Sky & Telescope - April 2022 - 19

NO SMALL FRY Ganymede, the largest moon in the solar system, beats out Mercury in size, with Callisto not far behind. But both satellites are far
less dense than the Iron Planet or even Earth's Moon. Europa, just smaller than the Moon, has only a slightly lower density than our satellite.
CALLISTO
4,821 km
GANYMEDE
5,262 km
EUROPA
3,122 km
MOON
3,475 km
MERCURY
4,879 km
350
300
250
200
150
100
50
330.2
148.2
107.6
48
Density
(kg/m3)
=100 kg/m3
1,830
1,940
3,010
3,340
5,427
73.5
CLOSE KIN In kilometers, the Moon lies closer
to Earth than the Galileans do to Jupiter. But in
terms of the host planet's size, the Galileans are much
closer: Ganymede lies 15 Jupiter radii away, whereas the
Moon lies 60 Earth radii away. (Distances are shortened by a factor
of 5 with respect to the planets' sizes, in order to fit on the page.)
384,000 km
Moon
1,883,000 km
Callisto
1,070,000 km
Ganymede
671,000 km
Europa
EARTH
4 km
EUROPA
CALLISTO
GANYMEDE
100 km
100 km
HOW MUCH WATER? Estimates vary, but the Galilean
oceans could easily be 25 times deeper than the average
depth of Earth's seas. (Earth's deepest point is 11 km, in
the western Pacific's Mariana Trench.)
300 km
sk yand tele scope .o r g * APRIL 2022 19
INFOGRAPHIC: TERRI DUBÉ / S&T; EUROPA ICON:
KAYLA VALENCIA / THE NOUN PROJECT; JUPITER
ICON: VICTORULER / THE NOUN PROJECT
Mass (1021 kg)

http://skyandtelescope.org

Sky & Telescope - April 2022

Table of Contents for the Digital Edition of Sky & Telescope - April 2022

Contents
Sky & Telescope - April 2022 - Cover1
Sky & Telescope - April 2022 - Cover2
Sky & Telescope - April 2022 - 1
Sky & Telescope - April 2022 - Contents
Sky & Telescope - April 2022 - 3
Sky & Telescope - April 2022 - 4
Sky & Telescope - April 2022 - 5
Sky & Telescope - April 2022 - 6
Sky & Telescope - April 2022 - 7
Sky & Telescope - April 2022 - 8
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