Astronomy

SEPTEMBER 2017

16

times we didn’t

find E.T. p. 34

CASSINI’S GRAND FINALE AT SATURN p. 28

Vol. 45

Issue 9

The world’s best-selling astronomy magazine

Solving

mysterıes of

PLUTO

Unique landscapes,

geological activity,

and — maybe — an

underground ocean p. 22

HOW Flagstaff is

preserving dark skiesp. 54

SECRETS

of off-season globular clusters p. 50

NEW RESEARCH

BONUS ONLINE CONTENT CODE p. 4