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News and Reviews in
Manhattanhenge
Astronomy & Geophysics Star factories
October 2013 • Vol. 54 • Issue 5
Rapid core dynamics
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Understanding
galaxy morphology
Advancing
Astronomy and
Geophysics
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The Ballet of the Planets
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Contents
News and Views
NEWS AND REVIEWS IN
4 Editorial: Zoo goes zoom • Comet ISON keeps
ASTRONOMY & GEOPHYSICS observers guessing • Are we martians? • Seeing the
future of the Sun • ALMA takes aim at jets • Stars
Astronomy & Geophysics publishes news reviews
and comment on topics of interest to astronomers with clouds of lead • Lazarus comets lurk in
and geophysicists. Topical material is preferred.
Publication will be as fast as is compatible with asteroid belt • Perseids popular at Gemini South •
referees’ and authors’ responses. Contact the Editor
or see http://www.ras.org.uk for further information. Astronomy for peace • Einstein@Home discovers
Editor: Sue Bowler 24 pulsars • Citizen science targets volcanoes •
School of Physics and Astronomy,
University of Leeds, Leeds LS2 9JT, UK Chandra marathon shows black hole habits •
Tel: +44 (0)113 343 6672. Fax: +44 (0)113 343 3900
Email: s.bowler@leeds.ac.uk More water found on the Moon.
Management Board
Chair: Ian Crawford Birkbeck College, Univ. of London
8 Mission update: WISE, Kepler, Voyager, Cassini.
Curiosity watches the transit of Phobos, p8
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Pamela Mortimer RAS
Robert Massey RAS
Mike Cruise RAS Features
Editorial Advisors
Andrew Ball Noordwijk
Tom Boles Coddenham
10 The physics of mining in space
Allan Chapman Oxford University Kian Raafat, Jordan Burnett, Thomas Chapman
Roger Davies Oxford University
Mike Edmunds University of Wales, Cardiff and Charles S Cockell ask: what’s different about
Jane Greaves University of St Andrews
Mike Hapgood Rutherford Appleton Laboratory mining off Earth?
Richard Holme University of Liverpool
Ian Howarth University College London
David Hughes Sheffield
Katherine Joy University of Manchester
13 Astronomical applications of the
Margaret Penston IoA, Cambridge
Claire Parnell University of St Andrews quincuncial map projection
Roberto Trotta Imperial College London
Althea Wilkinson University of Manchester D B Taylor and S A Bell make the case for
The Council of the RAS
C S Peirce’s little-used but practical quincuncial
Burlington House, Piccadilly,
astronomical map projection.
London W1J 0BQ
Tel: (0)20 7734 4582 or 3307
Fax: (0)20 7494 0166 16 Morphology in the era of large surveys 5
What is different about mining in space? p10
Email: info@ras.org.uk
Web: http://www.ras.org.uk Chris Lintott and Karen Masters review progress
Opening Hours in understanding galaxy morphology, as discussed 19.2
(Monday to Friday)
Offices: 9.30–17.00 at this RAS meeting
Library: 10.00–17.00
Staff Contacts
Executive Secretary
20 Promoting SETI in the UK
19
Pamela Mortimer pm@ras.org.uk
RAS Communications Officer
Alan Penny reports on a meeting of UK academics
log H2 dz (cm)
active in SETI, and the formation of the UK SETI
y (kpc)
Robert Massey rm@ras.org.uk 0
Research Network to promote UK academic work.
18.8
23 Aeromagnetic data interpretation
Produced for the RAS by Oxford University Press,
Great Clarendon Street, Oxford OX2 6DP, UK Alan Reid reports on the BGA seminar on
Tel: +44 (0)1865 353895. Email: astrog@oup.com
aeromagnetic data interpretation. 18.6
This journal is available online at:
http://www.astrogeo.oxfordjournals.org
Star formation and giant molecular clouds, p24
Subscriptions: http://oxfordjournals.org/our_
24 Giant molecular clouds: –5
journals/astrogeo/access_purchase/price_list.html
star factories of the galaxy –5 0
x (kpc)
5
Design and production:
Paul Johnson http://www.higgs-boson.com Clare Dobbs discusses star formation in galaxies and
Printed by C.O.S. Printers Pte Ltd, Singapore the sites of star formation: giant molecular clouds.
ISSN 1366-8781 (print), ISSN 1468-4004 (online)
©2013 RAS and individual contributors. All rights 31 Manhattanhenge
reserved. Authorization to photocopy items for
internal or personal use, or the internal or personal Paul Murdin recounts his experience of an
use of specific clients, is granted by the RAS for
libraries and other users registered with the
astronomical occasion that gets New Yorkers
Copyright Clearance Center Transactional Reporting
Service, provided that the base fee of $15 per copy
talking about the sky.
is paid directly to CCC (http://www.copyright.com).
Special requests should be addressed to the Editor.
Disclaimer The contents and views expressed in
32 Rapid dynamics of the Earth’s core
A&G are the responsibility of the Editor. They do not Changes in the magnetic field allow us to probe
represent the views or policies of the RAS or Oxford
University Press, except where specifically identified the Earth’s iron core. Grace Cox and William
as such. While great care is taken to provide accurate
and helpful information and advice in the journal, the Brown review how observations, modelling and
RAS, its Council and the Editor accept no responsibility
for errors or omissions in this or other issues. theory combine.
A&G (ISSN 1366-8781) is published bimonthly.
A&G is distributed by Mercury Media Processing,
Cover: Arp142, a pair of galaxies also known as
1634 E. Elizabeth Ave, Linden, NJ 07036, USA. Obituaries
Periodicals postage paid at Rahway, NJ and at the Penguin Galaxy, owes its shape to a galactic
additional entry points. US Postmaster: send address
changes to A&G, c/o Mercury Media Processing, 38 Margherita Hack. collision. It was chosen as a cover image by
1634 E. Elizabeth Ave, Linden, NJ 07036, USA.
Galaxy Zoo volunteers after nomination by
Society News Alice Sheppard. Find out more about galaxy
morphology in the article on pages 5.16–5.19.
39 Apply for RAS research fellowships • Awards • (NASA, ESA and the Hubble Heritage Team
New booklet promotes astronomy • New Fellows. [STScI/AURA])
A&G • October 2013 • Vol. 54 5.3
News
Editorial Comet ISON keeps observers guessing
Zoo goes zoom Speculation about whether or not a coordinated observing campaign to
Sue Bowler, comet C2012 S1 ISON will live up track the comet.
Editor to its “comet of the century” billing As it passes Mars at a distance of
has continued as it became visible 0.07 au, Mars Science Laboratory
The again in August. Early observations researchers will observe it with the
Zooniverse including the first image, taken by HiRISE camera, designed for map-
is expanding. amateur observer Bruce Gary of ping the surface of Mars. While the
Citizen Arizona, suggested that it had not camera is not ideal for imaging com-
science, brightened as much as anticipated ets, because it has a limited maxi-
research in early light curves. mum exposure time, it should be
projects that Comets are notoriously variable in able to detect ISON at a time when
harness the eyes and intellects how they behave, especially com- it has crossed the solar system’s frost
of armies of volunteers, is going pared to predictions of their behav- line and warmed up enough to start
iour; comet Kohoutek (C/1969 O1) vaporizing frozen water. The meas-
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from strength to strength. The
results speak for themselves. In in 1969 is in the mind of many comet urements from Mars could help to
this issue, Karen Masters and observers, since it was widely talked refine estimates of the size of ISON’s
Chris Lintott report on an RAS up as a comet of the century but nucleus, which may in turn help to
Specialist Discussion Meeting proved to be less than spectacular. predict whether or not it will survive
on galaxy morphology, using the Comet ISON has been suggested as perihelion.
a naked-eye object for late Novem- Comet ISON was discovered on 21
work of Galaxy Zoo volunteers.
ber, but it may not survive its closest September 2012 by Vitali Nevski and
Galaxy Zoo members also chose
approach to the Sun on 28 November. Artyom Novichonok at the Interna-
the image we’ve used on the Comet ISON was observed by tional Scientific Optical Network
cover of this issue, for which I’m NASA’s Swift satellite in Janu- (ISON) telescope near Kislovodsk,
most grateful! ary 2013 and by the Hubble Space A Hubble Space Telescope Russia. It is believed to be inbound
More and more research Telescope in April, revealing some composite image of Comet ISON on its first passage from the distant
fields in astronomy have more activity consistent with release of taken in April 2013 with the Wide Oort Cloud, on a parabolic orbit that
data than ever before, thanks volatiles such as carbon dioxide. Field Camera 3. (NASA, ESA, Hubble will take it less than 2 million km
to large surveys and the careful The Spitzer Space Observatory cap- Heritage Team [STScI/AURA]) from the Sun at its closest point – a
curation of legacy information; tured a 3.6 µm image in July that sungrazing comet. Debate continues
disciplines in geophysics are also showed a plume of dust behind the et’s activity will increase as it passes over whether comet ISON will sur-
using the method, for example in comet as it approached the Sun, as Mars at the start of October, when vive perihelion. Observers will just
monitoring volcanoes. Whatever well as strong carbon dioxide emis- temperatures should increase enough have to wait and see.
the science, the challenge sion. Observers hope that the com- to start water-ice activity. NASA has http://www.isoncampaign.org
of handling large datasets is
not going to go away, so the
Zooniverse and its army of Are we martians, chemically speaking?
volunteers is making a significant
difference. Early in the history of the solar the annual Goldschmidt Confer- tified was that the early Earth was
system, Earth was a much less ence in Florence, set out two prob- covered with water, making it dif-
The benefits to researchers are
hospitable planet than Mars; the lems with the idea of life forming on ficult for elements such as boron or
clear, but what about that army
idea that life on Earth originated Earth. The first is the tar problem: molybdenum to build up into useful
of volunteers? Why do people on Mars has received a boost from if you add energy such as heat or concentrations.
choose to spend their free time chemical evidence that a form of light to organic molecules and leave Benner suggested this is further evi-
poring over scientific images? the element molybdenum that them alone, they don’t create life, but dence for life originating in the warm
The volunteers themselves say may have been essential for life rather turn into something more like wet conditions on the young Mars,
that they enjoy it, they like to to develop existed on Mars at the tar. Elements such as boron – found and reaching Earth via meteorites.
learn and that they get a lot of time – and not on Earth. in martian meteorites – and molybde- Climate change on Mars made it
satisfaction from contributing to Prof. Steven Benner from the Wes- num can stop tar forming and bring less hospitable to life, whereas Earth
research. They find things, too. theimer Institute for Science and about the reactions needed for life. became more habitable.
Hanny’s Voorwerp, a glowing Technology in Florida, speaking at The second problem Benner iden- http://bit.ly/14kQAPD
green object spotted by Galaxy
Zoo volunteer Hanny Van Arkel,
proved to be a new type of gas Looking ahead to the future of the Sun
cloud, for example.
In other words, there are quite A star very like the Sun – but 4 bil- Solar twins are rare; HIP 102152 is content suggests that stars somehow
a lot of people who don’t just lion years older – is giving astron- the oldest found. destroy lithium as they age.
enjoy finding out about research, omers a glimpse of how our star A key measurement for these stars A final twist in the story is that
will age. This “solar twin” also is the lithium content. Lithium HIP 102152 has an unusual chemi-
they want to be part of it, too.
suggests a link between stellar formed in the later stages of the cal composition pattern that is subtly
In the Zooniverse, they are part
age and lithium content. Big Bang, along with hydrogen and different to most other solar twins,
of it. This is not only a fabulous
An international team led by astron- helium. The Sun has very little lith- but similar to the Sun. They both
resource for research, but it is omers in Brazil has used ESO’s Very ium, just 1% of the primordial pro- show a deficiency of the elements
also a boost to our sciences. A Large Telescope to establish that star portion. Researchers have wondered that are abundant in meteorites and
lot of people out there support HIP 102152, 250 light-years away how typical the Sun is as a star, given on Earth. This is a strong hint that
astronomy and geophysics and 8.2 billion years old, is chemi- this unusually low lithium content. HIP 102152 may host terrestrial
strongly enough to do something cally very similar to the Sun. The HIP 102152 also has very low lith- rocky planets.
for it. That’s a lot of impact and team also found another star very ium levels, lower than the Sun, while This research was published in
long may it continue to expand. like the Sun but younger: 18 Scorpii, 18 Scorpii and other younger solar Astrophysical Journal Letters by
s.bowler@leeds.ac.uk which is 2.9 billion years old com- twins have higher proportions. The TalaWanda Monroe et al.
pared to our Sun’s 4.6 billion years. correlation between age and lithium http://www.eso.org/public/news/eso1337
5.4 A&G • October 2013 • Vol. 54
News
News in Brief
ALMA at 500GHz
Test observations with
the ALMA Band 8 receiver
developed by the National
Astronomical Observatory of
Japan have produced the first
high-resolution astronomical
images from a 500 GHz radio
interferometer. The images
of planetary nebula NGC 6302
delineate the distribution of
carbon atoms within the bipolar
nebula. The position of the
carbon matches the location of
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a gas and dust disc aorund the
central star. ALMA achieved a
resolution of 3.5 arcseconds in
this data and, when this receiver
is installed on all the antennas,
observers expect the resolution
to be 400 times better.
http://www.nao.ac.jp/en
ALMA takes aim at jets Dark skies spreading
The potential value of dark skies
for tourism and local prosperity
While still under construction, the Atacama Large Millimetre Array has produced this image of jets streaming is being increasingly widely
away from a young star, including one previously unknown jet. The ALMA data are superimposed on an optical recognized, and more and more
image of Herbig-Haro 46/47, a young star about 1400 light-years away in the southern sky constellation of Vela. regions are seeking official
Here the patterns of jets is almost a textbook image of molecular outflow from a young star, formed by the star’s designation. Chaco Culture
own winds. ALMA mapped the jets using carbon monoxide emission and used the Doppler shift to measure National Historical Park in New
surprisingly high gas velocities. The lobe to the upper left is moving towards Earth, that to the lower right away Mexico, US, now has Gold-tier
from us into the cloud of gas and dust that formed the star itself – the dark region on the optical image. The detail recognition as an International
in the ALMA image shows the interaction of this lobe with gas and dust, such as three clumps of matter associated Dark-Sky Association Dark Sky
by the researchers with episodic mass ejections every few hundred years. There is also evidence of a third jet, Park, while Alderney is hoping
perpendicular to the other two and here shown in green, possibly associated with a binary companion. These data to emulate Channel Islands
are published by Arce et al. in The Astrophysical Journal. (ESO/ALMA [ESO/NAOJ/NRAO]/H Arce/B Reipurth) neighbour Sark, which is a Dark
http://www.eso.org/public/news/eso1336 Sky Island. And Lochinver, in the
far northwest of Scotland, has
been granted Dark Sky status
for Leitir Easaidh All Abilities
Heavy weather: stars with clouds of lead Path at Little Assynt Estate,
by the UK Dark Sky Discovery
Researchers from Armagh Obser- of the Sun, and faint blue subdwarfs, become detectable from Earth. Project. Leitir Easaidh has been
vatory in Northern Ireland have stars one-fifth the size but seven The team suggests that the new noted as an area where the
found two unusual stars with times hotter and 70 times brighter discoveries are rare examples of MiIky Way can easily be seen,
extremely high concentrations of than the Sun. these layers coming into view. They and it is also a good place to
lead in their atmospheres. A few red giants lose their thick estimate that the lead layer could be view the aurora.
One of the stars also has high levels hydrogen skin and shrink to become about 100 km thick and weigh some http://www.darkskydiscovery.org.uk
of yttrium and zirconium. The unu- hot subdwarfs, or nearly-naked 100 billion tonnes. http://www.darksky.org
sual chemistry suggests a new group helium stars, which develop layers of The research is published in
of “heavy metal subdwarfs”, which different elements. A layer of heavy Monthly Notices of the Royal Astro- 2014 Kavli Prize
may be a link between bright red metal at just the right height and con- nomical Society. The Norwegian Academy of
giants, stars 30 or 40 times the size centration can then form clouds that http://bit.ly/1fujW2O Science and Letters is seeking
nominations for the 2014 Kavli
Prize in Astrophysics. The prizes,
Lazarus comets lurk in the asteroid belt awarded by an international
committee, recognize “seminal
Comets that orbit within the main belt orbiting like asteroids but behav- ity in the asteroid belt than collisions. advances in astrophysics” and
belt of asteroids as if completely ing like rocky comets, sublimating Ferrin and his team call this group consist of a scroll, a medal and
inactive may be able to come back water, for example. Ferrin described of comets Asteroidal Belt Comets a cash award of one million
to life after millions of years, a this region as a graveyard for com- and suggest that they are relics of a dollars. Kavli laureates include
team of astronomers from the ets, but noted that perturbations of much greater population of comets Donald Lynden-Bell and
University of Anitoquia, Medellin, their orbit could result in them com- within the asteroid belt. Millions Maarten Schmidt, for their work
Colombia, have discovered. ing back to life, like Lazarus. Just a of years ago, therefore, there would on quasars; teams working
Over the past ten years, 12 active few percent increase in the energy have been much more cometary on telescope design and the
comets have been discovered in they receive from the Sun is enough activity in this region of the solar Kuiper Belt have also been
the asteroid main belt. Anitoquia to revive them. This could happen system. This work is published in honoured. Nominations close on
astronomer Prof. Ignacio Ferrin and to comets that had spent millions of the Monthly Notices of the Royal 1 December 2013.
his team wondered why. They found years dormant and may be a more Astronomical Society. http://www.kavliprize.no
a population of objects in the main significant reason for cometary activ- http://bit.ly/17EaJ9e
A&G • October 2013 • Vol. 54 5.5
News
News in Brief Astronomy for
Expect more Trojans peace in India
Models of the distribution of The Telegraph, India newspaper
asteroids in the outer reaches reports that astronomers were
of the solar system suggest able to help out the Indian Army
that transient objects trapped in and avoid an international inci-
orbit with the giant planets are dent in the sensitive border region
relatively common. Researchers of Ladakh. For six months, army
suggest that 3% of scattered observers noted with concern
objects between Jupiter and the presence of objects in the sky,
Uranus share an orbit with thought to be drones crossing the
Uranus or Neptune. They have border from China; they were in
also discovered the first uranian fact the planets Jupiter and Venus.
Trojan – QF99 – which has been Eastern Ladakh is a sensitive region
captured within the past few and accusations of cross-border
Downloaded from https://academic.oup.com/astrogeo/article/54/5/ASTROG/250317 by guest on 31 December 2020
hundred thousand years and is transgressions are taken seriously.
likely to escape Uranus’s gravity Army observers are posted along the
in about a million years. These border at high altitudes; in this case,
temporary Trojans offer a means the observer was meticulous. “The
of studying the migration of small first object, viewed from a location
bodies in the solar system. The about 4715 m above sea level near
results are published in Science. Thakung, appeared in the horizon
Perseid meteors prove
http://www.science.ubc.ca/node/724 at about 6 p.m. and remained visible
until about 5 a.m. The second object
Leaky magnetar appeared at 4 a.m. and faded away
The first measurement of the
local surface magnetic field on a
neutron star suggests that it has
popular at Gemini South at 11 a.m.” reported the Telegraph.
A regular army observer, Shemin-
derpal Singh, noted that the objects
an internal field as strong as any Looking out for the Perseid meteor shower in August is a popular summer seemed to be the brightest in the sky,
in the universe, leaking outward activity, but one group of astronomers is particularly pleased to see them: and seemed to move with respect to
in a small region of the surface. those using the Gemini Observatory’s adaptive optics (AO) system. the stars. He also noticed that one
Magnetars are tiny stars – around Gemini’s AO system uses a laser to excite sodium atoms at about 90 km of the objects appeared four minutes
20km across – with strong altitude, producing guide stars with which to map the atmospheric distortion later each day.
magnetic fields and unusual affecting images. The Perseid meteors, among others, supply that sodium. The army asked the Indian Insti-
X-ray outbursts and giant flares. “It’s a form of natural pollution,” says Chad Trujillo of Gemini Observatory tute of Astrophysics, Bangalore,
Data from ESA’s XMM-Newton South in Chile. “We can make it glow by using a sodium laser and produce for advice. The evening object was
X-ray space telescope showed a temporary, artificial stars.” Gemini South is now using a constellation of Jupiter, the morning one Venus – not
systematic variation in emission five guide stars, produced by splitting the 14W, 589nm laser to get better aliens and certainly not spies.
from SGR 0418+5729, a magnetar resolution over a wider area. (Gemini Observatory/AURA) With thanks to David Harper.
with a relatively benign dipole http://www.gemini.edu/node/12050 http://bit.ly/17zi9qA
field overall. The X-ray signal
dropped regularly, at the same
point in the star’s 9-second
rotation period. This could arise
Einstein@Home discovers 24 new pulsars
from absorption of the radiation Distributed computing using spare search for new radio pulsars is very
by part of the surface – possibly computer time donated by volun- computer-intensive. To determine
a patch of protons a few hundred teers has resulted in the discovery the a priori unknown characteris-
metres across – where the strong of 24 new pulsars in data from the tics of the pulsar, e.g. its distance or
inner magnetic field emerges. CSIRO Parkes radio telescope in its rotation period, we have to very
The data are published in Nature Australia. finely comb through wide parameter
by Tiengo et al. Einstein@Home involves 50 000 vol- ranges,” says Knispel.
http://sci.esa.int/xmm-newton/52772 unteers from around the world who Raw computing power was not the
“donate” idle compute cycles on their only important factor; new post-pro-
IMAX Hidden Universe 200 000 home and office machines. cessing methods were just as crucial,
A 3D film that explores The result is that the scientist lead- for example in removing pulsar-like,
the European Southern ing the project, Benjamin Knispel, man-made interference signals.
Observatory’s Very Large researcher at the Max Planck Insti- Out of the 24 pulsars, six are in
Telescope and the Atacama tute for Gravitational Physics (Albert binary systems and one has an unu-
Large Millimetre Array is now Einstein Institute/AEI) in Hannover, sually long orbital period of about
on release at IMAX cinemas has a sustained computing power 940 days – the fourth longest known.
worldwide. The film shows of around 860 teraflops. Einstein@ In the future, it could be used as a
state-of-the-art telescopes in Home volunteers get a screensaver test bed for Einstein’s general theory
high-resolution time-lapse, that displays information about the of relativity.
mesmerizing 3D versions of processing on the volunteer’s com- While these exotic pulsars stand
celestial structures, and a 3D puter, the sky position currently out, discovery of more “normal” pul-
simulation of the evolution of being analysed. sars is also important. This survey is
the universe. Viewers will also Knispel and his colleagues were Volunteers can now sign up for often used as a reference for model-
explore the skies and the surface working on data from the Parkes Einstein@Home using Android ling the distribution of pulsars in our
of Mars and take a close look at Multi-beam Pulsar Survey, conducted smartphones and tablets as well galaxy; these formerly hidden pul-
the Sun. from 1997 to 2001, with the 64 m as home computers. (Max Planck sars will improve these simulations.
http://www.hiddenuniversemovie.com antenna of CSIRO’s Parkes radio tel- Institute for Gravitational Physics/B http://www.aei.mpg.de
escope in southeast Australia. “The Knispel, NASA) http://einstein.phys.uwm.edu
5.6 A&G • October 2013 • Vol. 54
News
Citizen science targets volcanoes Home from
Citizen science projects in which
home for RAS
members of the public scan
images and pick out items of inter-
astrochemists
est have become a valuable tool in RAS Fellows can now join the
astronomy and planetary sciences. Astrochemistry Subdivision of
Now Earth scientists are harness- the American Chemical Society as
ing the power of the people in a Affiliate Members.
project to monitor the volcano on Astrochemistry presents both an
Montserrat. interdisciplinary and a multidiscipli-
Projects such as Galaxy Zoo and nary field with ties to the traditional
Moon Zoo have proved their worth disciplines chemistry, planetary sci-
in research, with people not only ence, chemical biology, physics and
identifying likely landing sites on astronomy. The Astrochemistry Sub-
the Moon, but also discovering new division provides an interdisciplinary
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objects in space. Now research stu- home for individuals interested in
dent Jonathan Stone of the Univer- astrochemical research in the form
sity of East Anglia has established a of experiments, theory, observations,
community-based monitoring system Locals are monitoring the Soufrière Hills volcano on Montserrat. (Godot13) space missions and modelling.
on the Caribbean island of Montser- Here chemistry, defined as the
rat, scene of a devastating volcanic (UNISDR) for greater community want a citizen science project to last change of matter, is vital in unravel-
eruption in 1995. involvement in risk reduction, and more than a month or two, you need ling the chemical and astrobiological
Local residents have been using its methods have potential for appli- to make sure that data collection is evolution of matter on the micro-
kites to take aerial photographs of cation elsewhere. a fun and useful thing to do. Who scopic (elementary chemical reac-
the island, as well as using surveys Stone feels that citizen science doesn’t want to fly a kite or a quad- tions) and macroscopic (planets,
with GPS data to monitor how the projects that fly kites and remote- copter with a camera attached to it?” moons, interstellar medium) levels.
landscape is changing as a result of controlled quadcopters (a helicop- This research was presented at a The composition of each macro-
volcanic mudflows. The project was ter propelled by four rotors) to take joint Royal Geographical Society scopic environment reflects the mat-
developed in response to a call made aerial photographs and video of vol- and Institute of British Geographers ter from which it was formed and
by the United Nations International canic processes could reduce hazard conference in London. the chemical processes that have
Strategy for Disaster Reduction risk worldwide. He explains: “If you http://bit.ly/15y8m1e changed the chemical nature since
its origin. For this reason, a detailed
investigation of the processes alter-
Chandra marathon uncovers black hole habits ing the chemical composition of
the pristine environment is critical
The giant black hole at the centre 2012 and researchers have produced needs to lose momentum and heat, for understanding both its contem-
of the Milky Way galaxy is a sur- unusually detailed and sensitive carried away by the ejected material. porary makeup and its origin and
prisingly faint X-ray source. The X-ray images and energy signatures “Most of the gas must be thrown chemistry. Astrochemistry requires
longest set of observations per- of the super-heated gas swirling out so that a small amount can reach concerted interdisciplinary relation-
formed with the Chandra X-ray around Sgr A*. The data did not sup- the black hole,” said Feng Yuan of ship between chemists, physicists,
Observatory now shows why: port theoretical models in which the Shanghai Astronomical Observa- astronomers, chemical biologists and
despite gas accumulating around X-rays are emitted from a concentra- tory in China, the study’s co-author. planetary scientists.
the black hole, 99% of it is ejected tion of smaller stars around the black “Contrary to what some people The American Chemistry Society
before it reaches the event horizon hole. Instead the gas near the black think, black holes do not devour welcomes RAS Fellows in this field
and so does not heat up and glow hole is likely to originate from winds everything that’s pulled towards and encourages interested astrochem-
in X-rays. produced by a disc-shaped distribu- them. Sgr A* is apparently finding ists to complete a division application
Chandra’s five weeks’ worth of data tion of young massive stars. The gas much of its food hard to swallow.” form from the membership site here:
on Sagittarius A* were collected in that does reach the event horizon http://arxiv.org/abs/1307.5845 http://bit.ly/1ae2Byf
More water found on the Moon
Researchers using data from mapper orbiting on the Indian Space
NASA’s Moon Mineralogy Mapper Research Organisation’s Chan-
have established that water found drayaan-1 spacecraft, confirms the
on the surface of the Moon origi- existence of internal water.
nated in its interior. “Understanding this internal com-
Although the Moon had long been position helps us address questions
considered a dry body, surface water about how the Moon formed, and
has recently been found, arising from how magmatic processes changed
solar wind interactions with the reg- as it cooled,” said Rachel Klima,
olith. This discovery, in rocks in the a planetary geologist at the Johns
crater Bullialdus, is of hydroxl ions Hopkins University Applied Physics
in water bound to minerals erupted Laboratory. “Now we need to look
from the Moon’s interior. The rock- elsewhere on the Moon and try to
type – norite – is unusual and the test our findings. In some cases this
crater lies in a region otherwise low will involve accounting for the sur-
in surface water. face water that is likely produced by
Water had been found in Apollo interactions with the solar wind, so it
samples of Moon rocks, but had will require integration of data from
been considered contamination form many orbital missions.” The lunar impact crater Bullialdus contains significantly more hydroxyl
Earth. This discovery, from the M3 http://bit.ly/15mcHWa compared to its surroundings. (NASA/GSFC/Arizona State University)
A&G • October 2013 • Vol. 54 5.7
News • Mission Update
Space Shorts
SpaceX in Europe
SpaceX, the commercial rocket
developer, has won its first
contract in Europe, to launch
radar reconnaissance satellites
Mission update
for the German Ministry of
Defence’s SARah constellation.
WISE wakes up
The satellites, provided by OHB NASA’s asteroid initiative, to achieve
System AG and Astrium GmbH, President Obama’s goal of sending
will be launched by Falcon 9 humans to an asteroid by 2025, has
rockets in 2018 and 2019. OHB resulted in a new lease of life for a
will build two passive-antenna venerable spacecraft. The Wide-field
synthetic aperture radar (SAR) Infrared Survey Explorer (WISE) is
satellites, and Astrium GmbH to be reactivated in September in 1: Annular eclipse of the Sun by Phobos, as seen by Curiosity from the
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will build a larger, phased-array- order to find and characterize near- martian surface. The images are three seconds apart. (NASA/JPL-
antenna satellite under contract Earth objects (NEOs) within 45 mil- Caltech/Malin Space Science Systems/Texas A&M Univ.)
for OHB. The three-satellite
A year on Mars
lion km of Earth’s orbit around the
constellation will replace the Sun. NASA anticipates that WISE
current OHB-built five-satellite will discover about 150 previously
SAR-Lupe constellation. unknown NEOs and characterize the NASA’s Curiosity rover has Mastcam, was part of the team
http://www.spacex.com size, albedo and thermal properties now spent more than a year on using data from the moons’ orbits
of about 2000 others, using its 40 cm Mars and has already found to better understand martian
Japan’s new rockets telescope and infrared cameras. evidence of flowing surface water solid tides and the internal
The Japanese Space Agency The WISE mission, from January and favourable conditions for structure of the planet.
(JAXA) has successfully 2010 to February 2011, was to scan microbial life in the early history Meanwhile, the Mars Science
launched H-IIB Launch the entire celestial sky in infrared of the planet. In addition, the Laboratory mission continues
Vehicle No. 4 with cargo for the light. It captured more than 2.7 mil- mast cameras (Mastcam) on the with the rover starting to test its
International Space Station, lion images in multiple infrared rover recorded one of Mars’s autonomous navigation system on
onboard. It lifted off from the wavelengths and catalogued more moons passing in front of the unknown ground. Curiosity uses
Tanegashima Space Center than 560 million objects in space, other on 1 August this year. stereo images of the ground ahead
on 4 August. However, the ranging from galaxies to asteroids Phobos, the larger moon, passed to plan a route, a method adapted
launch of Epsilon-1, a rocket and comets, including the most in front of Deimos, from the point from the Mars Exploration Rover
intended to provide frequent accurate survey to date of NEOs, of view of the rover’s cameras, the Opportunity. The rover had used
launches, was stopped by an NEOWISE. Discoveries included 21 first time this has been recorded. the navigation system before, but
automatic alarm 19 seconds comets, more than 34 000 asteroids Mars Science Laboratory on terrain identified as safe from
before lift-off. Epsilon-1 was in the main belt between Mars and researchers compiled a series of Earth; this was the first drive into
intended to carry Japan’s Jupiter, and 135 NEOs. still images into a video, and will the unknown. Around 10 m of the
SPRINT-A (Spectroscopic Planet “The WISE mission achieved its be using the event to study the total of 43 m driven – a section
Observatory for Recognition mission’s goals and, as NEOWISE, orbits of the moons. hidden by a dip in the ground
of Interaction of Atmosphere), extended the science even further in Later in the month, Curiosity – was navigated autonomously.
a space observatory intended its survey of asteroids. NASA is now also took images of Phobos in The rover is now on its way to
for research on planetary extending that record of success, an annular eclipse of the Sun. Mt Sharp, where layered rocks
atmospheres. which will enhance our ability to Mark Lemmon of Texas A&M indicate a likely place to explore
http://www.jaxa.jp find potentially hazardous asteroids, University, College Station, a the ancient environment of Mars.
and support the new asteroid initia- co-investigator for the use of http://mars.nasa.gov/msl
Comet looks lively tive,” said John Grunsfeld, NASA’s
Comet Churyumov- associate administrator for science
Gerasimenko, the target of in Washington. “Reactivating WISE working reaction wheel systems can- one of the shortest orbital periods
ESA’s comet-chasing mission is an excellent example of how we are not point precisely enough to detect ever detected: 8.5 hours. The planet
Rosetta, is likely to become leveraging existing capabilities across further exoplanets. The mission is extremely close to its star, with an
active earlier than anticipated, the agency to achieve our goal.” team announced a call for proposals orbital radius only about three times
according to models of its http://1.usa.gov/17qPGTY for a two-wheel Kepler mission on 2 the radius of the star – about 40 times
behaviour based on data August this year. closer to its star than Mercury is to
from its previous three orbits.
According to Colin Snodgrass New directions Kepler was launched to investigate
the abundance of planets around
the Sun. As a result, its surface tem-
peratures could reach 3000 K and its
of the Max Plank Institute for
Solar System Research, lead for Kepler other stars and its four years of data
has so far produced 135 confirmed
surface is probably entirely molten,
a massive, roiling ocean of lava. The
author of the study, “Churyumov- NASA’s Kepler Space Telescope team discoveries and 3500 candidates. MIT team was able to detect light
Gerasimenko could be active has stopped trying to restore the More are expected, including Earth- emitted by the planet – a first for such
by March of next year”. Rosetta, spacecraft to full working order, and like planets orbiting in the habitable a small exoplanet – which may in
currently in deep-space is instead investigating what investi- zones of their stars. future provide detailed information
hibernation, will be reactivated gations the spacecraft can carry out http://1.usa.gov/194B6m9 about the planet’s surface composi-
in January 2014, approach the in its current state. tion and reflective properties.
comet in spring, land on it in
the autumn and stay with the
Two of the original four sets of
reaction wheels and thrusters used Close exoplanet Kepler 78b is so close to its star that
scientists hope to measure its gravi-
comet as it approaches the
Sun. The results of the study
to orient the Kepler spacecraft have
stopped working, the first in July is hot stuff tational influence on the star. Such
information may be used to meas-
are published in Astronomy and 2012, the second in May of this year. An Earth-sized exoplanet discovered ure the planet’s mass, which could
Astrophysics. The spacecraft is now in a stable con- by the Kepler mission – Kepler 78b – make Kepler 78b the first Earth-sized
http://sci.esa.int/rosetta figuration and able to use thrusters has been characterized by research- planet outside our own solar system
to maintain this, but without three ers from MIT who found that it has whose mass is known. The paper was
5.8 A&G • October 2013 • Vol. 54
News • Mission Update
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Spitzer at 10
The infrared observatory Spitzer has been at work for 10 years, revealing the cool dusty regions where stars and planets form, as well as shedding
light on planets, exoplanets, stars and galaxies. Spitzer data have brought a better understanding of the Milky Way’s spiral arm structure, led to the
discovery of Saturn’s largest and faintest ring, and the observatory was the first to detect light from an exoplanet. Spitzer has enabled astronomers to
investigate the composition, dynamics and atmospheres of exoplanets. This image shows the Carina Nebula, a region where dust and gas are shaped
by winds and radiation from the massive star Eta Carinae (100 times the mass of the Sun). Infrared wavelength radiation from the star destroys dust,
leaving cavities within the nebula surrounded by higher density “spikes”. This Spitzer image, reprocessed as part of the Galactic Legacy Infrared Mid-
Plane Survey Extraordinaire (GLIMPSE) project, uses Spitzer’s infrared array camera, with emission from wavelengths of 3.6 µm shown in blue, 4.5 µm
in green and 8.0 µm in red. In the composite image, the dust appears red and the hotter gas, green. Spitzer was originally called the Space Infrared
Telescope Facility, and was renamed after its launch in honour of the late astronomer Lyman Spitzer. It is one of NASA’s Great Observatories, together
with the Hubble Space Telescope, the Chandra X-ray Observatory and the now-defunct Compton Gamma Ray Observatory. Spitzer used up its coolant for
longer-wavelength observations in 2009, and is now continuing to work in the “warm mission phase”. (NASA/JPL-Caltech)
http://spitzer.caltech.edu
published by Josh Winn of MIT in the orientation of the magnetic field NASA’s Voyager project scientist, beneath the visible part of an iceberg.
The Astrophysical Journal. it is encountering. But a different Ed Stone of the California Insti- On Earth, mountain ranges have
http://bit.ly/1fnIN8x model, published in The Astrophysi- tute of Technology in Pasadena. deep low-density roots, but the roots
cal Journal in September, suggests “We will continue to look for any on Titan are overwhelming the extra
Where exactly that Voyager crossed the heliopause
in 2012. This model uses analysis of
further developments over the com-
ing months and years as Voyager
mass of the slight surface bulges.
The researchers working on the
is Voyager? reconnection between the stellar and
interstellar fields on a fine scale to
explores an uncharted frontier.”
http://voyager.jpl.nasa.gov
data, Douglas Hemingway and
Francis Nimmo of the University of
The location of the Voyager 1 space- suggest that the heliopause is porous California, Santa Cruz, USA, liken
craft – inside or outside the solar
system – is a matter of debate, compli-
and layered, with a complex local
structure. The team, led by M Swis- Cassini tracks the effect to that of a giant beach
ball beneath the outer ice shell; the
cated by uncertainty about the nature
of the boundary that the spacecraft is
dak of the University of Maryland,
USA, suggests that such a structure Titan’s shell crust of Titan must be strong enough
to hold it down. They estimate that
in the process of traversing. would give rise to the varying densi- Researchers examining Saturn’s larg- Titan should have a rigid ice shell
Voyager is in the region of space ties of particles from the heliosphere est moon Titan have found evidence at least 40 km thick, if low-density
where the Sun’s magnetic field, and the interstellar medium detected that it has a strong rigid ice shell, roots are the origin of the correla-
defining the heliosphere, meets the by Voyager. on top of a subsurface ocean. The tion between topographic highs and
interstellar field. Precisely where The Voyager mission was launched analysis of gravity and topography gravity lows.
the spacecraft is with respect to this to explore the solar system and is data from NASA’s Cassini showed If this is the case, then ice volcanoes
boundary – the heliopause – depends continuing that exploration at its that, where Titan’s surface bulges, would be difficult to form on Titan,
on the models used to understand current distance of 18 billion km the gravity signal decreases. This although they have been proposed to
how magnetic fields interact. NASA from the Sun. “The Voyager 1 space- correlation suggests that there is explain some surface features. The
researchers consider that Voyager is craft is exploring a region no space- more low-density material beneath research was published in Nature.
still within the heliosphere based on craft has ever been to before,” said topographic highs, like the keel of ice http://www.nature.com
A&G • October 2013 • Vol. 54 5.9
Raafat et al.: Mining in space
Asteroids and planets are
potentially valuable mineral
resources, but finding and
exploiting them will be a
challenge. Kian Raafat, Jordan
Burnett, Thomas Chapman and
Charles S Cockell ask: what’s
different about mining off Earth?
A
steroids and other planetary bodies
including the Moon offer mining and
resource potential, with supplies of
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minerals including platinum group elements
and metals (Busch 2004, Sonter 1997) (figure 1).
Effective mining requires the extraction of these
elements and compounds from rocks in solu-
tion, and therefore we need an understanding
of how particles behave in fluids in altered grav-
ity environments. What factors might control
our ability to mix rocks with fluids in space and
thereby efficiently mine in space? The addition of
a biological component (in “biomining” opera-
tions) adds an additional complexity, generating
the problem of understanding particle–liquid–
microbe interactions in altered gravity regimens.
Microgravity affects many simple processes in
surprising and useful ways. Much of the initial
research and experimentation was pioneered by
astronauts on Skylab and Apollo 14 missions,
with subsequent missions by NASA and ESA
(Winter and Jones 1996, Ceglia and Sentse
The physics of m
2007). These provide ample documentation
to begin to explore the topic with some direct
physical experimentation. Quite apart from
mining, understanding the interaction of fluids
and particles (including microbes) in space has
applications to understanding fluid distribution
in rocket propulsion, crystal growth in space
and the behaviour and manufacture of advanced (Naumann and Herring 1980). The presence of solutions, this means that a dense solute does
materials such as pure alloys. particles in the liquid will increase its density not sink and collect at the bottom of a receptacle
Motivated by our role as the scientific coordi- at distinct points, which can cause microflows and a lighter substance does not rise. Mathe-
nators of an ESA ELIPS project called BioRock, because it will create concentration gradients. matical modelling in this area is relatively sim-
which seeks to use the International Space Sta- However, these will quickly dissipate and the ple and we can say that mixtures of materials
tion to investigate the behaviour of microbes in mixture will find equilibrium again. Surface will remain stable in the liquid state and when
contact with particles in altered gravity regi- tension effects in microgravity will impact min- freezing (Naumann and Herring 1980). In prac-
mens (see “BioRock – a mining experiment in ing efficiency because liquids inside a mining tice, measuring buoyancy has proved a chal-
space” p5.12), we provide a brief summary of reactor in a low-gravity environment, such as on lenge. Measurements have been taken on board
the factors underlying the physical principles the surface of an asteroid, will form balls. These various existing space missions, but results have
that govern the behaviour of particles in liquids are likely to reduce the efficiency of elemental been inconsistent because of the instability of
in a microgravity environment, with a focus on extraction from rocks because the individual the value of g when in orbit around the Earth
extraterrestrial mining. balls of fluid may reach near-saturation for (Shephard and Best 2010). Understanding the
some elements as leaching occurs. These effects buoyancy of particles under different gravity
Surface tension suggest that finding efficient mixing methods environments is essential for understanding how
In space, gravity is no longer the dominant fac- to keep liquids and particles perturbed will be particles would behave in mining reactors.
tor in shaping liquids. As a result, a liquid takes essential for mining in space.
the shape that minimizes surface area without Convection
having to contest with gravity – usually a sphere. Buoyancy There are various ways in which particles can
The surface tension of liquids in microgravity Buoyancy is the net upward force that a travel through a liquid, generally considered
can be found by simply perturbing suspended fluid exerts on an object and, with no net as types of convection. On Earth, convection
droplets of the required mixture and measur- upward force in microgravity, particles can is controlled by variables such as density gra-
ing the natural frequency of their oscillations be suspended in liquid almost indefinitely. In dients, buoyancy forces and temperature. In
5.10 A&G • October 2013 • Vol. 54Raafat et al.: Mining in space
1: Lunar stations would allow the establishment
of mining facilities on the surface of the Moon. In
this artist’s concept, a mining facility harvests
oxygen from the resource-rich volcanic soil
of the eastern Mare Serenitatis. The high iron,
aluminium, magnesium and titanium content
could be used as raw material for a lunar metals
production plant. (P Rawlings, SAIC, NASA)
division of these phases is less definitive.
A free surface is the surface that separates a
solid or liquid from surrounding gas. In micro-
gravity, as previously mentioned, liquid takes a
form with the lowest surface area – a sphere – to
minimize its free surface. On Earth, the free
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surface boundary is responsible for flow that is
induced by temperature and composition varia-
tions, thus in microgravity, where free surface is
minimized, there is also a reduction in internal
fluid motion. To improve mixing, sites near a
massive planetary body could provide better
flow rates because of an increase in gravity dif-
ferentials, but this may be, at times, an imprac-
tical solution. Using smaller molecules and less
viscous solutions in practical applications could
also allow for speedier mixing.
Several methods of artificially stimulating
mixtures have been developed by NASA with
the purpose of rehydrating medical supplies
(such as intravenous fluids) on board a space-
craft. The most promising and novel methods
developed so far include the non-intrusive
method of vibrating the surface of the recepta-
cle to induce diffusion, using acoustic streaming
mining in space
to introduce density gradients in the liquid, or
inserting a magnetic rotating shaft into an open-
ing and into the liquid to provide large internal
speeds (Niederhaus and Miller 2008). These
methods have various practical issues that must
be solved, but they could all be applied to stimu-
lating the processes involved in asteroid mining.
microgravity, there are two convection mecha- It is interesting to note the role that a small
nisms that are capable of creating a current in celestial body’s rotation might have on forced Boundaries
the liquid in which particulates might travel: convection, raising the possibility that an aster- It is also important to consider how liquids
the Marangoni effect and forced convection. oid’s centripetal force could be used to drive respond to solid surfaces, because wetting dif-
The Marangoni effect, most commonly dem- circulation of particulates in mining reactors. fers in microgravity. In microgravity, the surface
onstrated with the “tears of wine” experiment tension force is dominant and liquids may main-
(Matsumoto et al. 2010), depends on the ten- Mixing tain contact with solid surfaces. The presence
dency of liquids to travel from areas of low The mixing of substances in microgravity is a of electrostatic forces can affect the result of
surface tension to higher surface tension. This slow natural process. So slow, in fact, that when wetting. The contact angle (the angle where a
mechanism still works in microgravity. This tea granules were placed in a water tank on a liquid/vapor interface meets a solid surface) and
method of convection could be used in min- Skylab mission, it took nearly 52 hours for them the contact line (the interface itself) are believed
ing reactors on asteroids to get masses moving to diffuse only 1.96 cm (Skylab SD15-TV115 to be the main factors that determine the inter-
through a liquid, simply by creating a surface experiment). Given enough time, these granules face shape and stability of the resulting system
tension differential. would distribute themselves evenly in a liquid, (Chen et al. 2009, Brutin et al. 2009).
Another type of convection that will offer value but the time proves to be a significant constraint. The behaviour of insoluble particles when they
in microgravity is forced convection. This is seen The problem is threefold. First, as mentioned encounter multistate systems must be described
in everyday life in simple devices such as bellows, above, a decrease in buoyancy reduces the move- in order to predict their reactions. A change
which create a pressure difference, forcing the ment of particles. Second, low gravity inhibits of state in water, for example, could result in
circulation of air in a contained environment. granule motion and flow velocities. Third, in boundaries where both solid and liquid water is
In microgravity, creating a pressure gradient can microgravity, mixtures separate into distinct present. Liquids at a boundary behave differently
be an effective way of circulating heat and mass phases less readily. On Earth, buoyancy causes to a volume of bulk liquid. In mining, it is pos-
through a system. This was used on NASA’s separation: gas sits on the top of a container and sible that particles will be engulfed by the liquid,
space shuttles as a method for heating food. the liquid on the bottom. In microgravity, the and then encapsulated by it. It is also possible
A&G • October 2013 • Vol. 54 5.11You can also read
