WWW.ASTRONOMY.COM 49it does have a stove used to prepare meals. Another wooden struc-
ture serves as a garage for repairing scientific equipment and snow-
mobiles. Sleeping quarters are in mountain tents or in a structure
known as the “Rack Tent,” a spot our camp hosts offered us. After
Fang, these accommodations felt like a five-star hotel.
From the base camp, we proceeded on foot and snowmobile to
explore the ice towers of Erebus. The majority lie near the summit
in a parade of white columns called Ice Tower Ridge. There,
bizarre structures form over vents and fumaroles on the volcano’s
f lanks. Hot gases from Erebus’ depths escape through the ice,
melting some of it into water before the frigid air quickly refreezes
it. Airf low causes the newly formed ices to grow into towers. Some
of the structures are as tall as a five-story building. The frosty edi-
fices take on strange, whimsical shapes, with holes, cracks, and
hollows venting sulfurous vapors. Rounded or spiky crests crown
the towers, which the fierce Antarctic winds sculpt into oddities
that could stand up well in a modern sculpture garden.
Beneath the towers, caves filled with ice crystals and blue light
spread into a network of underground chambers. These can be
dangerous because their roofs are fragile and disguised as f lat
ground above. Evan helped us steer clear of the hazardous terrain
that masked these underground traps.Although we explored several caves near the Lower Erebus Hut,
caverns farther up on Ice Tower Ridge were off-limits because they
contain distinct extremophile colonies. To see these rare microbes,
one must have special permits and wear a sealed protective suit with
air filters so as not to contaminate the fragile ecosystems. We con-
tented ourselves with the study of aboveground wonders, the kinds
of scenes that might greet future explorers on Enceladus or Titan.Peak experience
Christmas Day 2016 offered us a special present: a final hike up
to see the crater of Mount Erebus. To access the caldera’s rim,
our colleagues took us on a snowmobile ride halfway around
the mountain. There, a f lat staging area marks the site of the
now-abandoned Upper Erebus Hut. A small field with two large,
circular wounds is all that remains of this science outpost. These
craters are remnants of lava bombs that landed outside the hut in
the mid-1980s. The incident made a good cautionary tale: It was
time to vacate the small structure in favor of the safety of the more
remote Lower Hut.
From the staging area, the climb to the rim is less than
1,000 feet (330 m). But with little to breathe in the thin polar air
and steep slopes to negotiate, it took us nearly an hour of hiking
to arrive at the summit caldera.
The trek was worth it. Erebus’ crater has precipitously steep
walls encrusted with ice and snow. Rock ledges paint the caldera’s
walls in shades of brown, tan, and gray. Vapors from the center of
the pit billow up, clouds born from the volcano’s active lava lake.
The lake itself is rarely visible because venting gases fill the crater
and obscure the view. Although we could not see the lake, Rosaly
imaged the area with special infrared equipment for future analysis.
The entire crew from the Lower Erebus Hut made the trip.
From our vantage point, we could see a group on the opposite side,
peering into one of the most famous volcanoes in the world. We
had come from diverse backgrounds and homes scattered across
several continents, but in the shadow of Erebus, we stood together,
enjoying a spectacular Antarctic vista. It was a fitting end to an
exotic expedition.Michael Carroll is a science writer and astronomical artist. Rosaly Lopes is
a planetary geologist and volcanologist at NASA’s Jet Propulsion Laboratory.sculpt these towers. ROSALY LOPES AND MICHAEL CARROLL
Ice towers on
Mount Erebus
inspired this
illustration
of Enceladus.
Some evidence
suggests that
ancient tiger-
stripe terrain
may have
migrated north
of the areas
active today.
Here, we see
one of these
long-dead sites
that retains
structures
built during its
heyday. MICHAEL
CARROLLMountaineer Evan Miller’s shadow falls across the acrid mist rising from the
lava lake at the heart of Mount Erebus’ caldera. Sulfur compounds, similar
to those on Jupiter’s moon Io, tint the rocks yellow. MICHAEL CARROLL