WWW.ASTRONOMY.COM 7TWIN
JETS
Hubble snaps
an image
of a bizarre
object.
The Orion B molecular
cloud hides HH111, a
prime example of a rare
celestial phenomenon
generated by protostars
— very young stars still in
the process of coalescing.
Even as protostars gather
material from the accre-
tion disks around them,
they sometimes expel
material from their poles
as well. These jets are
extremely fast — typically
moving at hundreds of
miles per second. When
the jets collide with
clouds of gas and dust
surrounding the baby star,
a Herbig-Haro object like
HH111 is born.
The objects release
plenty of optical light,
but are surrounded
by gas and dust that
subsequently absorb it.
To capture this image
of HH111, the Hubble
Space Telescope used its
Wide Field Camera 3,
which can observe at the
infrared wavelengths,
to reveal the object.
— CAITLYN BUONGIORNOASTEROID MILLENNIAL
In August 2021, the near-
Earth asteroids 2021 PJ
and 2016 AJ193 (above)
became the 1,000th and
1,001st such objects
observed with planetary
radar — which sends out
powerful signals used to
determine asteroid orbits
— since 1968.ATMOSPHERE HALF FULL
Jupiter’s icy moon
Europa has a persistent
atmosphere of water
vapor, according to
an analysis of Hubble
Space Telescope data.
But it exists only in the
hemisphere opposite
its direction of orbital
motion.DEATH BY MERGER
Astronomers have
found evidence of a
never-before-seen type of
supernova that detonated
in 2014. The collision of
a neutron star or black
hole disrupted the star’s
internal nuclear reactions,
causing its core to
violently collapse.HOT
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