Sky and Telescope - September 2018 - 4

SPECTRUM

by Peter Tyson

Returning to Venus

The Essential Guide to Astronomy
Founded in 1941 by Charles A. Federer, Jr.
and Helen Spence Federer

AMERICAN PLANETARY SCIENTISTS who specialize in Venus are a

Editor in Chief

Editorial Correspondence (including
permissions, partnerships, and content licensing):
Sky & Telescope, 90 Sherman St., Cambridge,
MA 02140-3264, USA. Phone: 617-864-7360.
E-mail: editors@skyandtelescope.com. Website:
skyandtelescope.com. Unsolicited proposals,
manuscripts, photographs, and electronic images
are welcome, but a stamped, self-addressed
envelope must be provided to guarantee their
return; see our guidelines for contributors at
skyandtelescope.com.

4

Advertising Information: Tim Allen
773-551-0397, Fax: 617-864-6117.
E-mail: tallen@skyandtelescope.com
Web: skyandtelescope.com/advertising
Customer Service: Magazine customer
service and change-of-address notices:
skyandtelescope@emailcustomerservice.com
Phone toll-free U.S. and Canada:
800-253-0245.
Outside the U.S. and Canada: 386-597-4387.

S E P TE M B E R 2 018 * SK Y & TELESCOPE

EDITORIAL
Editor in Chief Peter Tyson
Senior Editors J. Kelly Beatty, Alan M. MacRobert
Equipment Editor Sean Walker
Science Editor Camille M. Carlisle
News Editor Monica Young
Associate Editor S. N. Johnson-Roehr
Observing Editor Diana Hannikainen
Project Coordinator Bud Sadler
Digital Content Strategist Janine Myszka
Senior Contributing Editors
Robert Naeye, Roger W. Sinnott
Contributing Editors
Howard Banich, Jim Bell, Trudy Bell, John E. Bortle,
Greg Bryant, Thomas A. Dobbins, Alan Dyer,
Tom Field, Tony Flanders, Ted Forte, Sue French,
Steve Gottlieb, David Grinspoon, Ken Hewitt-White,
Johnny Horne, Bob King, Emily Lakdawalla,
Rod Mollise, James Mullaney, Donald W. Olson,
Jerry Oltion, Joe Rao, Dean Regas, Fred Schaaf,
Govert Schilling, William Sheehan, Mike Simmons,
Mathew Wedel, Alan Whitman, Charles A. Wood
Contributing Photographers
P. K. Chen, Akira Fujii, Robert Gendler,
Babak Tafreshi

ART & DESIGN
Art Director Terri Dubé
Illustration Director Gregg Dinderman
Illustrator Leah Tiscione
ADVERTISING
VP, Advertising Sales Kevin D. Smith
Advertising Sales Director Tim Allen
Advertising Coordinator Connie Kostrzewa

N ASA / JPL- CA LTECH

disheartened bunch, and understandably so: NASA hasn't dispatched a dedicated mission to our sister planet in almost three
decades. These scientists don't begrudge spacecraft the agency has
sent during that time to Mars, Saturn, Pluto, and other destinations. They'd be the first to say that those explorations have made fantastic
discoveries and conducted stupefying science. They just want a piece of the pie.
To me, and I'm hardly alone in this, the chief reason why NASA should
return to Venus can be encapsulated in one word: exoplanets. The number of
worlds in other solar systems that we've identified now stands in
the thousands, thanks to the Kepler space telescope. And the
newly launched Transiting Exoplanet Survey Satellite (TESS) is
expected to find hundreds more (S&T: March 2018, p. 22).
While the Holy Grail of exoplanet studies is to locate Earthlike worlds, many of the rocky bodies around other stars are
more likely to be akin to Venus than to our beloved Gaea. The
transit method that both Kepler and TESS rely on is biased toward
detecting planets that are close to their host stars rather than farther away.
As such, we may have more Earth-size planets to study that are interior to the
vaunted habitable zone than those that lie more comfortably within it, as we do.
What those discouraged Venusian experts keep harping on is: How are we
to understand all these Venus analogs if we don't have a good grasp of Venus
itself? As astrobiologist (and S&T columnist) David Grinspoon says in our
cover story on page 14, "We have no hope of making sense of those [exo-Venus]
observations without getting a handle on the Venus-Earth dichotomy."
Many basic questions about our twin remain unanswered: Why did Venus
evolve into a lifeless hell instead of the living heaven that is Mother Earth? Billions of years ago, Venus might have had oceans; today its surface is hot enough
to melt lead. Where did the water go? Did the planet ever have plate tectonism?
Perhaps most of interest in terms of exoplanet research, was it ever habitable?
To attempt to answer such questions, and to be able to correctly interpret
data we gather about extra-solar Venuses, it's imperative that we return to our
toxic twin and further investigate it - above, on, and below its surface.
Fortunately, the European and Japanese space agencies have kept Venus studies
alive with their recent (and highly successful) Venus Express and Akatsuki missions. And Europe, Russia, and India are researching future sorties. Does NASA
really want to be left behind in the on-site examination of our solar system's
natural exoplanet laboratory? Not just planetary scientists,
but exoplanet astronomers, hang on the answer.

F+W MEDIA
Chief Executive Officer Gregory J. Osberg
Chief Financial Officer Kenneth Kharbanda
SVP / GM - F+W Fine Art, Writing, Outdoors &
Small Business Groups Ray Chelstowski
Managing Director - F+W International
James Woollam
VP, General Counsel Robert Sporn
VP, Human Resources Gigi Healy
VP, Manufacturing & Logistics Phil Graham
Newsstand Sales Scott T. Hill, Scott.hill@procirc.com

Visit shopatsky.com
Your source for the best astronomy resources
Shop at Sky customer service:
skyprodservice@skyandtelescope.com
888-253-0230.
Subscription Rates: U.S. and possessions:
$42.95 per year (12 issues);
Canada: $49.95 (including GST);
all other countries: $61.95, by expedited delivery.
All prices are in U.S. dollars.

Newsstand and Retail Distribution:
Curtis Circulation Co., 201-634-7400.
The following are registered trademarks
of F+W Media, Inc.: Sky & Telescope and
logo, Sky and Telescope, The Essential Guide
to Astronomy, Skyline, Sky Publications,
skyandtelescope.com, skypub.com,
SkyWatch, Scanning the Skies,
Night Sky, SkyWeek, and ESSCO.


http://www.shopatsky.com http://www.skyandtelescope.com/advertising http://www.skyandtelescope.com http://www.skyandtelescope.com http://www.skypub.com http://www.skyandtelescope.com

Table of Contents for the Digital Edition of Sky and Telescope - September 2018

Contents
Sky and Telescope - September 2018 - Cover1
Sky and Telescope - September 2018 - Cover2
Sky and Telescope - September 2018 - 1
Sky and Telescope - September 2018 - Contents
Sky and Telescope - September 2018 - 3
Sky and Telescope - September 2018 - 4
Sky and Telescope - September 2018 - 5
Sky and Telescope - September 2018 - 6
Sky and Telescope - September 2018 - 7
Sky and Telescope - September 2018 - 8
Sky and Telescope - September 2018 - 9
Sky and Telescope - September 2018 - 10
Sky and Telescope - September 2018 - 11
Sky and Telescope - September 2018 - 12
Sky and Telescope - September 2018 - 13
Sky and Telescope - September 2018 - 14
Sky and Telescope - September 2018 - 15
Sky and Telescope - September 2018 - 16
Sky and Telescope - September 2018 - 17
Sky and Telescope - September 2018 - 18
Sky and Telescope - September 2018 - 19
Sky and Telescope - September 2018 - 20
Sky and Telescope - September 2018 - 21
Sky and Telescope - September 2018 - 22
Sky and Telescope - September 2018 - 23
Sky and Telescope - September 2018 - 24
Sky and Telescope - September 2018 - 25
Sky and Telescope - September 2018 - 26
Sky and Telescope - September 2018 - 27
Sky and Telescope - September 2018 - 28
Sky and Telescope - September 2018 - 29
Sky and Telescope - September 2018 - 30
Sky and Telescope - September 2018 - 31
Sky and Telescope - September 2018 - 32
Sky and Telescope - September 2018 - 33
Sky and Telescope - September 2018 - 34
Sky and Telescope - September 2018 - 35
Sky and Telescope - September 2018 - 36
Sky and Telescope - September 2018 - 37
Sky and Telescope - September 2018 - 38
Sky and Telescope - September 2018 - 39
Sky and Telescope - September 2018 - 40
Sky and Telescope - September 2018 - 41
Sky and Telescope - September 2018 - 42
Sky and Telescope - September 2018 - 43
Sky and Telescope - September 2018 - 44
Sky and Telescope - September 2018 - 45
Sky and Telescope - September 2018 - 46
Sky and Telescope - September 2018 - 47
Sky and Telescope - September 2018 - 48
Sky and Telescope - September 2018 - 49
Sky and Telescope - September 2018 - 50
Sky and Telescope - September 2018 - 51
Sky and Telescope - September 2018 - 52
Sky and Telescope - September 2018 - 53
Sky and Telescope - September 2018 - 54
Sky and Telescope - September 2018 - 55
Sky and Telescope - September 2018 - 56
Sky and Telescope - September 2018 - 57
Sky and Telescope - September 2018 - 58
Sky and Telescope - September 2018 - 59
Sky and Telescope - September 2018 - 60
Sky and Telescope - September 2018 - 61
Sky and Telescope - September 2018 - 62
Sky and Telescope - September 2018 - 63
Sky and Telescope - September 2018 - 64
Sky and Telescope - September 2018 - 65
Sky and Telescope - September 2018 - 66
Sky and Telescope - September 2018 - 67
Sky and Telescope - September 2018 - 68
Sky and Telescope - September 2018 - 69
Sky and Telescope - September 2018 - 70
Sky and Telescope - September 2018 - 71
Sky and Telescope - September 2018 - 72
Sky and Telescope - September 2018 - 73
Sky and Telescope - September 2018 - 74
Sky and Telescope - September 2018 - 75
Sky and Telescope - September 2018 - 76
Sky and Telescope - September 2018 - 77
Sky and Telescope - September 2018 - 78
Sky and Telescope - September 2018 - 79
Sky and Telescope - September 2018 - 80
Sky and Telescope - September 2018 - 81
Sky and Telescope - September 2018 - 82
Sky and Telescope - September 2018 - 83
Sky and Telescope - September 2018 - 84
Sky and Telescope - September 2018 - Cover3
Sky and Telescope - September 2018 - Cover4
http://www.nxtbook.com/nxtbooks/newtrack/st_201811
http://www.nxtbook.com/nxtbooks/newtrack/st_201810
http://www.nxtbook.com/nxtbooks/newtrack/st_201809
http://www.nxtbook.com/nxtbooks/newtrack/st_201808
http://www.nxtbook.com/nxtbooks/newtrack/st_201807
http://www.nxtbook.com/nxtbooks/newtrack/st_201806
http://www.nxtbook.com/nxtbooks/newtrack/st_201805
http://www.nxtbook.com/nxtbooks/newtrack/st_201804
http://www.nxtbook.com/nxtbooks/newtrack/st_201803
http://www.nxtbook.com/nxtbooks/newtrack/st_201802
http://www.nxtbook.com/nxtbooks/newtrack/st_201801
http://www.nxtbook.com/nxtbooks/newtrack/st_201712
http://www.nxtbook.com/nxtbooks/newtrack/st_201711
http://www.nxtbook.com/nxtbooks/newtrack/st_201710
http://www.nxtbook.com/nxtbooks/newtrack/st_201709
http://www.nxtbook.com/nxtbooks/newtrack/st_201708
http://www.nxtbook.com/nxtbooks/newtrack/st_201707
http://www.nxtbook.com/nxtbooks/newtrack/st_201706
http://www.nxtbook.com/nxtbooks/newtrack/st_201705
http://www.nxtbook.com/nxtbooks/newtrack/st_201704
http://www.nxtbook.com/nxtbooks/newtrack/st_201703
http://www.nxtbook.com/nxtbooks/newtrack/st_201702
http://www.nxtbook.com/nxtbooks/newtrack/st_201701
http://www.nxtbook.com/nxtbooks/newtrack/st_201612
http://www.nxtbook.com/nxtbooks/newtrack/st_201611
http://www.nxtbook.com/nxtbooks/newtrack/st_201610
http://www.nxtbook.com/nxtbooks/newtrack/st_201609
http://www.nxtbook.com/nxtbooks/newtrack/st_201608
http://www.nxtbook.com/nxtbooks/newtrack/st_201607
http://www.nxtbook.com/nxtbooks/newtrack/st_201606
http://www.nxtbook.com/nxtbooks/newtrack/st_201605
http://www.nxtbook.com/nxtbooks/newtrack/st_201604
http://www.nxtbook.com/nxtbooks/newtrack/st_201603
http://www.nxtbook.com/nxtbooks/newtrack/st_201602
http://www.nxtbook.com/nxtbooks/newtrack/st_201601
http://www.nxtbook.com/nxtbooks/newtrack/st_201512
http://www.nxtbook.com/nxtbooks/newtrack/st_201511
http://www.nxtbook.com/nxtbooks/newtrack/st_201510
http://www.nxtbook.com/nxtbooks/newtrack/st_201509
http://www.nxtbook.com/nxtbooks/newtrack/st_201508
http://www.nxtbook.com/nxtbooks/newtrack/st_201507
http://www.nxtbook.com/nxtbooks/newtrack/st_201506
http://www.nxtbook.com/nxtbooks/newtrack/st_201505
http://www.nxtbook.com/nxtbooks/newtrack/st_201504
http://www.nxtbook.com/nxtbooks/newtrack/st_201503
http://www.nxtbook.com/nxtbooks/newtrack/st_201502
http://www.nxtbook.com/nxtbooks/newtrack/st_201501
http://www.nxtbook.com/nxtbooks/newtrack/st_201412
http://www.nxtbook.com/nxtbooks/newtrack/st_201411
http://www.nxtbook.com/nxtbooks/newtrack/st_201410
http://www.nxtbook.com/nxtbooks/newtrack/st_201409
http://www.nxtbook.com/nxtbooks/newtrack/st_201408
http://www.nxtbook.com/nxtbooks/newtrack/st_mars
http://www.nxtbook.com/nxtbooks/newtrack/st_201407
http://www.nxtbook.com/nxtbooks/newtrack/st_201406
http://www.nxtbook.com/nxtbooks/newtrack/st_201405
http://www.nxtbook.com/nxtbooks/newtrack/st_201404
http://www.nxtbook.com/nxtbooks/newtrack/st_201403
http://www.nxtbook.com/nxtbooks/newtrack/st_201402
http://www.nxtbook.com/nxtbooks/newtrack/st_201401
http://www.nxtbook.com/nxtbooks/newtrack/st_201312
http://www.nxtbook.com/nxtbooks/newtrack/st_201311
http://www.nxtbook.com/nxtbooks/newtrack/st_201310
http://www.nxtbook.com/nxtbooks/newtrack/st_201309
http://www.nxtbook.com/nxtbooks/newtrack/st_201308
http://www.nxtbook.com/nxtbooks/newtrack/st_201307
http://www.nxtbook.com/nxtbooks/newtrack/st_201306
http://www.nxtbook.com/nxtbooks/newtrack/st_201305
http://www.nxtbook.com/nxtbooks/newtrack/st_201304
http://www.nxtbook.com/nxtbooks/newtrack/st_201303
http://www.nxtbook.com/nxtbooks/newtrack/st_201302
http://www.nxtbook.com/nxtbooks/newtrack/st_201301
http://www.nxtbook.com/nxtbooks/newtrack/st_201212
http://www.nxtbook.com/nxtbooks/newtrack/st_201211
http://www.nxtbook.com/nxtbooks/newtrack/st_201210
http://www.nxtbook.com/nxtbooks/newtrack/st_201209
http://www.nxtbook.com/nxtbooks/newtrack/st_201208
http://www.nxtbook.com/nxtbooks/newtrack/st_201207
http://www.nxtbook.com/nxtbooks/newtrack/st_201206
http://www.nxtbook.com/nxtbooks/newtrack/st_201205
http://www.nxtbook.com/nxtbooks/newtrack/st_201204
http://www.nxtbook.com/nxtbooks/newtrack/st_201203
http://www.nxtbook.com/nxtbooks/newtrack/st_201202
http://www.nxtbook.com/nxtbooks/newtrack/st_201201
http://www.nxtbook.com/nxtbooks/newtrack/st_201112
http://www.nxtbook.com/nxtbooks/newtrack/st_201111
http://www.nxtbook.com/nxtbooks/newtrack/st_201110
http://www.nxtbook.com/nxtbooks/newtrack/st_201109
http://www.nxtbook.com/nxtbooks/newtrack/st_201108
http://www.nxtbook.com/nxtbooks/newtrack/st_201107
http://www.nxtbook.com/nxtbooks/newtrack/st_201106
http://www.nxtbook.com/nxtbooks/newtrack/st_201105
http://www.nxtbook.com/nxtbooks/newtrack/st_201104
http://www.nxtbook.com/nxtbooks/newtrack/st_201103
http://www.nxtbook.com/nxtbooks/newtrack/st_201102
http://www.nxtbook.com/nxtbooks/newtrack/st_201101
http://www.nxtbook.com/nxtbooks/newtrack/st_201012
http://www.nxtbook.com/nxtbooks/newtrack/st_201011
http://www.nxtbook.com/nxtbooks/newtrack/st_201010
http://www.nxtbook.com/nxtbooks/newtrack/st_201009
http://www.nxtbook.com/nxtbooks/newtrack/newtrack_st_201009
http://www.nxtbook.com/nxtbooks/newtrack/st_201008_v2
http://www.nxtbook.com/nxtbooks/newtrack/st_201008
http://www.nxtbook.com/nxtbooks/newtrack/st_201007
http://www.nxtbook.com/nxtbooks/newtrack/st_201005_v2
http://www.nxtbook.com/nxtbooks/newtrack/st_201006
http://www.nxtbook.com/nxtbooks/newtrack/st_201005
http://www.nxtbook.com/nxtbooks/newtrack/st_201004
http://www.nxtbook.com/nxtbooks/newtrack/st_201003v4
http://www.nxtbook.com/nxtbooks/newtrack/st_201003v3
http://www.nxtbook.com/nxtbooks/newtrack/st_201003v2
http://www.nxtbook.com/nxtbooks/newtrack/st_201003
http://www.nxtbook.com/nxtbooks/newtrack/st_201002
http://www.nxtbook.com/nxtbooks/newtrack/st_201001
http://www.nxtbookMEDIA.com