WWW.ASTRONOMY.COM 21
erupting from Jupiter’s moon
Europa. The plumes likely
represent material from an
underground ocean venting
through the moon’s icy crust.
Hubble played a key role
in the success of NASA’s New
Horizons’ mission to Pluto.
Between 2005 and 2012, the
orbiting observatory discov-
ered four new targets for New
Horizons: the small moons
Hydra, Nix, Kerberos, and
Styx. But, more importantly,
observations made over several
years mapped light and dark
regions on the dwarf planet’s
surface. The brightest of these
areas so intrigued New
Horizons scientists that they
targeted the f lyby so it would
be front and center at closest
approach in July 2015. That’s
how we learned so much about
the heart-shaped, nitrogen-
ice glacier now known as
Tombaugh Regio. Hubble also
discovered the Kuiper Belt
object 2014 MU 69 , since named
Arrokoth, that New Horizons
flew past January 1, 2019.
Milky Way treasures
Beyond the solar system,
Hubble opened a new window
into star birth and star death.
Raised above Earth’s obscur-
ing atmosphere, the space
telescope collects not only vis-
ible light but also ultraviolet
and infrared radiation (light
with wavelengths slightly
shorter and longer, respec-
tively, than what we can see).
The extra information lets sci-
entists probe deeper into the
thick clouds of gas and dust
that harbor young stars.
This dark pillar of cold gas and dust
in the Eagle Nebula (M16) towers some
9.5 light-years high, roughly twice the
distance between the Sun and the next
nearest star. The pillar shrouds recently
formed stars that have yet to break out
from their natal cocoons. NASA/ESA/THE
HUBBLE HERITAGE TEAM (STSCI/AURA)