march society journal · a 2013 study by astronomers using the hubble space telescope estimated...

March 2015

SOCIETY JOURNAL Society Meeting Monday 9th March at 8:00pm Comets and Origins by Clement Plantureux

Comets and Origins

The talk will review the history of comet observations through to the development of the scientific understanding of their nature, including an overview of the latest discoveries of the Rosetta/Philae mission.

Clément studied Geosciences and remote sensing in France before completing a Bachelors degree in Astronomy at the University of Colorado, Boulder (USA). He is currently serving as an Intern at the Auckland Stardome while visiting New Zealand.

Comet Lovejoy showing the complex ion tail

with two contrasting views of comet

Churyumov—Gerasimenko Source‐APOD

SOCIETY JOURNAL, March 2015 2

Calendar of Events for 2015

April 2015 Programme March 2015 Programme

Mon 2 8:00pm Introduction to Astronomy with Bernie Brenner and Peter Felhofer

Fri 6 7:00pm

&

8:00pm

Young astronomers with Margaret Arthur & David Wardle.

Mon 9 Society Meeting Comets and Origins

Mon 16 7:00pm

8:00pm

Astrophotography Group With Keith Smith Practical astronomy with Bill Thomas

Wed 18 7:30pm Council Meeting

Mon 23 8:00pm Film Night with Gavin Logan.

Fri 3 7:00pm

&

8:00pm

Young astronomers with Margaret Arthur & David Wardle.

Mon 6 8:00pm

Introduction to Astronomy with Bernie Brenner and Peter Felhofer

Mon 13 8:00pm Society Meeting

Mon 20 7:00pm

8:00pm

Astrophotography Group With Keith Smith Practical astronomy with Bill Thomas

Wed 22 7:30pm Council Meeting

Mon 27 8:00pm Society AGM

Sat 18 3:00pm Warkworth Radio Astronomy Telescope Tour.

Courtesy of AUT.

Sat 15 5:00pm Dark Sky Observing Night

BBQ and telescopes at Wainui. See website for Details. More by email

Welcome to new members

Marc Touchette (Family)

Mijail Linares (Ordinary))

Nancy Holland (Ordinary))

Ben Hart (Ordinary))

Heiryck Gonzalez (Family)

Joe Allen (Family)

Leon Smyth (Ordinary))

Hanneke Bouchier (Ordinary))

Tony Daniell (Ordinary))

Genevieve Bing (Youth)

Nicci Davies (Family)

Peter Horne (Family)

Peter Cartwright (Ordinary))

Nilesh Gounder (Country)

Pawan Withana (Youth)

Liam Murphy (Youth)

Bruce Matchett (Ordinary))

Dave Gardner (Country)

Igor Khripunov (Family

Practical Astronomy Monday March 16

Note the change of date due to the Moon’s phase.

The Autumn Night Sky This month we have one of our seasonal planetarium sessions, where we will review the Autumn night sky. Weather permitting we will follow up the planetarium session with an outdoor sky tour and observing using the EWB Zeiss telescope and courtyard scopes. If the weather is not suitable we will screen a planetarium show.

Film Night Monday March 23 at 8:00pm

10 Things you didn’t know about volcanoes

With Gavin Logan This film looks examines some of historys most famous volcanic eruptions and what caused them. It also looks at the nature of the Earths Crust and Plate Tectonics.

3 WWW.ASTRONOMY.ORG.NZ


Where is everybody? Are we a cosmic fluke?

By Nayalini Brito The Fermi Paradox

I n 1950, Nobel laureate Enrico Fermi asked a glib but powerful question: “Where is everybody?” He was

referring to the absence of extra-terrestrial visitors to Earth and, after voicing the question, is said to have proceeded (after a series of mental calculations - which he was very well known for - based on the probability of Earth-like planets, the probability of life given an Earth, the probability of humans given life, the likely rise and duration of technology etc.) to state that the Earth ought to have been visited a long time ago and many times over. He concluded that interstellar flights were impossible or, if they were possible, that they may not be worth the effort or, technological civilisations did not last long enough for this to happen (Jones 1985).

A 2013 study by astronomers using the Hubble Space Telescope estimated that there are 225 billion (i.e. 2 x 10^11) galaxies in the observable universe (Sky & Telescope Web) and there are about 10^11 stars in our galaxy (Newman and Sagan 1981), making the number of stars in the observable universe about 10^22 or even as high as 10^24 (ESA Web). Statistically-based rather than scientifically-based intellectual argument for the existence of extra-terrestrial intelligence (ETI) is illustrated by Newman and Sagan’s (1981) view that there may be 10^5 to 10^6 worlds linked by a common colonial heritage. This assumes an abundance of planets around the multitude of stars, the general cosmic circumstances as sufficient requirements for life, the seemingly selective advantage of intelligence and technology and the availability of billions of years for evolution. But there has been no evidence of ETIs in any shape or form despite 50+ years of proactive Searching for Extra Terrestrial Intelligence (SETI). This apparent contradiction expressed by Fermi with his now-famous question “where is everybody” was named the Fermi Paradox by Carl Sagan (Shklovski and Sagan 1968).

The Fermi Paradox has led to much discussion and debate over 60+ years with a multitude of possible explanations offered with no generally accepted resolution. This paper seeks to resolve the Fermi Paradox by examining its various key facets.

From 1961, efforts to detect ETI within our galaxy were initiated with much enthusiasm by a group of leading scientists based on an estimate of the reasonable probability of the existence of ETI (expressed as the Drake Equation and discussed in Section 2). These have yielded null results to-date leading to debate within the scientific community as to whether Earth and Earth-life are rare and hence either ETI does not exist or is unlikely to be detected (the Rare Earth Hypothesis discussed in Section 3) or whether extra-terrestrial communities (ETCs) do exist with whom we may make contact some day in the future (led by SETI and discussed in Section 4). Rather than reinvent the wheel, this paper also evaluates the various Fermi Paradox resolutions that have been proposed over the years and filters issues worthy of further consideration (Section 5) prior to proceeding to discuss the selected other key current issues in greater detail (Sections 6) and weighs up the findings (Section 7).

In science, proof is rare and in the areas associated with the Fermi Paradox even the availability of data is poor as the fields concerned are young and evolving. Having reviewed the various arguments and the available research and data, this paper concludes that the absence of evidence is not evidence of absence and that on balance, it is likely that ETI exists despite the fact that we have not yet detected or made contact with them and concludes that difficulties with interstellar communications and interstellar travel as the resolution to the Fermi Paradox (Section 8).

Drake Equation and its implications

In 1961, Frank Drake, put together a simple equation (later to become famous as the Drake Equation) to serve as the agenda for an invitation-only meeting held at Green Bank convened by Frank Drake at the request of J. P. T. Pearman of the U. S. National Academy of Sciences from 1-3 November. The participants consisted of scientific luminaries viz. Nobel laureates Harold Urey (chemist), Joshua Lederberg (biologist) and Melvin Calvin (chemist) along with a slightly less-well celebrated group consisting of physicist Philip Morrison, radio communications expert Dana Atchley, Hewlett-Packard’s Bernard Oliver, astronomer Otto Struve and his researcher Su-Shu Huang, neuroscientist John Lilly and Lederberg’s protégé, the then young post doc (later to become an iconic astrophysicist) Carl Sagan (Billings 2013).

The Drake Equation (given below) is neither mathematical nor scientific but just a tool, a product of seven factors, to predict the number of civilisations like ours that we might detect with our instruments (Drake 2013).

N = R x f^p x nê x f^l x fî x f ^c ^ L where

N = Number of detectable advanced civilisations in our Galaxy

R = Average rate of star formation in the Milky Way

f^p = Fraction of Stars that form planets

nê = Fraction of Planets suitable for life per star

f^l = Probability that life evolves in habitable planets

fî = Probability of evolution of life to intelligence inhabitants

f^c = Probability of intelligent life with technologies and choose to communicate

L = Lifetime of a technologically advanced civilisation

It served as a framework to discuss the relevant variables that fell into the disciplines of astrophysics, planetary science, evolutionary biology, psychology, sociology etc. and with this framework, the multi-disciplinary group of attendees of the Green Bank Conference collectively estimated each of the variables and concluded that (i) there were about 10,000 detectable advanced civilisations in our galaxy (see Table 1 below) and, (ii) as all the other variables more or less cancelled


each other out, the value of L (the lifetime of a technologically advanced civilisation) was the key factor that dominated the results of the equation (Billings 2013).

Table 1: Original Estimation of the Drake Equation in 1961

At the time, only R (the rate of star formation in the Milky Way) had been reasonably constrained with the remaining six factors estimated, in Drake’s own words, based on very indirect evidence which could be called either “subjective probabilities” or “informed guesses” (Drake 2013). The estimates of each of the factors ranged from reliable to highly speculative as they moved down in order. This estimation of N (the number of detectable advanced civilisations in our Galaxy) was a theoretical intellectual exercise with in-built assumptions that (i) environments similar to the Earth are likely to exist elsewhere in the galaxy; (ii) as life exists on Earth, it is likely to exist elsewhere; (iii) life is likely to evolve into intelligent life; (iv) such life is likely to develop technology and culture; and (v) such life would wish to establish contact with other intelligent life in the galaxy. These assumptions were capped off with a final most speculative assumption for L (the Lifetime of a technologically advanced civilisation) which is both the most challenging to quantify and the one that controls the ultimate value of N (the number of detectable advanced civilisations in our Galaxy).

The range of estimates for N has varied from 10^-5 to 10^6 by “contact pessimists” and “contact optimists” respectively (Fogan 2009).

Despite these various drawbacks, 50+ years later, the Drake Equation is still in active use within the scientific community. Progress in the fields of exoplanets and habitable zones (discussed in Section 6 below) has enabled more reliable

estimates for the values for f^p (Fraction of Stars that form planets) and f^l, (Fraction of Planets suitable for life per star). Some examples of the Drake Equation using more recent estimates are given in Table 2 below.

It is interesting to note from Table 2 above that while Drake remains as optimistic as ever (N=10,000), other recent estimates are extremely modest (N=6 and N=10). However, once recent findings on exoplanets and habitable zones are factored in, the estimate of N by Rothery et al. (2011) increases from 10 to 400 showing the impact of the improvement in the quality of available data on the ultimate outcome demonstrating the sensitivity of the Drake Equation to reliable quality of data on the variables that it is made up of. The Drake Equation is also a statement of our ignorance – our knowledge of many of the variables is poor to non-existent. Although those variables based on astrophysics and planetary science (R, f^p, n^e) have been reasonably constrained over the past 50+ years, the estimates of the biologically (f^l, f^i) and sociologically (f^c, L) based variables remain speculative and influence the widely ranging estimates of detectable advanced civilisations in our galaxy.

Despite theoretical estimates, the observational efforts to-date to detect ETI (discussed in Section 4 below) have yielded null result. With the Earth as the only example, at present the only reliable value for N is 1. Table 2: Recent Estimation of the Drake Equation in 2011


The thinking behind the Drake Equation is based on the Principle of Mediocrity (also known as the Copernican Principle), which takes the view that the Earth is not at the centre of the Solar System and the Universe. Rather the Earth is a small planet orbiting a commonplace star in an unremarkable part of the Milky Way and therefore we cannot be the only planet where unique intelligent life has evolved, but instead the Earth is one of many such planets in the galaxy. In addition to the drawbacks of being probability-based and not research-based or observational evidence-based and the lack of reliable data for the biological and sociological variables, this view is challenged by the Rare Earth Hypothesis discussed in Section 3 below.

3. The Rare Earth Hypothesis

Top scientists Peter Ward and Donald Brownlee have put together powerful, carefully researched and scientifically supported arguments for the Rare Earth Hypothesis in Ward and Brownlee (2000) which discount many parts of the Universe as “dead zones” (viz. early universe, globular clusters, elliptical galaxies, small galaxies and edges of galaxies due to being metal-poor; centres of galaxies due to their energetic processes; planetary systems with “hot Jupiters” as they drive the inner planets into the central star; planetary systems with giant planets in eccentric orbits as unstable; and future planets as likely to lack plate tectonics due to the scarcity of uranium, potassium and thorium) and lists 18 Rare Earth factors (viz. right distance from star, right mass of star, stable planetary orbits, right planetary mass, Jupiter-like neighbour, a Mars, plate tectonics, ocean, large moon, the right tilt, giant impacts, the right amount of carbon, atmospheric properties, biological evolution, evolution of oxygen, right kind of galaxy, right position in galaxy, wild cards such as snowball Earth and Cambrian explosion) which are shown as low probability occurrences.

The Rare Earth Hypothesis takes the view that microbial life originates readily and forms frequently in countless planets or moons that have warm, wet environments somewhere in their interiors, but views intelligent life as rare. Despite the fact that no life has been detected in the solar system as yet, this view is supported by recent scientific discoveries such as extremophiles and the promising apparently habitable environments in Titan, Europa, Enceladus etc. The contention of the Rare Earth Hypothesis is that origin of life as a single-celled organism evolving through to multicellular organism to animals to intelligent life forms with culture such as humans although assumed (by the Drake Equation and SETI enthusiasts) is unlikely. This is because various evolutionary paths (triggered by various cosmic and also a number of mass extinction events) took place for Earth-life to co-evolve with the Earth. Such a chain of events is very complex and have “rare” chances of occurring. They argue that life formed 4 billion years ago early in the life of the Earth, but the evolution to complex life took far longer - the development of an Oxygen atmosphere and a very large number of evolutionary adaptations both took billions of years - and the Earth needs to not only be in the habitable zone to begin with, but remain in the habitable zone (continuous habitable zone) during that time which is a rare occurrence given “dead zones” and the 18 Rare Earth factors listed above.

On the face of it, the arguments in support of the Rare Earth Hypothesis, although the factors listed are not all independent

of each other, are compelling and appealing as they are strongly supported by research and observational findings to-date which are fully detailed with a strong list of supporting references in Ward and Brownlee (2000). However, it too has various in-built assumptions that need consideration. The arguments are based on the Anthropic Principle (i.e. the cosmological principle that theories of The Universe are constrained by the necessity to allow human existence (OED Web 1)) and are concerned with biospheres and factors of life similar to what we find on the Earth - they seem to see Earth-life as the only example rather than as a single known example of how life works.

Five years on from proposing the Rare Earth Hypothesis, Peter Ward has explored the topic “life-as-we-do-not-know-it” (Ward 2005) and takes the view that while carbon-water based Earth-life may be hard to find given the Rare Earth factors, other locations could be suitable for alien life based on silicon-methane for example. There are 1.6 million named and identified species on Earth (Ward 2005) and the evolutionary process on Earth has given rise to humans. Convey Morris (2005) provides highly detailed and sound scientific research referenced analysis on the process of convergence, its ubiquity and how it applies to all life including alien life which could look very much like Earth-life despite possessing profoundly different internal chemistry. This supports the view that potential alien life could evolve into intelligent ETCs.

While Ward and Brownlee (2000) demonstrate with good scientific support that microbial life originates readily and forms frequently in countless planets or moons (their main argument is the rarity of Earth-like biospheres), there are other viewpoints such as that of respected evolutionary palaeobiologist, Convey Morris (2005). Morris argues strongly and convincingly that that although finding a suitable planet and getting the right recipe for the origination of life may be difficult (he agrees that finding suitable biospheres like Earth can be rare), once life originates, the emergence of human intelligence and sentience is a near-inevitability (his main argument) which goes counter to the Rare Earth Hypothesis. This view is also supported by Bogonovich (2011) who states that the diffusion hypothesis (or the random walk) suggests that an intelligent species will eventually evolve.

Fogan (2009) uses a method of Monte Carlo realisation and allowing for the errors and ignorance in SETI parameters, evaluates other competing theories of life and intelligence and concludes as set out in Table 3 below.

The theories covered are:

Panspermia – life may spread form one original planet to many others carrying life to form concurrently in multiple systems

Rare Life Hypothesis – once life arises it can evolve into intelligent life but initial appearance of life is itself hard

Tortoise and Hare Hypothesis – life evolves easily on many planets and is susceptible to self-destruction; the evolution towards intelligence and advanced civilisation is more complex but is more likely to survive


Table 3: Forecasts for advanced ETIs for different theories of life and intelligence

Hypothesis Panspermia Rare Life Tortoise and Hare

N_planets 4.8 x 10^8 4.8 x 10^8 4.8 X 10^8

N_inhabited 691,000 80,000 684,000

N_fledgling 76,000 730 75,000

N_destroyed 38,000 370 43,000

N_advanced 38,000 360 32,000

Source: Fogan (2009)

These forecasts show that the likelihood of ETIs is not vanishingly small. Further, a similar numerical testing of the Rare Earth Hypothesis using Monte Carlo realisation techniques shows that the Rare Earth Hypothesis is not completely contact pessimistic, but one that is contact optimistic for a small subset of Communicating ETIs (CETI) and while most intelligent civilisation pairs (ICPs) are unconnected as they are unable to exchange signals at lightspeed in the limited time they are both extant, the few that are connected will be strongly connected (Fogan and Rice 2010).

For pragmatists, the Rare Earth Hypothesis is a stance that is well supported by current scientific research and evidence. However, it is not without its drawbacks (e.g. evolutionary convergence, possibilities of alien life) and in applying "Occam’s Razor" approach (i.e. the scientific principle that in explaining a thing no more assumptions should be made than are necessary (OED Web2)) it goes against the development of scientific history of pursuing ideas that are not always based on conventional thoughts - a process that has been going on since Copernicus. Science involves thought experiments, i.e. a hypothesis that is put forward for the purposes of thinking through the consequences, and the Drake Equation is also a thought experiment which provided the support and momentum for SETI, reviewed in Section 4 below.

SETI (Search for Extra-Terrestrial Intelligence)

SETI was born in 1959. While the seminal SETI paper, seen as the blueprint for the modern SETI, was being published by Cocconi and Morrison (1959), Frank Drake was independently preparing to perform the very experiment proposed in that paper (Shuch 2011).

In 1960, for just a few weeks, Project Ozama scanned a narrow band of frequencies surrounding the Hydrogen emission line and observed two nearby Sun-like stars (Tau Ceti and Epsilon Eridani). This was followed by the Green Bank conference which generated the Drake Equation and a strong interest in SETI by a wider group of leading scientists of the day.

In 1971, Project Cyclops was designed by NASA involving large scale hardware and software for a sophisticated SETI receiving system. Consisting of 900 large parabolic reflector antennas and advanced optical computer for multi-channel spectral analysis, this carried an estimated cost of tens of billions of US dollars and hence was never built, however, it remains valid as a blueprint for such a system (Shuch 2011).

In 1992, NASA SETI launched two complementary strategies – (i) to search nearby Sun-like stars and (ii) to undertake a methodical sweep of the entire sky for signals emanating from

stars not specifically known to us. Despite the fact that the cost of this program was an affordable US$ 12.6 million per annum (Shuch 2011), after a year of observation it was cancelled by the US Congress in 1993 for economic reasons.

The privately funded SETI Institute revived the target search component of the NASA SETI program as Project Phoenix in 1995 and monitored 1,000 nearby Sun-like stars across a substantial portion of the microwave spectrum over 10 years. This involved renting time of large radio telescopes such as Parkes and Mopra Australia, Green Bank in West Virginia, Arecibo in Puerto Rico and Jodrell Bank in the UK. This observation was done out to 240 light years from Earth and at a frequency range of 1.2 to 3 GHz (Forgan and Nichol 2011).

From 1996, a not-for-profit organisation, SETI League, resurrected the all sky survey component of the NASA SETI programme as Project Argus by co-ordinating thousands of small amateur radio astronomer who built and operated radio telescopes online with operations in 144 stations in 27 counties on seven continents (Shuch 2011). The all sky narrow band microwave search for ETI signals is in the “water hole” (as it corresponds to a gap in the radio noise coming from space located between the hydrogen line and the strongest hydroxyl (water) line) between 1400 and 1720 MHz (Forgan and Nichol 2011) as it has been argued that any ETI trying to communicate over interstellar distances would know about the H^1 line at 1.4 GHz and the OH lines around 1.7 GHz (Lazio 2009).

The privately funded Allen Telescope Array of SETI has 42 of the 300 dishes planned targeting about 250,000 stars including stars with known exoplanets in the “water hole” while also doing deep blind survey (20 square degrees) towards the Galactic centre looking for signals from the billions of stars there (Forgan and Nichol 2010).

Although SETI appears to have been operating for 50+ years and therefore, on the face of it, it appears that much effort has been made by SETI to detect ETIs producing only null results, in reality the efforts to-date can only be best classified as extremely modest because the SETI effort has been strongly limited by available technology. It has also been affected by funding issues both due to SETI effort being seen as futile/feeble for the endeavour and furthermore because other areas of research such as exoplanets, habitable zones and evolutionary biology are seen to be higher priorities to yield results in this area. The limitations of SETI are discussed in Section 6.2 below.

Existing Solutions to the Fermi Paradox

Fermi’s question in 1950 has exercised the minds of many scientists and persons from a wide variety of relevant fields: science fiction authors, philosophers, historians and others over the years; and a variety of wide ranging solutions have been proposed in both scientific and popular forums and much literature exists on the topic of the Fermi Paradox. Webb (2002), a well-researched and much cited reference, is a fairly comprehensive and representative discussion of this literature fully supported by a thorough list of detailed references for each solution.

These 50 solutions have each been critically reviewed here with a view to selecting solutions/issues for consideration in developing a resolution based on the findings of this paper. A summary of the review and its outcome is given in Table 4


below.

Of these 50 solutions, the solutions that (i) are not scientific; (ii) are essentially sociological and hence speculative; (iii) cannot be taken seriously; or (iv) have already been considered under the Rare Earth Hypothesis in Section 3 above, were disregarded. The issues selected as worthy of further consideration have been grouped under (i) issues related to interstellar travel; and (ii) limitations of SETI and are discussed in Section 6.2 below.

Other Key Current Issues

6.1 Exoplanets and Habitable Zones

Ever since the first (non-pulsar) exoplanet was discovered in 1995, much focus has been on the search for Earth-like planets. Currently, known exoplanets total 4,875 of which 1,516 are confirmed and 3,356 are unconfirmed Kepler candidates (Exoplanets Web). Most of them have been discovered using the radial velocity or transit methods and hence they are biased toward planets close to their parent stars and it appears that around 17-30% of Sun-like stars host planets (Cassan et al.

2012). However, the microlensing method is able to discover stars that are further away from their parent stars and these planets are as numerous as the stars in the Milky Way. A statistical analysis of the microlensing findings (that date from 2002-7) of planets 0.5-10 AU from their stars show the following distribution: 17% Jupiter-mass planets, 52% cool Neptunes and 62% super-Earths, leading to the conclusion that stars are orbited by planets as a rule rather than the exception (Cassan et al. 2012). Taking one such system, Kepler-62, it appears that this five planet system has planets of 1.4 and 1.6 Earth radii in the habitable zone with theoretical models suggesting that both planets could be solid with either a rocky composition or with solid water in their bulk (Borucki et al. 2013). The overall finding from exoplanets discoveries is that planets are common, but planetary systems are diverse and complex in their evolution (different masses, compositions and orbital eccentricities, “hot” Jupiters that were formed elsewhere etc. ) and as yet we do not have a feel for the frequency of exoEarths with biospheres similar to Earth. To-date, only a small proportion of exoplanets has been discovered and the findings

Table 4: Review of Webb’s (2002) 50 Possible Solutions to the Fermi Paradox


are impacted by the bias arising from the search techniques used for their discovery. The hunt for exoEarths has not been underway for very long and the Copernican principle suggests that it is only a matter of time before exoEarths are found and our knowledge of both extra-terrestrial life and various astrobiological unknowns improve. This optimistic view is shared by Horner and Jones (2010) who advocate focusing on the study of the most promising exoEarths to confirm habitable planets.

6.2 Limitations of SETI - Interstellar Communications and Interstellar Travel

Other radio telescope efforts include Low Frequency Array (LOFAR) in Europe looking for the redshifted 21 cm line of neutral hydrogen which SETI could piggy-back on to evesdrop on any radio frequency interference produced by ETIs. LOFAR is estimated as being able to detect Earth-like civilisations out to a distance of 50 pc (a portion of the galaxy containing about 10^5 stars and several rocky planets) in a month of observations, while the Square Kilometer Array (SKA) radio telescope could detect signals to about 100 pc in a month of observations (Fogan and Nichol 2010). However, the development of technology over the past century or so, the reduced transmission power requirements to broadcast, and the expansion of the digital communication have reduced the extent of the radio emissions leaking from Earth and could eventually make us a “radio quiet” civilisation in the future. Monte Carlo realisation techniques to simulate growth and evolution of intelligent life in the galaxy show that civilisations that are “human” in nature and are only “radio loud’ for about 100 years can detect each other with SKA-like instrument out to 100 pc within a maximum communication time of 100 years. They also show that the probability of such civilisations accidentally detecting each other is low at 10^-7, much lower than other techniques such as Optical SETI or neutrino communication (Fogan and Nichol, 2010).

For establishing contact, whether deliberate messaging or leakage, the parallel use of equivalent communication technology is a pre-requisite. Such simultaneous technological status of ETI and Earth-life make the probability of dialogue even lower. Horvat et al. (2011) have studied the mathematical probability of technological synchronicity of our own and hypothetical ETCs and conclude that with a probability of >= 0.95 over the next 20 years, the number of detectable advanced civilisations in our galaxy, N, will need to be (i) >= 138 – 4,991 Earth-like civilisations if SETI relies solely on the fortuitous detection of leaked signals (i.e. “evesdropping”) and (ii) >= 1,497 ETCs for the probability of technological synchronicity for detecting/dialogue through deliberating messaging. According to Horvat et al., the number of ETCs required for an accidental detection could be as low as 138, once again suggesting those vast interstellar distances or sociological reasons (such as prudence or thriftiness) could be possible explanations as to why there has not yet been any evidence of ETI. Of course, it could also be possible that the number of ETCs may be smaller than this estimate of 138.

SETI is branching into other niches (e.g. Optical SETI and CETI (i.e. messaging)) in order to increase the probability of contact.

Apart from the difficulties mentioned above, there are many in-built assumptions with the SETI efforts to-date i.e. that technological evolution will encompass constructing radio telescopes, radio signals (in the frequencies chosen) would be ETC’s preferred method of communications and the sociological assumption that ETCs would wish to communicate with others in The Universe.

If the prevalence of ETCs in the galaxy is lower than the required threshold and colonisation driven contact is unlikely, then it is possible for communicating ETCs to remain ignorant of each other due to difficulties with interstellar communications. The way to circumvent this would be by permanent auto beacons


with no assurance of reciprocal communication (Smith 2009) or by interstellar travel.

The distances between the stars are simply too great to permit interstellar travel which is the simplest possible answer to Fermi’s question. Travelling at the speed of light would take 4.2 years to reach the nearest star to us, Proxima Centauri, but travelling at the speed of say Voyager 1 would take almost 73,000 years for the same journey (Webb 2002). The barrier of interstellar distance could be just too much for even a highly advanced ETC to overcome. Projects Daedalus (design of a plausible unmanned interstellar craft intended as a science probe) and Icarus are envisaging the development of rapid (velocity of >= 0.1 the speed of light) interstellar space flight (Crawford 2009). Modelling using known star systems within 40 parsecs of the solar system as percolation sites (using percolation theory), Catin (2014) concludes that ETCs could only reach the Solar System within certain maximum travel distance and the lack of ETC visits to our Solar System could be due to (i) the ETCs’ lack of desire to colonise beyond their initial colonisation locations; or (ii) because despite these ETCs having the technology to visit a number of other systems, their vessels cannot travel sufficient distance to reach our local cluster of stars; or (iii) that they are statistically unlikely to reach us. Interstellar travel ideas include rockets, fusion ramjets, laser sails, gravity assists, travel through wormholes, nano probes, generation ships and Bracewell-von Neumann self-reproducing probes etc. The current technology on Earth is insufficient for interstellar travel.

7. Where is everybody?

The examination of the various facets of the Fermi Paradox above does not lead to an obvious, clear-cut conclusion because there are strengths and weaknesses within all of the arguments and possible solutions. This is why Fermi Paradox remains unresolved 60+ years later.

At the very heart of the debate is the question whether Earth-life is either rare or even unique and hence ETI is either non-existent for all practical intents and purposes and the likelihood of detecting them is close to zero. So any resolution of the Fermi Paradox boils down to one’s take on this critical issue and then the resolution of Fermi Paradox either points to the Rare Earth Hypothesis or provides plausible explanations for the lack of contact with ETI to-date.

This topic is as much philosophical as scientific and one’s view on the likely existence or otherwise of ETI often seems to depend on one’s belief system and personal preference for the Occam’s Razor approach or for the Copernican Principle. With this in mind, a quick and simple opinion poll was undertaken with students of the Astrobiology and Origins of Life university course, who had spent the previous 9 weeks reflecting on the various astrophysics, planetary science and evolutionary biological issues that are very relevant to this topic. Of the 28 persons (including the tutor) polled, 14 responded and the responses are summarised in Table 5 below.

Table 5: Responses to the Opinion Poll on the existence of detectable ETIs

Believers in ETI 7

Non-believers in ETI 4

Fence sitters 3

Source: Brito 2014

Despite being totally non-scientific and non-representative by any measure, the above responses add weight to the view that the debate on the Fermi Paradox will continue at not only at the scientific level but also at the popular level until more and more scientific research/exploration provide better information on the biological factors of the Drake Equation and technological advancements make SETI efforts more economic and increase its viability in looking for ETI. The absence of detection can never prove the non-existence of ETIs so the only way this matter can be conclusively settled is when there is a successful detection of ETI. Such research/exploration is what scientific endeavours are all about.

8. Are we a cosmic fluke?

Copernicus’s theoretical prediction was eventually proved when Galileo looked through his telescope. Albert Einstein’s theory of relativity and predictions relating to the transit of Mercury was proved years later with observations and his work necessitated a refinement to Isaac Newton’s breakthrough theory of gravity. This is how science develops.

The Rare Earth Hypothesis has weaknesses and the Drake Equation estimates will improve as our knowledge of some of the remaining variables improves. However, the sociological variables are likely to remain speculative until the undisputable resolution of the Fermi Paradox through detection of ETI without which the Fermi Paradox will remain unresolved. For the present, based on the above findings and balancing the various arguments, this paper offers the difficulties of interstellar communications and interstellar travel in an ever expanding universe as the likely resolution to the Fermi Paradox. However, the true answer to the Fermi Paradox will only be known when either interstellar dialogue take place or when interstellar travel provides us with new and reliable information.

It seems unlikely that we are a cosmic fluke - the sole sentient species alone in the incalculably immense universe. It was just over 400 years ago that Galileo looked at the heavens through the telescope to prove Copernicus right (i.e. the Earth was not at the centre of the Solar System) and, since then, we have come an incredibly long way in understanding our universe. Cocconi and Morrison’s (1959) concluding words “The probability of success is difficult to estimate; but if we never search, the chance of success is zero” holds true to this day and the search must continue. It seems appropriate to conclude with the toast offered by Otto Struve at the end of the Green Bank Conference as reported by Billings (2013) - “To the value of L (lifetime of a technologically advanced civilisation). May it prove to be a very large number”.


References:

Billings, L., 2013, Five Billion Years of Solitude: The search for life among the stars (Penguin Group, New York) Bogonovich, M., 2011, International Journal of Astrobiology 10 (2): 113-122 (2011) Borucki, W. J., et al., 2013, Science 340, 587 Brito, N., 2014, Voluntary Opinion Poll of the Archaea Group of the 2014 Astrobiology and Origins of Life on their belief in ETI (31 October – 8 November)

Cassan, A. et al., 2012, Nature 481, 167-169

Catin, D., 2014, arXIV: 1404.02 04v1

Cocconi, G. and Morrison, P., 1959, Nature, Volume 184, 844

Conway Morris, S, 2005, Life's Solution: Inevitable Humans in a Lonely Universe (Cambridge, UK: Cambridge University Press) Crawford, I. A., 2009, Paper on the Astronomical, Astrobiological and Planetary Science case for Interstellar Flight presented at the British Interplanetary Society “Project Daedalus – Three Deacdes on” Symposium Drake, F., 2013, International Journal of Astrobiology 12 (3): 173-176

ESA Web: http://www.esa.int/Our_Activities/Space_Science/Herschel/How_many_stars_are_there_in_the_Universe (accessed 15 November 2014)

Exoplanets Web: exoplanets.org/ (accessed 19 November 2014)

Fogan, D.H., 2009, International Journal of Astrobiology 8 (2): 121-131 (2009)

Fogan, D.H., and Nichol, R.C., 2010, International Journal of Astrobiology 10 (2): 77-81 (2011)

Fogan, D.H. and Rice, R., 2010, International Journal of Astrobiology 9 (2): 73-80 (2010)

Freedman, Geller & Kaufmann, 9th edition, 2011, Universe (New York: W.H. Freeman & Co.)

Horner, J. and Jones, B.W., 2010, International Journal of Astrobiology 9 (4) 273-291 Horvat, M., Nakic, A. and Otocan, I., 2011, International Journal of Astrobiology 11 (1):51-59 (2012) Jones, B.W., 2008, International Journal of Astrobiology, 7 (3&4), 279-292

Jones, E. M., 1985, LA-10311-MS, UC-34B, Los Alamos National Library, New Mexico

Lazio, T. J. W., 2009, Proceedings of Science, PoS (PRA 009) 058

Newmn, W.I. and Sagan, C, 1981, ICARUS 46, 293-327

OED Web 1: http://www.oxforddictionaries.com/definition/english/anthropic-principle (accessed 16 November 2014) OED Web 2: http://www.oxforddictionaries.com/definition/english/Occam's-razor (accessed 16 November 2014) Rothery, D.A., Gilmour, I. and Sephton, M.A., 2011, An Introduction to Astrobiology, 2nd edition (Cambridge University Press) Shklovski, I.S. and Sagan, C., 1968, Intelligent Life in the Universe (Holden-Day, Inc. San Francisco)

Shuch, H. P., 2011, in Searching for Extraterrestrial Intelligence – SETI Past, Present and Future (Praxis Publishing, Chichester, U.K.) Sky and Telescope Web: http://www.skyandtelescope.com/astronomy-resources/how-many-galaxies/ (accessed 15 November 2014)

Smith, R.D., International Journal of Astrobiology 8 (2): 101-105

Ward, P. D., 2005, Life as We Do Not Know It – The NASA search for (and synthesis of) alien life (Penguin Books) Ward, P. D. and Brownlee, D., 2000, Rare Earth: Why Complex Life is Uncommon in the Universe (Copernicus Books) Webb, S., 2002, If the Universe Is Teeming with Aliens Where Is Everybody?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life (Copernicus Books)

Eta Carinae's Stars Clash From RASNZ Newsletter by Alan Gilmore

Article by Kelly Beatty originally from http://www.skyandtelescope.com/astronomy‐news/

E mbedded in the lovely Carina Nebula, one of the great

observing gems of the far-southern sky, Eta Carinae is

the most massive, most luminous star within 10,000 light-years of us. (It's 7,500 light-years distant.) Astronomers now

believe it's actually a binary star whose gigantic primary has

roughly 90 times the Sun's mass and outshines it by 5

million times. Less is known about the secondary, but it too

is thought to be enormous, with perhaps 30 solar masses and a million times the Sun's luminosity.

Eta Carinae erupted violently in 1843, ejecting perhaps 10

Sun's worth of mass - a truly titanic blast that would have

destroyed a lesser star. This "erratic stellar monster," as one

researcher dubbed it, briefly became the second-brightest

star in the night sky. Today astronomers see the results of that outburst as an expanding two-lobed shell called the

Homunculus Nebula.

More recently, space observatories found that Eta Carinae

creates strong X-ray outbursts every 5.5 years. This happens

whenever the paired stars are closest in their highly elongated orbit and separated by only about 225 million km

- roughly Mars's distance from the Sun.

These periodic encounters are not just hi-and-bye affairs. It's

more a clash of the titans. The larger star's extreme

luminosity is driving dense stellar winds that carry off a Jupiter's worth of mass every year at roughly 400 km per

second. The secondary also creates an intense outflow, one

that's less dense yet has six times higher velocity.

Computer simulations by Thomas Madura (NASA Goddard

Space Flight Center) and others suggest that the secondary's

flow carves out a cavity in the primary's slower, denser wind - much as a moving boat creates a wake around it.

Nothing much happens when the two stars are widely


separated. But when closest to each other, at periastron, the

two flows collide violently, creating a shock boundary that

heats the gas to tens of millions of degrees - hot enough to generate a torrent of X-rays that build gradually over many

months and then drop off precipitously as the stars start to

separate.

Madura and others at NASA's Goddard Space Flight Center

have created a dramatic recreation of how the winds interact when they slam together that's worth watching.

See it at the link below.

NASA's Swift spacecraft captured the most recent X-ray

flare-up last July, and it was stronger than previous

outbursts recorded in 1995, 2003, and 2009 by the Rossi X-

ray Timing Explorer. Moreover, the tailing off of the emission spike was different too. One of the two stars'

winds must have changed over time - but which?

Fortunately, observers could sort it out using a blue-light

emission from ionized helium at 468.6 nanometres. As

Mairan Teodoro (Western Michigan University) explains, the

X-rays are produced on the side of the shock zone nearest

the secondary. But the helium emission comes from the

primary's dense slow wind - a crucial difference. At the recent meeting of American Astronomical Society, Teodoro

presented 22 years of spectroscopic observations of Eta

Carinae gathered using a worldwide network of telescopes.

(Amateurs played a crucial role in this campaign, by the

way.) He says that the helium emission, first noted during 2003's periastron, has been steady to within about 20%. So

the varying X-ray flux must be due to changes in the

secondary star and its high-speed wind.

Frankly, astronomers know very little about the secondary -

even its mass is something of a guesstimate. As Madura

concedes, "We actually still don't know what the secondary star is, and that's one of the reasons why we're doing all

this work." In fact, a big question mark remains about the

1843 eruption. "Everyone thinks it's the more massive star

that threw off the mass [in 1843] to form the Homunculus

Nebula," he says, "but to be honest we don't even know which star had the eruption."

Explanation: If you're looking for something to print with that new 3D printer, try out a copy of the Homunculus Nebula. The dusty, bipolar cosmic cloud is around 1 light-year across but is slightly scaled down for printing to about 1/4 light-nanosecond or 80 millimeters. The full scale Homunculus surrounds Eta Carinae, famously unstable massive stars in a binary system embedded in the extensive Carina Nebula about 7,500 light-years distant. Between 1838 and 1845, Eta Carinae underwent the Great Eruption becoming the second brightest star in planet Earth's night sky and ejecting the Homunculus Nebula.

Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova.

The new 3D model of the still expanding Homunculus was created by exploring the nebula with the European Southern Observatory's VLT/ From APOD


C onfirming earlier suspicions, a joint analysis of data from the European Space Agency´s Planck satellite and the ground-based

BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves. (See Newsletter No. 166, Item 8.)

The universe began about 13.8 billion years ago and evolved from an extremely hot, dense and uniform state to the rich and complex cosmos of galaxies, stars and planets we see today. An extraordinary source of information about The Universe´s history is the cosmic microwave background, or CMB, the legacy of light emitted only 380,000 years after the Big Bang. ESA´s Planck satellite observed this background across the whole sky with unprecedented accuracy, and a broad variety of new findings about the early universe has already been revealed over the past two years.

But astronomers are still digging ever deeper in the hope of exploring even further back in time: they are searching for a particular signature of cosmic `inflation´ -- a very brief accelerated expansion that, according to current theory, The Universe experienced when it was only the tiniest fraction of a second old. This signature would be recorded in gravitational waves, tiny perturbations in the fabric of space-time, that astronomers believe would have been generated during the inflationary phase.

Interestingly, these perturbations should leave an imprint on another feature of the cosmic background: its polarization. When light waves vibrate preferentially in a certain direction, we say the light is polarized. The CMB is polarized, exhibiting a complex arrangement across the sky. This arises from the combination of two basic patterns: circular and radial (known as E-modes), and curly (B-modes).

Different phenomena in The Universe produce either E- or B-modes on different angular scales. Identifying the various contributions requires extremely precise measurements. It is the B-modes that could probe The Universe´s early inflation. But this unique record of the very early universe is hidden in the polarization of the CMB, which itself only represents only a few percent of the total light.

Early 2014 the BICEP2 team presented results based on observations of the polarized CMB on a small patch of the sky performed in 2010-12 with their microwave telescope at the South Pole. The team also used preliminary data from another South Pole experiment, the Keck Array. They found curly B-modes in the polarization observed over stretches of the sky a few times larger than the size of the full Moon. The BICEP2 team presented evidence favouring the interpretation that this signal originated in primordial gravitational waves, sparking an enormous response in the academic community and general public.

However interstellar dust in our galaxy can produce a similar effect. The Milky Way is pervaded by a mixture of gas and dust shining at similar frequencies to those of the CMB. This foreground emission affects the observation of the most ancient cosmic light. Very careful analysis is needed to separate the foreground emission from the

cosmic background. Critically, interstellar dust also emits polarized light, thus affecting the CMB polarization as well.

The BICEP2 team relied on models for galactic dust emission that were available at the time. These seemed to indicate that the region of the sky chosen for the observations had dust polarization much lower than the detected signal. The two ground-based experiments collected data at a single microwave frequency, making it difficult to separate the emissions coming from the Milky Way and the background.

The Plank satellite observed the sky in nine microwave and sub- millimetre frequency channels, seven of which were also equipped with polarization-sensitive detectors. By careful analysis, this multi- frequency data can be used to separate the various contributions.

The BICEP2 team had chosen a field where they believed dust emission would be low, and thus interpreted the signal as likely to be cosmological. However, as soon as Planck´s maps of the polarized emission from galactic dust were released, it was clear that this foreground contribution could be much higher than previously expected. In fact, in September 2014, Planck revealed for the first time that the polarized emission from dust is significant over the entire sky, and comparable to the signal detected by BICEP2 even in the cleanest regions.

So, the Planck and BICEP2 teams joined forces. They combined the satellite´s ability to deal with foregrounds, using observations at several frequencies, with the greater sensitivity of the ground-based experiments over limited areas of the sky, thanks to their more recent, improved technology. By then, the full Keck Array data from 2012 and 2013 had also become available. This joint work showed that the detection of primordial B-modes was not clear once the emission from galactic dust is removed.

Another source of B-mode polarization, dating back to the early universe, was detected in this study, but on much smaller scales on the sky. This signal, first discovered in 2013, is not a direct probe of the inflationary phase but is induced by the cosmic web of massive structures that populate The Universe and change the path of the CMB photons on their way to us. This effect is called `gravitational lensing,´ since it is caused by massive objects bending the surrounding space and thus deflecting the trajectory of light much like a magnifying glass does. The detection of this signal using Planck, BICEP2 and the Keck Array together is the strongest yet.

As for signs of the inflationary period, the question remains open. The joint study sets an upper limit on the strength of gravitational waves from inflation. They might have been generated at the time but at a level too low to be confirmed by the present analysis. The analysis shows that the amount of gravitational waves can probably be no more than about half the observed signal. The gravitational wave signal could still be there, and the search is definitely on.

-- From a European Space Agency press release forwarded by Karen Pollard.

Inflation Signature Not Found in Plank Analysis From RASNZ Newsletter by Alan Gilmore


F ilm Night February was very well

attended and featured a documentary called "Which Universe are

we in". It was about the idea of

multiverse of infinite proportions.

Professor Max Tegmark of the Massachusetts Institute of Technology

starts the argument by asking how you

define the end of space? Is there a sign saying "space ends here"?!

Hugh Everett the American physicist

early theories that were, at the time,

received by the physics community with scorn, were covered. He proposed the

many-worlds interpretation (MWI) of

quantum physics, which he termed his "relative state" formulation.

The double slit experiment and the

concept of external inflation were

discussed. The idea that over infinite time very possibility will happen. Ideas

about matter being in two places at once

with the observer only being able to experience one and that these divisions

into two happen many times over were

explained and how his leads to ideas of

parallel universes with many different

structures.

Professor Laura Mersini-Houghton of the University of North Carolina combined

String Theory and Quantum Theory to

come up with a number of anomalies that could be observed to validate the

multiverse idea , which suffers from the

problem of difficult to prove or disprove

by observation or experimentation.

The main film was followed by the December Sky at Night show entitled

"Pillar of Creation" that was about

nebula and their role in star formation.

Next Film Night is on Monday March 23rd, 8pm at Stardome and features a

Documentary entitled "10 Things you

didn't know about Volcanoes".

This film examines some of history's

most famous volcanic eruptions and

what caused them. It also looks at the

nature of the Earth's Crust and Plate Tectonics. It is followed by a Sky at

Night show on " What UFOs have done

for us".

Which Universe are we in? Film Night Report By Gavin Logan

Professor Max Tegmark using lego to explain the multiverse concept.

Audience enjoying the first film night for 2015

The two faces of Mars: Moon‐sized celestial object crashed into south pole From Science Direct

T he two hemispheres of Mars are more different from any other planet in our solar system. Non-volcanic, flat lowlands

characterise the northern hemisphere, while highlands punctuated by countless volcanoes extend across the southern hemisphere. Although theories and assumptions about the origin of this so-called and often-discussed Mars dichotomy abound, there are very few definitive answers. ETH Zurich geophysicists under Giovanni Leone are now providing a new explanation. Leone is the lead author of a paper recently published in the journal Geophysical Research Letters.

Using a computer model, the scientists have concluded that a large celestial object must have smashed into the Martian south pole in the early history of the Solar System. Their simulation shows that this impact generated so much energy that it created a magma ocean, which would have extended across what is today's southern hemisphere. The celestial body that struck Mars must have been at least one-tenth the mass of Mars to be able to unleash enough energy to create this magma ocean. The molten rock eventually solidified into the mountainous

highlands that today comprise the southern hemisphere of Mars.

Volcanic activity over three billion years In their simulation, the researchers assumed that the celestial body consisted to a large degree of iron, had a radius of at least 1,600 kilometres, and crashed into Mars at a speed of five kilometres per second. The event is estimated to have occurred around 4 to 15 million years after the Red Planet was formed. Mars' crust must have been very thin at that time, like the hard, caramelised surface of a crème brûlée. And, just like the popular dessert, hiding beneath the surface was a liquid interior.

When the celestial object impacted, it added more mass to Mars, particularly iron. But the simulation also found that it triggered strong volcanic activity lasting three billion years. Around the equator in particular, numerous mantle plumes were generated as a consequence of the impact, which migrated to the south pole where they ended. Mantle plumes are magma columns that transport liquid material from the


mantle to the surface.

In the model, the researchers found that activity on Mars died down after around three billion years, after which time the Red Planet experienced neither volcanic activity nor a magnetic field -- this is consistent with observations and measurements.

Volcanic activity and topography modelled under realistic conditions Earlier theories posited the opposite, namely that there must have been a gigantic impact or many smaller strikes against the northern hemisphere. The most important theory about the origin of the Mars dichotomy was formulated by two American researchers in 1984 in an article in the journal Nature. They postulated that a large celestial object struck the Martian north pole. In 2008 a different team revived this idea and published it once again in Nature.

This theory did not convince Leone: "Our scenarios more closely reflect a range of observations about Mars than the theory of a northern hemisphere impact," states Leone. The volcanoes on Mars are very unevenly distributed: they are common and widespread on the southern hemisphere, but are rare and limited to only a few small regions in the northern hemisphere. "Our model is an almost identical depiction of the actual distribution of volcanic identity," asserts Leone. According to the researcher, no other model has been able to portray or explain this distribution before.

Their simulation was also able to reproduce the different topographies of the two hemispheres in an extremely realistic manner, says Leone. And he goes on to explain that the model -- depending on the composition of the impact body chosen -- is a virtually perfect representation of the size and shape of the hemispheres. One condition, however, is that the celestial body impacting Mars consist of 80 per cent iron; when the researchers simulated the impact with a celestial body made of

pure silicate rock, the resulting image did not correspond to the reality of the dichotomy.

Magnetic field tipped the balance

Lastly, the model developed by the ETH researchers confirmed the date on which the magnetic field on Mars ceased to exist.

The date calculated by the model corresponds to around 4.1

billion years ago, a figure previously proven by other scientists.

The model also demonstrates why it ceased: a sharp decrease in heat flow from the core into the mantle and the crust in the first

400 million years after the impact. After a billion years, the heat

flow was only one-tenth its initial value, which was too low to maintain even the volcanism. The model's calculations closely

match previous calculations and mineralogical explorations.

The volcanic activity is related to the heat flow, explains Leone,

though the degree of volcanic activity could be varied in the simulation and influenced by the strength of the impact. This,

he states, is in turn linked to the size and composition of the

celestial object. In other words, the larger it is, the stronger the volcanic activity is. Nevertheless, after one billion years the

volcanic vents were extinguished -- regardless of the size of the

impact.

It has become increasingly clear to Giovanni Leone that Mars has always been an extremely hostile planet, and he considers it

almost impossible that it ever had water. "Since the beginning

of time, this planet was characterised by intense heat and volcanic activity, which would have evaporated any possible

water and made the emergence of life highly unlikely," asserts

the planet researcher.

Mars has two differently shaped hemispheres: the lowlands of the northern hemisphere and the volcanic highlands (yellow to red regions) of the southern hemisphere. A "giant impact" on the southern pole is suspected to be the reason for this. Credit: MOLA Science Team


Society Astronomical Equipment for Rent

The Society has a wide variety of equipment available for rental to members, from beginner friendly Dobsonian telescopes, through to more advanced computerised GOTO systems. All rental equipment is of high quality and regularly maintained.

Rental periods are normally in 4 week blocks, but other arrangements may be available if you have a specific requirement. Full training and support is given for all equipment, including advice if equipment is suitable for your needs, or experience level.

Current rental equipment includes:

* 200mm Astronz Dobsonian Telescopes ($10/week)

* Celestron Nexstar 5 127mm Schmidt Cassegrain Alt/Az GOTO Telescope ($12.50/week)

* iOptron Minitower multipupose Alt/Az Mount with Celestron C5 127mm OTA ($15/week)

* Meade 90mm Achromatic Refractor ($7.50/week)

Also, newly added to the rental stock

* Coronado PST 40mm Hydrogen‐Alpha Solar Telescope ($12.50/week)

* iOptron ZEQ25 Computerised Equatorial Mount

We are often adding items to our rental equipment, and we're really keen to hear what other items may be useful to members ‐ any ideas, or for any information regarding availability or how to rent equipment, please contact Steve Hennerley on 027 245 6441

International Sidewalk Astronomy Night

This year the ISAN event will be held on March 28.

“Started in 2007, International Sidewalk Astronomy Night has become a regular event for sidewalk astronomers worldwide. Most

of us are out on the sidewalk many nights each year sharing views of the night sky to the public, and one night a year we

celebrate this activity and make it an international event. Many people held their first sidewalk event during ISAN and have

continued doing sidewalk observing. That is our goal, to get as many people out with a scope as possible because once they do,

chances are they will like doing it and continue. In this way, maybe someday we can show all the people of this planet the

Universe in which they live.” (From ISAN web page)

Please visit the link below for more details.

http://www.sidewalkastronomers.us/ or https://www.facebook.com/Sidewalkastro

Register your interest on the web page and/or Facebook:

We will go when the weather is suitable. You can register your availability and specify: “according to weather conditions”.

From previous experience:

- Groups 2-4 peoples with 1-2 telescopes.

- Choose a crowded area such as a: mall, park, fast-foods, bus station, on a large footpath, in a scenic view areas (for example on top of Mount Eden, Mission Bay)…

- Do NOT put the telescopes in a CARPRK!

- Take pictures and approximate the number visitors.

- Write a short report and specify the name of Auckland Astronomical Society and specify if you are an RASNZ member.

For more details or support contact Danut Ionescu at [email protected]


The Evening Sky in March 2015 By Alan Gilmore

T wo bright planets light up the twilight sky. Silver Venus appears low in the west. Golden Jupiter appears in the north-east. Venus soon sets, but Jupiter stays in the northern sky all night, setting in the northwest in the morning hours. Bright stars are

overhead and down into the southeast sky.

Jupiter is the biggest planet by far. Its mass is greater than all the other planets put together. In a telescope it shows parallel stripes. These are zones of warm and cold clouds, made narrow by Jupiter's rapid rotation. Any telescope shows Jupiter's disk with its four bright 'Galilean' moons lined up on either side. They are roughly the size of our Moon. Sometimes one or two moons can be seen in binoculars, looking like faint stars close to the planet. Io, the smallest and closest to Jupiter, has massive volcanoes. The other moons have crusts of ice, some with oceans beneath, around rocky cores. Jupiter is 680 million km from us in March. The Moon will be near Jupiter on March 3rd and 30th.

Northwest of overhead is Sirius the brightest star in the sky. It is fainter than star-like Venus and Jupiter. Southwest of the zenith is Canopus, the second brightest star. Below Sirius are Rigel and Betelgeuse, the brightest stars in Orion. Between them is a line of three stars: Orion's belt. To southern hemisphere star watchers, the line of three makes the bottom of 'The Pot'. Orion's belt points down and left to a V-shaped pattern of stars. These make the face of Taurus the Bull. The orange star is Aldebaran, Arabic for the eye of the bull. Continuing the line from Orion down and left finds the Pleiades or Matariki star cluster.

Sirius is the brightest star in the sky both because it is relatively close, nine light years* away, and 23 times brighter than the Sun. Rigel, above and left of Orion's belt, is a bluish supergiant star, 40 000 times brighter than the Sun and much hotter. It is 800 light years away. Orange Betelgeuse, below and right of the line of three, is a red-giant star, cooler than the Sun but much bigger and 9000 times brighter. It is 400 light years from us. The handle of "The Pot", or Orion's sword, has the Orion Nebula at its centre; a glowing gas cloud many light-years across and 1300 light years away.

Near the north skyline are Pollux and Castor marking the heads of Gemini the twins. Left of Jupiter is the star cluster Praesepe, marking the shell of Cancer the crab. Praesepe is also called the Beehive cluster, the reason obvious when it is viewed in binoculars. The cluster is some 500 light years from us.

Crux, the Southern Cross, is in the southeast. Below it are Beta and Alpha Centauri, often called 'The Pointers'. Alpha Centauri is the closest naked-eye star, 4.3 light years away. Beta Centauri, like most of the stars in Crux, is a blue-giant star hundreds of light years away. Canopus is also a very luminous distant star; 13 000 times brighter than the Sun and 300 light years away.

The Milky Way is brightest in the southeast toward Crux. It becomes broader lower in the southeast toward Scorpius. Above Crux the Milky Way can be traced to nearly overhead where it fades. It becomes very faint in the north, right of Orion. The Milky Way is our edgewise view of the galaxy, the pancake of billions of stars of which the Sun is just one. We are 30,000 light years from the galaxy's centre.

The Clouds of Magellan, LMC and SMC are high in the south sky, easily seen by eye on a dark moonless night. They are two small galaxies about 160 000 and 200 000 light years away.

Saturn rises in the southeast before midnight at the beginning of March. It is on the lower end of a curve of stars making the Scorpion's claws. To its right, slightly higher in the sky and fainter, is orange Antares, marking Scorpio's heart. By the end of the month, Saturn is up around 10 p.m. A telescope magnifying 20x shows Saturn's rings. Saturn is 1430 million km away in mid-March. The Moon is by Saturn on the 12th.

Mercury (not shown) ends its best morning sky appearance of the year during March. At the beginning of the month it rises around 5 a.m., a little south of due east. It is the brightest 'star' in that part of the sky. By the end of the month it is rising at 7 a.m. less than an hour before the Sun. It is tiny in a telescope.

The Larger Asteroids

Ceres is a morning object in Sagittarius with magnitude 9.2. On the 1st it will be just over 6° from Pluto and rise 4 minutes later. On

the 31st Ceres crosses into Capricornus, it then rises about 1.20 am.

uno is an evening object in Cancer during March. It loses brightness steadily during the month as its distance from the Earth increases. Its magnitude ranges from 8.8 in the 1st to 9.6 on the 31st.

Vesta is in Capricornus at the start of March. It moves into Aquarius on the 22nd. On the morning of the 16th it will be just over a

quarter degree, half the diameter of the full Moon, to the left of the star delta Cap, magnitude 2.9. This should make Vesta easy to locate in binoculars. About 6am would be a good time to look for the two. Don't confuse Vesta with an 8.8 magnitude star a little to

its right.

Iris is in Leo and at opposition at the beginning of the month. Its magnitude will then be 8.9. It moves into Sextans on the 7th, and fades to magnitude 9.5 by the 31st.

Notes by Alan Gilmore, University of Canterbury's Mt John Observatory, P.O. Box 56, Lake Tekapo 7945, New Zealand.

www.canterbury.ac.nz


The Night Sky for March 2015


Auckland Astronomical Society Inc, P O Box 24‐187, Royal Oak, Auckland 1345, New Zealand

Email [email protected]

Journal [email protected]

Website www.astronomy.org.nz facebook.com/AuckAstroSoc

Membership inquiries contact Andrew Buckingham at [email protected] or by phone on (09)‐473‐5877 or by mobile on 027‐246‐2446

Society Contacts

President Bill Thomas (09) 478 4874

Vice‐President Grant Christie (09) 636 3437

Treasurer & Andrew Buckingham (09) 473 5877 Membership

Secretary Gavin Logan 021 144 1055

Curator of Graham Beazley (09) 537 1313 Instruments

Telescope Hire Steve Hennerley 027 245 6441

Librarian Jerina Grewar (09) 444‐5086

Journal Editors Clive Bolt (09) 534 2946

Shaun Fletcher (09) 557 8686

Milina Ristic 029 912 4748

Council Jonathan Green (09) 415‐7284

Council Bernie Brenner 09) 445 3293

Council David Britten (09) 846 3657

Council/Events Oana Jones (09) 634 1409

The 2014 Council

Solar System Events March 2015 From the RASNZ Website

• apogee: Furthest point in the orbit of a body orbiting the Earth

• conjunction: Two astronomical objects are 'lined up' (have the same right ascension) when viewed from Earth

• declination: 'Latitude' for celestial objects. The distance in degrees above (north) or below (south) the celestial equator. • perigee: Nearest point in the orbit of a body orbiting the Earth

March 3 Jupiter 5.3 degrees north of the Moon

March 4 Regulus 3.8 degrees north of the Moon Venus 0.1 degrees north of Uranus

March 5 Moon at apogee Moon full

March 9 Spica 3.3 degrees south of the Moon

March 11 Mars 0.3 degrees north of Uranus

March 12 Saturn 2.2 degrees south of the Moon

March 13 Moon last quarter

March 14 Moon southern most declination (-18.3 degrees) Saturn stationary

March 15 Pluto 3.1 degrees south of the Moon

March 18 Mercury 1.5 degrees south of Neptune Neptune 3.5 degrees south of the Moon

March 19 Mercury 4.9 degrees south of the Moon Moon at perigee

March 20 Moon new Eclipse Equinox

March 21 Uranus 0.1 degrees south of the Moon Occn Mars 0.9 degrees north of the Moon Occn

March 22 Venus 2.8 degrees north of the Moon

March 25 Aldebaran 0.9 degrees south of the Moon Occn

March 26 Moon northern most declination (18.2 degrees)

March 27 Moon first quarter

March 30 Jupiter 5.4 degrees north of the Moon

March 31 Regulus 3.9 degrees north of the Moon

march society journal · a 2013 study by astronomers using the hubble space telescope estimated...

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