Sky and Telescope - February 2017 - 57

BOOK REVIEW by S. N. Johnson-Roehr

Totality Changes Everything
SUN MOON EARTH: The History of Solar Eclipses from Omens of Doom to Einstein and Exoplanets
Tyler Nordgren
Basic Books, 2016
264 pages, ISBN 978-0-465-06092-4
$26.99, hardcover.
ASTRONOMER TYLER NORDGREN

(University of Redlands) has a knack
for connecting people with the sky.
Since 2005, he's been a member of the
National Park Service (NPS) Night-Sky
Team, working with NPS Rangers to
develop educational programs on darksky preservation and astronomy for
park visitors. His ﬁrst book, Stars Above,
Earth Below: A Guide to Astronomy in
the National Parks, showed readers how
to explore astronomy and planetary
science via familiar and much-loved
landscapes. And, thanks to his whimsical line of "astronomy travel" posters
(tylernordgren.com), inspired by the
aesthetics of New Deal WPA National
Park travel posters, the skies above
look both welcoming and exotic to new
astronomers - a manageable space,
but still one worth visiting. His work
combines to turn our fear of darkness
into a heady anticipation of night-time
wonders.
Nordgren's astronomy outreach has
always stressed friendliness and accessibility, so it comes as no surprise that
his new book, SUN MOON EARTH: The
History of Solar Eclipses from Omens of
Doom to Einstein and Exoplanets is as
entertaining as it is educational. On
August 21, 2017, millions of Americans (and thousands of international
visitors) will have the chance to see
their ﬁrst total solar eclipse. The path
of totality stretches across the United
States, from Oregon to South Carolina,
making this the most easily viewable
total solar eclipse in most of our lifetimes. Nordgren uses August's event as
a touchstone in this broad-reaching his-

tory of astronomy, meandering across
centuries and cultures, but always coming back to the upcoming eclipse. Total
solar eclipses are magniﬁcent spectacles, but as Nordgren demonstrates,
they're much more than that: throughout human history, we've used them to
evaluate and redeﬁne our place in the
universe. Will 2017's be any different?
There's plenty of science in SUN
MOON EARTH. Nordgren shows how
the Greeks used eclipses to measure the
size of the cosmos, how 19th-century
scientists worked out the Sun's composition thanks in part to observations
made during total solar eclipses, and
how 20th-century astronomers used
a total eclipse to test Einstein's theory
of relativity - all important topics
that reveal how studying the SunMoon-Earth relationship continues
to change our view of the world. But
the real strength of the book is Nordgren's wedding of eclipse science to the

emotional side of totality. Many of us
are self-proclaimed "corona-philes," or
eclipse chasers, watching the calendar
and waiting for our next chance to see
a total solar eclipse. Arguably, it's the
feelings of wonder and awe at totality
that keep us in the hunt, not the science
of Relativity. Yet affect and the cultural practices arising from it are often
dismissed by astronomers, derided as
mere superstition. Nordgren embraces
the emotions unleashed by totality -
uneasiness, euphoria, happiness, fear
- and shows how they push against the
boundaries of knowledge.
SUN MOON EARTH consists of
eight chapters and an introduction.
Each chapter discusses a different
historical problem, but the book as
a whole follows a long narrative arc,
from Nordgren's ﬁrst (missed) attempt
at total eclipse viewing in 1979, to his
next try in August 2017, and on into
a far distant future. Nordgren clearly
explains eclipse mechanics, providing a good introduction (or refresher
course) for anyone a little hazy on
the relationship between the Sun and
Moon shadows. He also provides a
short guide - including safety tips - to
viewing the upcoming total eclipse. If
you've been trying to get your friends
and family excited about this year's
event, give them this book. They'll
come away from reading it with a good
understanding of the science of eclipses
while undoubtedly being infected by
Nordgren's enthusiasm. And don't
be surprised if they turn into eclipse
chasers, too. As Nordgren points out,
totality changes everything.

¢ Observing Editor S. N. JOHNSONROEHR will be watching the August

2017 total solar eclipse from a front yard
in central Oregon.

s k y a n d t e l e s c o p e .c o m

* FEBRUARY 2017

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Sky and Telescope - February 2017

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