vesta remain as morning objects in Virgo a few degrees from one another and a few degrees from Mars. At the beginning of January Vesta will be 8° from Mars with Ceres another 5° away on the other side of Vesta. All three are moving to the east through the stars, their distances apart decreasing slightly during January. By the 31st the three Solar system objects will nearly be in line with Spica, with the star highest in the dawn sky.

Ceres brightens from magnitude 8.6 to 8.2 during January while Vesta brightens a little more from 7.7 to 7.2. Both will be readily visible in binoculars, their changing position compared to the stars visible from night to night.

(2) Pallas is in Hydra and rivals Vesta as the brightest asteroid in the sky. During January it brightens from magnitude 7.9 to 7.3. At the beginning of January, late evening the asteroid will be about 25° up to the east, about 6° above mu Hya (mag 3.8) and 8° to the right of upsilon1 Hya, mag 4. 1. During the month Pallas will move towards upsilon Hya, their separation being 5° by the 31st.

Pallas rises just before 9.15 pm at the beginning of January and about 7.30 pm by the month´s end. This latter time is a little before sunset. Even so the asteroid will not set until well after sunrise as it is well south of the ecliptic. At the beginning of January the asteroid is above the horizon for 15 hours as seen from Wellington, reducing slightly to 14.5 ho urs by the end of the month.

-- Brian Loader

4. Stardate North Island, January 3-5

Location: Tukituki Youth Camp, Tukituki Valley, near Havelock North, Hawkes Bay. When: Official programme runs from Friday 3rd January - Sunday 5th January. You are also welcome to camp Wednesday 1st January and/or Sunday 5th January for a small extra fee

The camp site in Tukituki Valley offers a wonderful horizon, away from cloud-attracting hills and city lights, as well as the normal campsite facilities. Weather permitting; participants will be looking forward to lots of observing time. Many participants bring telescopes while for others it´s their first telescopic view of the heavens. There is ample opportunity to mix and mingle with other astronomy enthusiasts. Some people here have 30-40 years experience; others are complete newcomers.

Even if the weather is unsuitable for observing, there is a programme of talks, workshops and movies organised to complement skywatching. Whatever the weather Stardate is great astronomical experience. - a chance to ask questions, share ideas, and make or renew old friendships.

If you are interested in attending Stardate 2014 please send an expression of interest to Kay Leather: This email address is being protected from spambots. You need JavaScript enabled to view it..

We want to confirm prgramme details as quickly as possible and we want to put together a varied and interesting programme. If anyone has a presentation that they are prepared to make at Stardate 2014, please let Richard (This email address is being protected from spambots. You need JavaScript enabled to view it.) know as many details as you can.

Extracted from http://www.astronomynz.org.nz/stardate/stardate-2012-review.html

5. Stardate South Island, Feb. 28-Mar.3

Stardate SI will be held at Staveley between Friday February 28th and Monday March 3rd.

Stardate SI is held at a hostel and campsite. It has the following facilities: Full toilet & showers, bunkrooms, auditorium, kitchens with shared fridges and freezers, large cafeteria, plenty of space for tents and caravans. The viewing area has excellent horizons in all directions, and space (no pun intended) for many telescopes.

The surrounding countryside is beautiful, with fine walks through beech forests - we recommend you restrict the walks to daytime 8-).

Stardate SI has the following schedule: Start - Friday February 8th; Registration - from 3:30 pm; Speakers - Fri 8 pm to 9 pm; Viewing - Fri night; Speakers - Saturday 10 am to 11 am; Soapbox - 11 am to noon Group photograph - noon; Update on SI astronomical organistions - 12:30-1 pm; Free time and solar observing workshops - 1 to 5 pm; Trade table - 5 to 6 pm; Telescope walk - 6 pm; Pot luck tea Saturday - 7 to 9 pm; Viewing - Saturday night; Speakers - Sunday 10 am - 12:30 pm; Packup - Sunday or Mond ay at noon (depending on registrations)

REGISTRATION FEES: Approx. $15 per night per person from school age on and free per child under 5 years (actual amounts to be determined). There is no charge for a caravan point. After the refund cut-off date, 24 February 2014, there will be no refunds for cancellations. You can register after this date, however.

Please register on-line at http://www.treesandstars.com/stardate/

NB: Even if you are using a tent you need to register so that we can plan effectively

6. NACAA and TTSO8, Melbourne, April 18-21

The National Australian Convention of Amateur Astronomers (NACAA) is in Melbourne in Easter 2014, 18-21 April.

NACAA aims to bring together amateur (and not-so-amateur) astronomers from Australia, New Zealand, and beyond to share in learning, disseminating and planning cutting-edge astronomical work in the region. We always plan to have a full weekend, Friday to Monday, of various streams of presentations c overing a great width of astronomical work including observing, instrumentation, education, research, history and local activities.

If you would like to be emailed details then go to http://www.nacaa.org.au/2014/interested and sign up for info as it comes available.


The Eighth Trans-Tasman Symposium on Occultations (TTSO8) will be held over Easter 2014, in conjunction with the 26th National Australian Convention of Amateur Astronomers (NACAA) which will be held in Melbourne, Australia, hosted by the Astronomical Society of Victoria. More information on the NACAA meeting is available on its website: http://www.nacaa.org.au/

TTSO8 will feature reviews of recent occultation activity and results, data reduction methods and techniques, updated information on equipment, and sessions devoted to the practical needs of both new and more advanced observers. TTSO8 is expected to draw wide attendance from occultation observers throughout Australia and New Zealand. The organisers also welcome the a ttendance and participation of observers from Asia, Europe and the Americas.

TTSO8's technical sessions will be split across the weekend. The bulk of the presentations will occur on Sunday and Monday April 20-21, with an "Introducing Occultations Workshop" on Friday April 18.

Information on the TTSO8 meeting will be posted to the RASNZ Occultation Section website: http://occultations.org.nz/ Registrations will be done via the NACAA website.

The organisers also invite presentations for the TTSO8 meeting. Presentation proposals should include a title, brief abstract and requested duration. Submissions to TTSO8 should be sent to the organiser, Dave Gault: This email address is being protected from spambots. You need JavaScript enabled to view it.

7. RASNZ Conference, Whakatane, June 6-8

RASNZ members will have received the 2014 conference brochure and registration form with their copy of Southern Stars this month. We encourage you to register early for what promises to be an excellent conference. The hosts, Whakatane Astronomical Society, are marking the society's 50th anniversary in 2014. The conference will be held at the Whakatane War Memorial Hall from Friday 6th June to Sunday 8th June. The venue is situated in Rex Morpeth Park off Short Street. More information can be found on the RASNZ web site.

There is no accommodation at the conference venue, but plenty is available in Whakatane, some within a few minutes walking distance of the venue. Some possibilities are listed on the brochure. Early booking is advisable.

The third Variable Stars South Symposium (VSSS3) will take place on Monday 9th June following the conference. Registration for the VSSS can be made on the conference registration form. The venue for the symposium is the Eastbay REAP centre in O´Rourke Place. This is about 5 minutes walk from t he conference venue.

On the Friday afternoon before the conference opens, the Whakatane local organising committee is arranging a bus tour which will include a visit to the Whakatane Society Observatory. More details are in the brochure.

The guest speaker for 2014 is Dame Jocelyn Bell Burnell, renowned for making the first observations of a Pulsar in 1967. The title of her talk is "Transient astronomy - bursts, bangs and things that go bump in the night".

The 2014 Fellows´ Speaker is Philip Yock, associate professor in the Department of Physics at Auckland University. The title of his talk is "From Particles to Planets".

Further information about the speakers is on the web site

Paper Submissions

The RASNZ SCC is now inviting submissions to present a paper at the 2014 conference. Papers may be presented orally or as posters. All those active in any aspect of astronomy are invited to make a submission to present a paper. Affiliated Societies and RASNZ Sections should take the opportunity to publicise their activities to other members of the RASNZ and the NZ astronomical community by making a presentation at the conference.

Details and a submission form are available on the RASNZ Wiki: http://www.rasnz.org.nz/wiki/doku.php?id=conference:start. Even if you are only thinking about presenting a paper, please let us know by completing a submission form now and giving a likely title.

We look forward to seeing you and hearing you at the conference.

-- Brian Loader, SCC chairman

8. Kiwi Researchers Secure Leading Role in SKA Project

Two New Zealand research groups have secured prominent positions in one of the world´s largest and most ambitious science projects - the Square Kilometre Array (SKA) radio telescope, Science and Innovation Minister Steven Joyce announced today.

AUT University and Victoria University of Wellington will lead two work areas in the pre-construction of the SKA. These two areas are in the Central Signal Processor and the Science Data Processor work packages, working alongside other New Zealand experts.

"The SKA is a global effort to create the biggest and most technologically advanced radio telescope ever built. It will enable astronomers to monitor the sky in unprecedented detail and survey the entire sky thousands of times faster than any system currently in existence," Mr Joyce says.

"While this is a radio astronomy project, one of its exciting features is that the quantity of information that will be gathered by this instrument will be massive; it requires major leaps in information and communication technology to manage, store and interpret the data.

"One of the encouraging features of the SKA project is that a project of this size and complexity can only be achieved through collaboration which will develop and deepen our international linkages.

"The work with international groups is exciting - more than 350 scientists and engineers, from 18 countries, and from more than 100 institutions will be involved. This is an unprecedented opportunity for New Zealand to showcase our expertise in ICT and software development.

"The Government is investing a total of $1.717 million for this project, with New Zealand institutions providing matching contributions, totalling more than $2.17 million over three years.

"During the SKA´s three-year design phase a significant number of New Zealand organisations will be involved including the University of Auckland, Massey University, Victoria University Wellington, Callaghan Innovation, Compucon New Zealand, University of Otago, IBM, Green Button and Open Parallel."

More information on the Square Kilometre Array project is available at: http://www.skatelescope.org/project/

-- A press release from Hon Steven Joyce, Minister of Science & Innovation, passed on by Andrew Lorenc.

9. LOFAR Finds Its First Pulsars

The low-frequency array LOFAR has discovered two new pulsars -- fast- spinning neutron stars, remnants of massive supernova explosions. Two of these weak but quickly flashing radio sources were spotted for the first time during the 'warm-up' for the LOFAR all-sky survey. The results are described in the PhD thesis that astronomer Thijs Coenen of the University of Ams terdam.

The International LOFAR Telescope (ILT) is a radio telescope centred in the Netherlands and spread across Europe. The telescope consists of a network of thousands of individual dipole antennas connected over a fast network to a central supercomputer. The high sensitivity of this software telescope means it is extraordinarily suited for pulsar research. It was designed and built by ASTRON, the Netherlands Institute for Radio Astronomy.

The discovery showcases the pulsar capabilities of LOFAR, and hints at new possibilities with its successor, the Square Kilometre Array (SKA). SKA will take LOFAR technology one step further, and these discoveries show we can expect to detect a large fraction of the pulsars in our galaxy with SKA.

Pulsars act as cosmic lighthouses, emitting radio beams that sweep the galaxy. Their signals allow scientists to study the behaviour of gravity and matter in circumstances so extreme that they cannot be reproduced on Earth, not even in the most advanced facility. Pulsars are important because of this -- they are true cosmic laboratories. So far, about 2,000 pulsars ha ve been identified, but astronomers think there must be about 50,000 active pulsars in our galaxy.

Using computing resources provided by the European Grid Infrastructure, Coenen and the team needed only a month to search through a set of 2010-2013 LOFAR images that would have occupied a single computer for more than a century.

These first results show how LOFAR, with its flexible configuration, can produce more than a 1,000 images per second of a large part of the sky. That means the pulsar survey will be the most sensitive ever in this radio regime.

-- From a press release by the Netherlands Research School for Astronomy (NOVA) and the Netherlands Institute for Radio Astronomy (ASTRON). Forwarded by Karen Pollard.

For background on LOFAR start with http://www.lofar.org/

10. Tropopause Explained

It is known that air grows colder and thinner with altitude, but in 1902 a scientist named Léon Teisserenc de Bort, using instrument-equipped balloons, found a point in Earth's atmosphere at about 40,000 to 50,000 feet where the air stops cooling and begins growing warmer. He called this invisible turnaround a "tropopause", and coined the terms "stratosphere" for the atmosphere above, and "troposphere" for the layer below, where we live -- terms still used today.

Then, in the 1980s, NASA spacecraft discovered that tropopauses are also present in the atmospheres of the planets Jupiter, Saturn, Uranus and Neptune, as well as Saturn's largest moon, Titan. And remarkably, these turnaround points all occur at roughly the same level in the atmosphere of each of t hese different worlds -- at a pressure of about 0.1 bar, or about one-tenth of the air pressure at Earth's surface.

University of Washington astronomer Tyler Robinson and planetary scientist David Catling have used basic physics to show why this happens. Their explanation suggests that tropopauses are probably common to all thick-atmosphere planets and moons.

The reason lies in the physics of infrared radiation. Atmospheric gases gain energy by absorbing infrared light from the sunlit surface of a rocky planet or from the deeper parts of the atmosphere of a planet like Jupiter, which has no surface.

An analytical model showed that at high altitudes atmospheres become transparent to thermal radiation due to the low pressure. Above the level where the pressure is about 0.1 bar, the absorption of visible or ultraviolet light causes the atmospheres of the giant planets -- and Earth and Titan -- to grow warmer as altitude increases.

The physics provides a rule of thumb -- that the pressure is around 0.1 bar at the tropopause turnaround -- which should apply to the vast number of planetary atmospheres with stratospheric gases that absorb ultraviolet or visible light.

Astronomers could use the finding to extrapolate temperature and pressure conditions on the surface of planets and work out whether the worlds are potentially habitable -- the key being whether pressure and temperature conditions allow liquid water on the surface of a rocky planet.

"Then we have somewhere we can start to characterize that world," Robinson said. "We know that temperatures are going to increase below the tropopause, and we have some models for how we think those temperatures increase -- so given that leg up, we can start to extrapolate downward toward the surface."

Robinson's and Catling's paper was published online Dec. 8 in the journal Nature Geoscience [http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2020.html]

-- From a University of Washington press release forwarded by Karen Pollard.

11. Asteroid Flying Apart?

An asteroid showing comet-like features is believed to be close to breaking up due to its fast spin.

The asteroid was discovered in the Pan-STARRS survey on Aug. 27. It was found to have a fuzzy appearance so was given the periodic-comet designation of P/2013 P5. Images taken with the Hubble Space Telescope on Sept. 10 showed the asteroid had six comet-like tails of dust radiating from it like spokes on a wheel. When Hubble looked at the asteroid again Sept. 23, its appearance had totally changed. It looked as if the entire struct ure had swung round.

Mathematical modelling by Jessica Agarwal of the Max Planck Institute for Solar System Research in Lindau, Germany, showed that the tails could have been formed by a series of impulsive dust-ejection events. She calculated that dust-ejection events occurred April 15, July 18, July 24, Aug. 8, Aug. 26 and Sept. 4. Radiation pressure from the Sun stretched the dust into streamers.

P/2013 P5 has been ejecting dust periodically for at least five months. Astronomers believe it is possible the asteroid¹s rotation rate increased to the point where its surface started flying apart. They do not believe the tails are the result of an impact with another asteroid because they have no t seen a large quantity of dust blasted into space all at once.

Radiation pressure could have spun P/2013 P5 up. Lead investigator David Jewitt of the University of California at Los Angeles said the spin rate could have increased enough that the asteroid's weak gravity no longer could hold it together. If that happened, dust could slide toward the asteroid's equator, shatter and fall off, and drift into space to make a tail. So far, only about 100 to 1,000 tons of dust, a small fraction of P/2013 P5's main mass, has been lost. The asteroid's nucleus, which measures 430 metres wide, is thousands of times more massive than the observed amount of ejected dust.

Astronomers will continue observing P/2013 P5 to see whether the dust leaves the asteroid in the equatorial plane. If it does, this would be strong evidence for a rotational breakup. Astronomers will also try to measure the asteroid's true spin rate.

Jewitt's interpretation implies that rotational breakup must be a common phenomenon in the asteroid belt; it may even be the main way small asteroids die.

Jewitt said it appears P/2013 P5 is a fragment of a larger asteroid that broke apart in a collision roughly 200 million years ago. There are many collision fragments in orbits similar to P/2013 P5's. Meteorites from these bodies show evidence of having been heated to as much as 1,500 degrees Fahren heit. This means the asteroid likely is composed of metamorphic rocks and does not hold any ice as a comet does.

-- From a NASA and Hubble Space Telescope Science Institute press release forwarded by Karen Pollard.

12. Dark Energy Sought

Three experiments are starting to study dark energy, the most abundant stuff in the universe. But a theory has just been published purporting to show it does not exist.

In the 1920s astronomers realised that the universe was running away from them. The farther off a galaxy was, the faster it retreated. Logically, this implied everything had once been in one place. That discovery, which led to the Big Bang theory, was the start of modern cosmology.

In 1998, however, a new generation of astronomers discovered that not only is the universe expanding, it is doing so at an ever faster clip. No one knows what is causing this accelerating expansion, but whatever it is has been given a name. It is known as dark energy, and even though its nature is mysterious, its effect is such that its quantity can be calculated. As far as can be determined, it makes up two-thirds of the mass (and therefore, E being equal to mc^2, two-thirds of the energy) in the universe. It is thus, literally, a big deal. If you do not understand dark energy, you cannot truly understand reality. Cosmologists are therefore keen to lighten their darkness about dark energy, and three new experiments-two based in Chile and the third in Hawaii-should help them do so. These experiments will look back almost to the beginning of the universe, and will measure the relationships between galaxies, and clusters of galaxies, in unprecedented detail. When they are done, though the nature of dark energy may remain unresolved, it should at l east be clearer.

If, that is, it actually exists. For a core of cosmological refuseniks still do not believe in it. They do not deny the observations that led others to hypothesise dark energy, but they do deny the conclusion. For them, then, these experiments provide an opportunity to test alternative theories.

The most advanced of the new experiments is the five-tonne, 570-megapixel Dark Energy Camera, which was installed last year at the Cerro Tololo Inter-American Observatory in Chile, 2,200 metres (7,200 feet) above sea level in the Atacama Desert. It will take 400 one-gigabyte pictures of the sky each night, for 525 nights over five years.

This photographic marathon is part of the Dark Energy Survey (DES), a project led by Joshua Frieman of the University of Chicago. Dr Frieman´s plan is to scan an eighth of the sky, examining 100,000 galaxy clusters as he does so and measuring the distances to 300m individual galaxies within those clusters.

The reason for all this effort is that tracing the way the sizes and shapes of galactic clusters change over time allows each round of the battle between gravity and dark energy to be studied in detail. Gravity, which tends to slow down the expansion of the universe, causes clusters to become more compact. Dark energy, which tends to speed universal expansion up, causes clusters to spread out. The rate of contraction or expansion of clusters shows the relative strengths of the two forces. Dr Frieman and his colleagues cannot follow the changes in any given cluster since they see only a snapshot of its history. But looking at the differences between lots of clusters of various ages is the next best thing.

Previous observations have suggested that for more than half of the universe´s 13.7-billion-year life, gravity had the upper hand. Only about 6 billion years ago did dark energy overtake it. The DES hopes in particular to study the transitional period, by peering back as far as 10 billion years by the simple expedient of looking at clusters up to 10 billion light-years away.

The second of the new experiments, the Subaru Measurement of Images and Redshifts (SuMIRe), led by Hitoshi Murayama of the Kavli Institute for the Physics and Mathematics of the Universe, in Tokyo, is based on a mountain top in Hawaii. It will start collecting data next year, in a manner similar to the Dark Energy Camera, but better. Though it will look at only a tenth of the sky, rather than an eighth, it can see farther - 13 billion light-years, rather than 10 billion. It also has more bells and whistles than the Dark Energy Camera; specifically, it has an integral spectrograph, for working out redshifts.

Redshifts are one of astronomy´s most important sources of information. They tell you how far away a galaxy is. The further away the galaxy is, the redder it is. It was this that allowed those 1920s astronomers, led by Edwin Hubble, to work out that the universe is expanding. The Dark Energy Camera , which lacks a spectrograph, has to rely on other telescopes which do have them to make its redshift measurements for it. Having an integral spectrograph will thus give SuMIRe an advantage.

The third experiment, ACTPol (Atacama Cosmology Telescope Polarisation sensitive receiver), run by Lyman Page of Princeton University, is rather different. Instead of looking at light from galaxies, it will study microwaves from the cosmic microwave background (CMB). This was created around 380,000 years after the Big Bang, and thus preserves an imprint of what the early universe looked like.

ACTPol, too, is in Chile, on the peak of a mountain called Cerro Toco. Tests began on July 19th. Its purpose is to look at the CMB´s polarisation, any part of which will have been distorted in meaningful ways by the microwaves´ passage through intervening galaxies from their creation to their arrival on Earth. And from that, using a lot of statistical jiggery-pokery, a third estimate of the yo-yo effect of gravity and dark matter on galactic clusters should emerge. If these three experiments work, and agree with one another, it will be a big step forward in understanding how the universe has evolved from an object smaller than an electron into the vastness seen today. Theoreticians will be able to plug the new data into their models of dark energy, and see what comes out. But others will be able to use the data too. And they may come to different conclusions.

Even as astronomers vie to explain the mystery of the expanding universe, some theorists are trying to explain it away. The most recent such attempt has just been published by Christof Wetterich, of the University of Heidelberg, in Germany. Not only does he not believe in dark energy, he does not believe the universe is expanding at all. That, in the context of modern cosmology, is a pretty grave heresy. But Dr Wetterich´s latest paper, published on arXiv, an online repository, attempts to back it up.

In Dr Wetterich´s picture of the cosmos the redshift others attribute to expansion is, rather, the result of the universe putting on weight. If atoms weighed less in the past, he reasons, the light they emitted then would, in keeping with the laws of quantum mechanics, have been less energetic than the light they emit now. Since less energetic light has a longer wavelength, astronomers looking at it today would perceive it to be redshifted.

At first blush this sounds nuts. The idea that mass is constant is drilled into every budding high-school physicist. Abandoning it would hurt. But in exchange, Dr Wetterich´s proposal deals neatly with a big niggle in the Big Bang theory, namely coping with the point of infinite density at the beginning, called a singularity, which orthodox theories cannot explain.

Dr Wetterich´s model does not-yet-explain the shifts in the shapes of galactic clusters that the Dark Energy Camera, SuMIRe and ACTPol are seeking to clarify. But perhaps, one day, it could. Dr Wetterich is a well-respected physicist and his maths are not obviously wrong. Moreover, his theory does allow for a short period of rapid expansion, known as inflation, whose traces have already been seen in the CMB. Dr Wetterich, however, thinks this inflation did not happen just after the beginning of the universe (the consensus view), for he believes the universe had no beginning. Instead, a small static universe which had always existed turned into a large static one that always will exist-getting heavier and heavier as it does so. There was thus no singularity.

Probably, this theory is wrong. As Cliff Burgess of Perimeter Institute, a Canadian theoretical-physics centre, puts it, "The dark energy business very easily degenerates into something like a crowd of people who are each claiming to be Napoleon while asserting that all the other pretenders are clearly nutty." But theories last only as long as they do not conflict with the data, and when the new experiments have finished there will be a lot more data for them to conflict with, and thus reveal who the real Napoleon actually is. Perhaps, therefore, the last word should go to Niels Bohr, one of the founders of quantum theory. He once said to a colleague, Wolfgang Pauli, "We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough to have a chance of being correct."

-- From "The Economist" 24 August 2013

13. Kingdon-Tomlinson Fund

The RASNZ is responsible for recommending to the trustees of the Kingdon Tomlinson Fund that grants be made for astronomical projects. The grants may be to any person or persons, or organisations, requiring funding for any projects or ventures that promote the progress of astronomy in New Zealand. Full details are set down in the RASNZ By-Laws, Section J.

For an application form contact the RASNZ Executive Secretary, This email address is being protected from spambots. You need JavaScript enabled to view it. R O'Keeffe, 662 Onewhero-Tuakau Bridge Rd, RD 2, TUAKAU 2697

14. How to Join the RASNZ

A membership application form and details can be found on the RASNZ website http://www.rasnz.org.nz/InfoForm/membform.htm. 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, not including the Yearbook. For overseas rates please check with the membership secretary, This email address is being protected from spambots. You need JavaScript enabled to view it..

15. Signs

On a repair shop door: We can repair anything. (Please knock hard on the door - the bell doesn't work.)

Seen during a conference: For anyone who has children and doesn't know it, there is a day care on the 1st floor.

Notice in a farmer's field: The farmer allows walkers to cross the field for free, but the bull charges.

In a London department store: Bargain basement upstairs.

-- Forwarded by Rosemary Cole.

Compliments of the season to all our readers and best wishes for a happy and healthy 2014. - Ed.


Newsletter editor:

Alan Gilmore   Phone: 03 680 6000
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Lake Tekapo 7945
New Zealand