- FROM THE EDGE
One of the most heav-
ily cratered objects
in our solar system is
Jupiter’s moon Callisto,
discovered by Galileo
in the 17th century.
Valhalla, a crater on
this moon’s surface
named for the home
of fallen warriors in
Norse mythology, is
the largest at roughly
2,500 miles in diam-
eter. Unlike Callisto,
Earth is shielded from
space rocks by its
atmosphere but has
nonetheless had its
share of impacts. If
you want the feeling
of standing inside the
rim of Valhalla, you can
visit some of the 190
confirmed craters on
our planet created by
meteorites. The largest
is Vredefort crater, a
rumpled ring of moun-
tains in South Africa
some one hundred
miles across. You can
also check out the
smaller, younger, and
more intact Pingualuit
crater, which rises from
the tundra in northern
Quebec. An early
prospector mistak-
enly believed that
the almost perfectly
round feature was a
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A satellite image
uses false color to
highlight the lake
at the center of
South Australia’s
Acraman crater.kimberlite pipe where
he might find dia-
monds. Those who
trek out to Pingualuit
today will instead
find the “crystal eye
of Nunavik,” a deep
freshwater lake filled
with extraordinarily
clear water. A different
sort of lake, one that’s
shallow and salty,
marks the center of
the Acraman crater,
located in the Gawler
Ranges of remote, arid
South Australia.EXPLORE MORE
Lowell Observatory
Flagstaff, Arizona
As part of their prep
for the moon landing,
Apollo astronauts
visited this site where
Pluto was discovered
in 1930. Take a look
through the Clark
Refractor telescope,
which has been used
to study moons, plan-
ets, and comets. This
year the Giovale Open
Deck Observatory
debuts. lowell.eduADDITIONAL REPORTING BY KIMBERLEY LOVATOPLACES WE LOVE
SOUTH AUSTRALIA