New Eyes on the Sun

257 Pages·2012·8.548 MB·English

by  Wilkinson, John

Astronomers’ Universe
For other titlespublished inthis series, goto
http://www.springer.com/series/6960
.
John Wilkinson
New Eyes on the Sun
A Guide to Satellite Images and Amateur
Observation
Dr.JohnWilkinson
4RossDrive
Castlemaine,Victoria,3450
Australia
[email protected]
ISSN1614-659X
ISBN978-3-642-22838-4 e-ISBN978-3-642-22839-1
DOI10.1007/978-3-642-22839-1
SpringerHeidelbergDordrechtLondonNewYork
LibraryofCongressControlNumber:2011939837
# Springer-VerlagBerlinHeidelberg2012
Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialis
concerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,broadcasting,
reproductiononmicrofilmorinanyotherway,andstorageindatabanks.Duplicationofthispublication
orpartsthereofispermittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember9,
1965,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer.Violations
areliabletoprosecutionundertheGermanCopyrightLaw.
Theuseofgeneraldescriptivenames,registerednames,trademarks,etc.inthispublicationdoesnot
imply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevantprotective
lawsandregulationsandthereforefreeforgeneraluse.
Coverfigure:TheSolarProbePlusspacecraftwithitssolarpanelsfoldedintotheshadowsofits
approachtotheSun.Credit:NASA/JHU/APL.
Printedonacid-freepaper
SpringerispartofSpringerScience+BusinessMedia(www.springer.com)
Preface
TheSunistheonlystarintheuniversethatiscloseenoughforus
to see its features in intricate detail. Astronomers have observed
the Sun over many centuries from Earth but in recent decades
they have gained a new understanding via scientific instruments
insatellites(spaceprobes).Theremarkabledynamicalphenomena
occurring on the Sun, such as eruptions of matter in the form
of prominences, filaments, spicules, coronaloutbursts, and gigan-
tic flares make the study of the Sun extremely fascinating and
interesting.
Activity on the Sun is the most energetic in our Solar System.
Without the Sun’s energy in the form of heat and light, life on
Earth could not exist. The Sun also affects our weather, climate
and communication systems, and an understanding of it is essen-
tial to daily life.
In the past, observing the Sun has been left to academics with
specialised instruments, since solar observation has been unsafe
because of the risk of eye damage. It is now possible for amateur
astronomers to safely observe the various solar phenomena using
specialhydrogen-alphatelescopesthatarenottooexpensive.Ama-
teurscannowmakeapositivecontributiontosciencebymonitor-
ing the Sun as professionals do.
Most of the new information about the Sun has come from
recentsatellitesthatobservetheSunonadailybasisusingvisible,
x-ray and ultraviolet wavelengths of electromagnetic radiation.
Amateurs can also access the solar images taken by satellites via
theinternetandsmartphones.Thisbookhelpsreadersinterpretand
understand what these images are showing about the Sun. Readers
will enjoy comparing their own solar telescope observations with
v
vi Preface
those produced by space probes such as SDO, SOHO, Hinode
and STEREO.
The main purpose of this book is to present some of the
fascinatingsolarphenomena,intheirfullglorytoreadersthrough
avarietyofillustrations,photographsandeasytounderstandtext.
Solar astronomy is becoming very popular among amateur
astronomers as well as academics. Amateurs can use special tele-
scopes to observe the Sun every day. Many surface features show
changes in appearance every hour – this is different to night time
observing where the appearance of objects remains fairly static
night after night. This book also provides the latest space probe
information for people interested in studying the Sun and more
importantly, it bridges the gap between advanced astrophysics of
the Sun and elementary knowledge aboutthe Sun.
Inrecentyearsanewterm,spaceweather,hascomeintovogue
to describe the effect the Sun’s radiation has on Earth and the
environment of space near Earth. The study of space weather is
criticaltooursurvivalandtoanunderstandingofourenvironment.
Linked to space weather is the effect of the Sun on Earth’s
climate. Many scientists think that we are undergoing climate
change and believe that the Sun may be a cause of this change.
The final chapter of this book looks at the Sun as a star. There
are many different types of stars each with particular characteris-
tics. Stars also go through a life cycle whereby they grow, change
anddie.Readerswillenjoylearningabouttheevolutionandfateof
the Sun as a star.
Hopefully you will find enjoyment in this book and improve
your understanding of the Sun and enjoy the growing hobby of
Solar Astronomy.
Dr John Wilkinson
Acknowledgments
Theauthorandpublisheraregratefultothefollowingfortheuseof
photographs in this publication: National Aeronautics and Space
Administration (NASA), European Space Agency (ESA), Goddard
Space Flight centre (GSFC), Johnson Space Centre (JSC), Japan
Aerospace Exploration Agency (JAXA), the Royal Swedish Acade-
my of Science and LMSAL. Many of the photographs have been
taken from recent space probes used to study the Sun up close,
suchasSOHO,STEREO,TRACEandSDO.Creditforeachphoto-
graphisprovidedwiththecaptions.Wherecreditisnotgiven,the
photo is the author’s.
TheauthorwouldliketoacknowledgetheassistanceofStephen
Ramsden (USA) for his advice and help with some of the photo-
graphs of solar observing equipment.
Whileeverycarehasbeentakentotraceandacknowledgecopy-
right,theauthorapologisesinadvanceforanyaccidentalinfringe-
ment where copyright has proven untraceable. He will be pleased
tocometoasuitablearrangementwiththerightfulownerineach
case.
Note: Thewebsitesusedinthisbookwerecorrectatthetimeof
publication.
vii
.
Contents
1 Warming to the Sun ......................................... 1
The Solar System ........................................ 1
The Sun .................................................. 6
Source of Energy and Luminosity ...................... 9
Interior of the Sun ...................................... 10
The Sun’s Atmosphere ................................. 14
Other Solar Radiation .................................. 23
The Sun’s Magnetic Field .............................. 25
The Sun–Earth Relationship ........................... 27
Alternative Models of the Sun ........................ 28
Web Notes .............................................. 31
2 Probing the Sun ............................................. 33
Early Solar Probes ...................................... 33
Recent Solar Probes .................................... 39
Future Solar Probes ..................................... 55
Web Notes .............................................. 58
3 Activity in the Photosphere ................................ 59
Granulation ............................................. 59
Sunspots ................................................ 62
Faculae, Flocculi and Plage ............................ 74
Web Notes .............................................. 77
4 Activity in the Chromosphere and Corona ............... 79
Spicules ................................................. 79
Prominences and Filaments ........................... 83
Solar Flares .............................................. 88
Coronal Mass Ejections ................................ 95
ix