BRAIN DAMAGE
A study of five male cosmonauts who
spent an average of 169 days aboard the
International Space Station found long-
duration spaceflights lead to elevated
levels of three biomarkers associated
with brain damage: NFL, GFAP, and
amyloid beta protein Aβ40.LUNAR LOOT
In December 2020, China’s Chang’e 5
mission returned lunar samples to Earth
for the first time in 45 years. Analyses
show that lava was likely still flowing on
the lunar surface less than 2 billion
years ago, raising questions about how
the Moon retained its heat for so long.SUPER ERUPTIONS
Mars’ northern Arabia Terra region likely
experienced thousands of massive
volcanic eruptions within a roughly
500-million-year-long period some
4 billion years ago, according to recently
analyzed images from NASA’s Mars
Reconnaissance Orbiter.WHO’S CALLING?
A strange radio signal from the direction
of our galaxy’s core has astronomers
pondering the existence of a new type
of stellar object. The mysterious radio
waves are highly polarized and the
direction of their polarization rotates with
time. Additionally, their source varies in
brightness by a factor of 100, flickering
on and off seemingly at random.LUCY’S LATCH
After launching Oct. 16, 2021, on a
mission to explore eight asteroids,
NASA’s Lucy spacecraft deployed its two
expansive solar arrays. However, at the
time of this writing, one of the circular
arrays has failed to fully latch. For now,
NASA says Lucy is not in danger and will
continue to operate normally.HONDA ROCKET
Japanese carmaker Honda unveiled its
plan to develop and test launch a
partially reusable rocket by 2030.
Though details are scarce, the rocket
will reportedly use liquid propellant to
send small satellites (less than 1 ton)
into low Earth orbit. — JAKE PARKSQUICK
TAKE SWWW.ASTRONOMY.COM 9AS A SUN-LIKE STAR AGES, it
puffs up and blows away its outer
atmosphere, even as nuclear fusion in
the core putters out as its hydrogen
fuel disappears. Eventually, a remnant
composed of mainly carbon and
oxygen — called a white dwarf — is
left behind. Like a smoldering ember,
this remnant glows brightly with
leftover heat at first, then slowly cools
and dims.
Astronomers believed this cooling
was so reliable that they have long
used an established relationship based
on a white dwarf ’s temperature to
determine its age. But now, Hubble
Space Telescope observations are
painting a slightly different picture.
Researchers looking at aging white
dwarfs within two globular clusters,
M3 and M13, discovered that in M13,
some 70 percent of white dwarfs aren’t
passively cooling. Instead they are
still burning hydrogen — not in their
core, but on their surface. It appears
that somehow, these stars held onto
some of their hydrogen atmosphere
instead of blowing it completely away.
This is at odds with the current pic-
ture of stellar evolution, the research-
ers say. And because astronomers
calculate the age of a white dwarf from
its temperature, the fact that some
continue burning hydrogen envelopes
could throw that estimate off because
they are hotter — and thus appear
younger than they actually are.
The team isn’t sure how or why
some of M13’s white dwarfs retained a
thin envelope of hydrogen to burn in
the first place. What’s more, no white
dwarfs in M3 show this odd behavior.
But M3 and M13 have different
populations of stars, meaning their
resulting white dwarfs should also
be different. Now, the team wants to
study clusters more like M13 to see
whether their white dwarfs are still
burning hydrogen — and begin delv-
ing more deeply into what this means
for how we measure white dwarf ages
throughout the galaxy. — A.K.Some white dwarfs can
look young again
FOUNTAIN OF YOUTH. New Hubble observations of the globular cluster M13 show some of its
white dwarfs are still burning hydrogen on their surface, making them appear younger than
expected. NASA, ESA, AND THE HUBBLE HERITAGE TEAM (STSCI/AURA); ACKNOWLEDGMENT: C. BAILYN (YALE UNIVERSITY), W. LEWIN
(MASSACHUSETTS INSTITUTE OF TECHNOLOGY), A. SARAJEDINI (UNIVERSITY OF FLORIDA), AND W. VAN ALTENA (YALE UNIVERSITY)mobilism.org