Astronomy - 06.2019

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4 ASTRONOMY • JUNE 2019

20 COVER STORY

Tension at the heart
of cosmology
Astronomers have found two
different — and mutually exclusive
— values for the expansion rate of
the universe. ROBERT NAEYE

28

New Horizons swings
past Ultima Thule
The historic encounter gave us
our first close-up look at a Kuiper
Belt object, the most distant body
we have ever explored.
DAVID J. EICHER

36

Sky This Month
Jupiter dazzles all night.
MARTIN RATCLIFFE AND

ALISTER LING

38

StarDome and

Path of the Planets

RICHARD TALCOTT;

ILLUSTRATIONS BY ROEN KELLY

44

The Outer Limits universe

Objects briefly seen on television

over 50 years ago make terrific

targets for today’s amateur

astronomers. MICHAEL E. BAKICH

50

The paper trail

of astronomy

Transient treasures of word and

art show that our science has a

rich and colorful past.

RAYMOND SHUBINSKI

56

Mission complete for

Opportunity rover

After 15 years exploring the Red

Planet, the Mars Exploration

Rover mission has ended.

ALISON KLESMAN AND JOHN WENZ

60

The story behind

Stellarvue

From the start, this company’s

goal was the perfect telescope.

TONY HALLAS

68

Ask Astro

Solar storms.

COLUMNS

Strange Universe 12

BOB BERMAN

Binocular Universe 14

PHIL HARRINGTON

Observing Basics 16

GLENN CHAPLE

Secret Sky 64

STEPHEN JAMES O’MEARA

QUANTUM GRAVITY

Snapshot 9

Astro News 10

IN EVERY ISSUE

From the Editor 6

Astro Letters 8

Advertiser Index 65

New Products 66

Reader Gallery 70

Breakthrough 74

FEATURES

JUNE 2019

VOL. 47, NO. 6

28

Astronomy (ISSN 0091-6358, USPS 531-350)

is published monthly by Kalmbach Media

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ESA/HUBBLE & NASA

ON THE COVER

Expansion of the universe governs

how galaxies like the Antennae

(NGC 4038–9) interact.

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