Sky & Telescope - September 2020 - 19
u EARTH (Top) Klyuchevskaya is the tallest and most active volcano on
the Kamchatka Peninsula of eastern Russia. It emitted this small plume
on January 10, 2018. The volcano has erupted more than 100 times in
the past 3,000 years.
u VENUS (Middle) Overlapping lava flows cover the flanks of Sapas
Mons and extend for hundreds of kilometers in this radar image. The
summit's two flat-topped mesas appear dark.
u MARS (Bottom) This mosaic shows Olympus Mons, the largest known
volcano in the solar system. It is more than twice as tall as Mount Everest.
orlds
The Red Planet is similarly endowed with shield volcanoes
and vast lava plains. It has two enormous volcanic provinces,
Tharsis and Elysium. It's within Tharsis that the biggest
shield volcanoes in the solar system are situated - with the
largest of them, Olympus Mons, rising to a summit elevation
of almost 22 km (14 miles). Expansive lava plains cover much
of the northern third of the planet. Some of these plains
formed in the last few hundred million years, but even the
very oldest terrains in the south likely also have a volcanic
origin. Indeed, Mars's volcanic record suggests a protracted
history of eruptions, both effusive and explosive, from
almost 4 billion years ago through as recently as the last few
million years.
Comparing these three worlds, we find some striking similarities. Volcanic activity has played a major role in shaping
their surfaces, has persisted for billions of years, and is widespread. Shield volcanoes and other types of edifices are the
rule, not the exception. These planets are clearly variations
on the same pattern. But as similar as these three surfaces
are, they paint a very different picture than those of Mercury
and the Moon, in terms of not only types but also distributions and ages of volcanic landforms.
E A RTH: JOSHUA STE V ENS A ND JEFF SCHM A LT Z / N ASA E A RTH
OBSERVATORY; V ENUS: N ASA / JPL; M A RS: N ASA / JPL / USGS
Exploring the Innermost Planet
It's hard to explore Mercury. Nestled deep in the Sun's gravity well, and orbiting too close to our star to safely point
a telescope at for very long, the innermost planet was the
last of the five rocky worlds to be visited with a flyby during
the opening act of our exploration of the inner solar system. When NASA's Mariner 10 spacecraft finally flew past
Mercury thrice in 1974 and 1975, it returned images of an
ancient, impact-scarred, and geologically dormant planet.
Then NASA's Messenger (Mercury Surface, Space Environment, Geochemistry, and Ranging) mission flew past
Mercury in 2008 and 2009 before entering orbit in 2011. The
craft's observations dramatically improved our understanding of the planet. Chief among Messenger's discoveries was
sk yandtelescope.org * SEP TEMBER 2 02 0
19
http://www.skyandtelescope.org
Sky & Telescope - September 2020
Table of Contents for the Digital Edition of Sky & Telescope - September 2020
Contents
Sky & Telescope - September 2020 - Cover1
Sky & Telescope - September 2020 - Cover2
Sky & Telescope - September 2020 - 1
Sky & Telescope - September 2020 - Contents
Sky & Telescope - September 2020 - 3
Sky & Telescope - September 2020 - 4
Sky & Telescope - September 2020 - 5
Sky & Telescope - September 2020 - 6
Sky & Telescope - September 2020 - 7
Sky & Telescope - September 2020 - 8
Sky & Telescope - September 2020 - 9
Sky & Telescope - September 2020 - 10
Sky & Telescope - September 2020 - 11
Sky & Telescope - September 2020 - 12
Sky & Telescope - September 2020 - 13
Sky & Telescope - September 2020 - 14
Sky & Telescope - September 2020 - 15
Sky & Telescope - September 2020 - 16
Sky & Telescope - September 2020 - 17
Sky & Telescope - September 2020 - 18
Sky & Telescope - September 2020 - 19
Sky & Telescope - September 2020 - 20
Sky & Telescope - September 2020 - 21
Sky & Telescope - September 2020 - 22
Sky & Telescope - September 2020 - 23
Sky & Telescope - September 2020 - 24
Sky & Telescope - September 2020 - 25
Sky & Telescope - September 2020 - 26
Sky & Telescope - September 2020 - 27
Sky & Telescope - September 2020 - 28
Sky & Telescope - September 2020 - 29
Sky & Telescope - September 2020 - 30
Sky & Telescope - September 2020 - 31
Sky & Telescope - September 2020 - 32
Sky & Telescope - September 2020 - 33
Sky & Telescope - September 2020 - 34
Sky & Telescope - September 2020 - 35
Sky & Telescope - September 2020 - 36
Sky & Telescope - September 2020 - 37
Sky & Telescope - September 2020 - 38
Sky & Telescope - September 2020 - 39
Sky & Telescope - September 2020 - 40
Sky & Telescope - September 2020 - 41
Sky & Telescope - September 2020 - 42
Sky & Telescope - September 2020 - 43
Sky & Telescope - September 2020 - 44
Sky & Telescope - September 2020 - 45
Sky & Telescope - September 2020 - 46
Sky & Telescope - September 2020 - 47
Sky & Telescope - September 2020 - 48
Sky & Telescope - September 2020 - 49
Sky & Telescope - September 2020 - 50
Sky & Telescope - September 2020 - 51
Sky & Telescope - September 2020 - 52
Sky & Telescope - September 2020 - 53
Sky & Telescope - September 2020 - 54
Sky & Telescope - September 2020 - 55
Sky & Telescope - September 2020 - 56
Sky & Telescope - September 2020 - 57
Sky & Telescope - September 2020 - 58
Sky & Telescope - September 2020 - 59
Sky & Telescope - September 2020 - 60
Sky & Telescope - September 2020 - 61
Sky & Telescope - September 2020 - 62
Sky & Telescope - September 2020 - 63
Sky & Telescope - September 2020 - 64
Sky & Telescope - September 2020 - 65
Sky & Telescope - September 2020 - 66
Sky & Telescope - September 2020 - 67
Sky & Telescope - September 2020 - 68
Sky & Telescope - September 2020 - 69
Sky & Telescope - September 2020 - 70
Sky & Telescope - September 2020 - 71
Sky & Telescope - September 2020 - 72
Sky & Telescope - September 2020 - 73
Sky & Telescope - September 2020 - 74
Sky & Telescope - September 2020 - 75
Sky & Telescope - September 2020 - 76
Sky & Telescope - September 2020 - 77
Sky & Telescope - September 2020 - 78
Sky & Telescope - September 2020 - 79
Sky & Telescope - September 2020 - 80
Sky & Telescope - September 2020 - 81
Sky & Telescope - September 2020 - 82
Sky & Telescope - September 2020 - 83
Sky & Telescope - September 2020 - 84
Sky & Telescope - September 2020 - Cover3
Sky & Telescope - September 2020 - Cover4
https://www.nxtbook.com/nxtbooks/aas/st_202410
https://www.nxtbook.com/nxtbooks/aas/st_202409
https://www.nxtbook.com/nxtbooks/aas/st_202408
https://www.nxtbook.com/nxtbooks/aas/st_202407
https://www.nxtbook.com/nxtbooks/aas/st_202406
https://www.nxtbook.com/nxtbooks/aas/st_202405
https://www.nxtbook.com/nxtbooks/aas/st_202404_qr
https://www.nxtbook.com/nxtbooks/aas/st_202404
https://www.nxtbook.com/nxtbooks/aas/st_202403
https://www.nxtbook.com/nxtbooks/aas/st_202402
https://www.nxtbook.com/nxtbooks/aas/st_202401_aus
https://www.nxtbook.com/nxtbooks/aas/st_202401
https://www.nxtbook.com/nxtbooks/aas/st_202312_aus
https://www.nxtbook.com/nxtbooks/aas/st_202312
https://www.nxtbook.com/nxtbooks/aas/st_202311
https://www.nxtbook.com/nxtbooks/aas/st_202310
https://www.nxtbook.com/nxtbooks/aas/st_202309
https://www.nxtbook.com/nxtbooks/aas/st_202308
https://www.nxtbook.com/nxtbooks/aas/st_202307
https://www.nxtbook.com/nxtbooks/aas/st_202306
https://www.nxtbook.com/nxtbooks/aas/st_202305
https://www.nxtbook.com/nxtbooks/aas/st_202304
https://www.nxtbook.com/nxtbooks/aas/st_202304_qr
https://www.nxtbook.com/nxtbooks/aas/st_202303
https://www.nxtbook.com/nxtbooks/aas/st_202302
https://www.nxtbook.com/nxtbooks/aas/st_202301
https://www.nxtbook.com/nxtbooks/aas/st_202212
https://www.nxtbook.com/nxtbooks/aas/st_202211
https://www.nxtbook.com/nxtbooks/aas/st_202210
https://www.nxtbook.com/nxtbooks/aas/st_202209
https://www.nxtbook.com/nxtbooks/aas/st_202208
https://www.nxtbook.com/nxtbooks/aas/st_202207
https://www.nxtbook.com/nxtbooks/aas/st_202206
https://www.nxtbook.com/nxtbooks/aas/st_202205
https://www.nxtbook.com/nxtbooks/aas/st_202204
https://www.nxtbook.com/nxtbooks/aas/st_202203
https://www.nxtbook.com/nxtbooks/aas/st_202202
https://www.nxtbook.com/nxtbooks/aas/st_202201
https://www.nxtbook.com/nxtbooks/aas/st_202112
https://www.nxtbook.com/nxtbooks/aas/st_202111
https://www.nxtbook.com/nxtbooks/aas/st_202110
https://www.nxtbook.com/nxtbooks/aas/st_202109
https://www.nxtbook.com/nxtbooks/aas/st_202108
https://www.nxtbook.com/nxtbooks/aas/st_202107
https://www.nxtbook.com/nxtbooks/aas/st_202106
https://www.nxtbook.com/nxtbooks/aas/st_202105
https://www.nxtbook.com/nxtbooks/aas/st_202104
https://www.nxtbook.com/nxtbooks/aas/st_202103
https://www.nxtbook.com/nxtbooks/aas/st_202102
https://www.nxtbook.com/nxtbooks/aas/st_202101
https://www.nxtbook.com/nxtbooks/aas/skywatch_2021
https://www.nxtbook.com/nxtbooks/aas/st_202012
https://www.nxtbook.com/nxtbooks/aas/st_202011
https://www.nxtbook.com/nxtbooks/aas/st_202010
https://www.nxtbook.com/nxtbooks/aas/st_202009
https://www.nxtbook.com/nxtbooks/aas/st_202008
https://www.nxtbook.com/nxtbooks/aas/st_202007
https://www.nxtbook.com/nxtbooks/aas/st_202006
https://www.nxtbook.com/nxtbooks/aas/st_202005
https://www.nxtbook.com/nxtbooks/aas/st_202004
https://www.nxtbook.com/nxtbooks/aas/st_202003
https://www.nxtbook.com/nxtbooks/aas/st_202002
https://www.nxtbook.com/nxtbooks/aas/st_202001
https://www.nxtbook.com/nxtbooks/aas/st_201912
https://www.nxtbook.com/nxtbooks/aas/st_201911
https://www.nxtbook.com/nxtbooks/aas/st_201910
https://www.nxtbook.com/nxtbooks/aas/st_201909
https://www.nxtbook.com/nxtbooks/aas/st_201908
https://www.nxtbook.com/nxtbooks/aas/st_201907
https://www.nxtbook.com/nxtbooks/aas/st_201906
https://www.nxtbook.com/nxtbooks/aas/st_201905
https://www.nxtbook.com/nxtbooks/aas/st_201904
https://www.nxtbook.com/nxtbooks/aas/st_201903
https://www.nxtbook.com/nxtbooks/aas/st_201902
https://www.nxtbook.com/nxtbooks/aas/st_201901
https://www.nxtbook.com/nxtbooks/aas/st_201812
https://www.nxtbook.com/nxtbooks/aas/st_201811
https://www.nxtbook.com/nxtbooks/aas/st_201810
https://www.nxtbook.com/nxtbooks/aas/st_201809
https://www.nxtbook.com/nxtbooks/aas/st_201808
https://www.nxtbook.com/nxtbooks/aas/st_201807
https://www.nxtbook.com/nxtbooks/aas/st_201806
https://www.nxtbook.com/nxtbooks/aas/st_201805
https://www.nxtbook.com/nxtbooks/aas/st_201804
https://www.nxtbook.com/nxtbooks/aas/st_201803
https://www.nxtbook.com/nxtbooks/aas/st_201802
https://www.nxtbook.com/nxtbooks/aas/st_201801
https://www.nxtbook.com/nxtbooks/aas/st_201712
https://www.nxtbook.com/nxtbooks/aas/st_201711
https://www.nxtbook.com/nxtbooks/aas/st_201710
https://www.nxtbook.com/nxtbooks/aas/st_201709
https://www.nxtbook.com/nxtbooks/aas/st_201708
https://www.nxtbook.com/nxtbooks/aas/st_201707
https://www.nxtbook.com/nxtbooks/aas/st_201706
https://www.nxtbook.com/nxtbooks/aas/st_201705
https://www.nxtbook.com/nxtbooks/aas/st_201704
https://www.nxtbook.com/nxtbooks/aas/st_201703
https://www.nxtbook.com/nxtbooks/aas/st_201702
https://www.nxtbook.com/nxtbooks/aas/st_201701
https://www.nxtbook.com/nxtbooks/aas/st_201612
https://www.nxtbook.com/nxtbooks/aas/st_201611
https://www.nxtbook.com/nxtbooks/aas/st_201610
https://www.nxtbook.com/nxtbooks/aas/st_201609
https://www.nxtbook.com/nxtbooks/aas/st_201608
https://www.nxtbook.com/nxtbooks/aas/st_201607
https://www.nxtbook.com/nxtbooks/aas/st_201606
https://www.nxtbook.com/nxtbooks/aas/st_201605
https://www.nxtbook.com/nxtbooks/aas/st_201604
https://www.nxtbook.com/nxtbooks/aas/st_201603
https://www.nxtbook.com/nxtbooks/aas/st_201602
https://www.nxtbook.com/nxtbooks/aas/st_201601
https://www.nxtbook.com/nxtbooks/aas/st_201512
https://www.nxtbook.com/nxtbooks/aas/st_201511
https://www.nxtbook.com/nxtbooks/aas/st_201510
https://www.nxtbook.com/nxtbooks/aas/st_201509
https://www.nxtbook.com/nxtbooks/aas/st_201508
https://www.nxtbook.com/nxtbooks/aas/st_201507
https://www.nxtbook.com/nxtbooks/aas/st_201506
https://www.nxtbook.com/nxtbooks/aas/st_201505
https://www.nxtbook.com/nxtbooks/aas/st_201504
https://www.nxtbook.com/nxtbooks/aas/st_201503
https://www.nxtbook.com/nxtbooks/aas/st_201502
https://www.nxtbook.com/nxtbooks/aas/st_201501
https://www.nxtbook.com/nxtbooks/aas/st_201412
https://www.nxtbook.com/nxtbooks/aas/st_201411
https://www.nxtbook.com/nxtbooks/aas/st_201410
https://www.nxtbook.com/nxtbooks/aas/st_201409
https://www.nxtbook.com/nxtbooks/aas/st_201408
https://www.nxtbook.com/nxtbooks/aas/st_201407
https://www.nxtbook.com/nxtbooks/aas/st_201406
https://www.nxtbook.com/nxtbooks/aas/st_mars
https://www.nxtbook.com/nxtbooks/aas/st_201405
https://www.nxtbook.com/nxtbooks/aas/st_201404
https://www.nxtbook.com/nxtbooks/aas/st_201403
https://www.nxtbook.com/nxtbooks/aas/st_201402
https://www.nxtbook.com/nxtbooks/aas/st_201401
https://www.nxtbook.com/nxtbooks/aas/st_201312
https://www.nxtbook.com/nxtbooks/aas/st_201311
https://www.nxtbook.com/nxtbooks/aas/st_201310
https://www.nxtbook.com/nxtbooks/aas/st_201309
https://www.nxtbook.com/nxtbooks/aas/st_201308
https://www.nxtbook.com/nxtbooks/aas/st_201307
https://www.nxtbook.com/nxtbooks/aas/st_201306
https://www.nxtbook.com/nxtbooks/aas/st_201305
https://www.nxtbook.com/nxtbooks/aas/st_201304
https://www.nxtbook.com/nxtbooks/aas/st_201303
https://www.nxtbook.com/nxtbooks/aas/st_201302
https://www.nxtbook.com/nxtbooks/aas/st_201301
https://www.nxtbook.com/nxtbooks/aas/st_201212
https://www.nxtbook.com/nxtbooks/aas/st_201211
https://www.nxtbook.com/nxtbooks/aas/st_201210
https://www.nxtbook.com/nxtbooks/aas/st_201209
https://www.nxtbook.com/nxtbooks/aas/st_201208
https://www.nxtbook.com/nxtbooks/aas/st_201207
https://www.nxtbook.com/nxtbooks/aas/st_201206
https://www.nxtbook.com/nxtbooks/aas/st_201205
https://www.nxtbook.com/nxtbooks/aas/st_201204
https://www.nxtbook.com/nxtbooks/aas/st_201203
https://www.nxtbook.com/nxtbooks/aas/st_201202
https://www.nxtbook.com/nxtbooks/aas/st_201201
https://www.nxtbook.com/nxtbooks/aas/st_201112
https://www.nxtbook.com/nxtbooks/aas/st_201111
https://www.nxtbook.com/nxtbooks/aas/st_201110
https://www.nxtbook.com/nxtbooks/aas/st_201109
https://www.nxtbook.com/nxtbooks/aas/st_201108
https://www.nxtbook.com/nxtbooks/aas/st_201107
https://www.nxtbook.com/nxtbooks/aas/st_201106
https://www.nxtbook.com/nxtbooks/aas/st_201105
https://www.nxtbook.com/nxtbooks/aas/st_201104
https://www.nxtbook.com/nxtbooks/aas/st_201103
https://www.nxtbook.com/nxtbooks/aas/st_201102
https://www.nxtbook.com/nxtbooks/aas/st_201101
https://www.nxtbook.com/nxtbooks/aas/st_201012
https://www.nxtbook.com/nxtbooks/aas/st_201011
https://www.nxtbook.com/nxtbooks/aas/st_201010
https://www.nxtbook.com/nxtbooks/aas/st_201009
https://www.nxtbook.com/nxtbooks/aas/st_201008
https://www.nxtbook.com/nxtbooks/aas/st_201007
https://www.nxtbook.com/nxtbooks/aas/st_201006
https://www.nxtbook.com/nxtbooks/aas/st_201005
https://www.nxtbook.com/nxtbooks/aas/st_201004
https://www.nxtbook.com/nxtbooks/aas/st_201003
https://www.nxtbook.com/nxtbooks/aas/st_201002
https://www.nxtbook.com/nxtbooks/aas/st_201001
https://www.nxtbookmedia.com