Sky & Telescope - December 2023 - 6

INSIGHT SELFIE: NASA / JPL-CALTECH; SAD EARTH: DKDESIGNZ / SHUTTERSTOCK
FROM OUR READERS
apart - so far that we couldn't put them
both on our map on pages 14-15, because
it would have necessitated extending the
map eastward by at least 40° longitude.
The impact risk is higher on Mars than it
is on Earth, because our denser atmosphere
shields us better. But still, I'm told it's not a
major concern.
Dusty Mars
Two questions came to mind after
reading Javier Barbuzano's excellent
article " Shake, Rattle, and Roll " (S&T:
Aug. 2023, p. 12) on the Mars Insight
lander. Dust covered the lander's solar
panels, and the mission ended after
four years. Bruce Banerdt, the principal
investigator, said it was like losing a
friend and colleague. Insight was still
doing its job providing valuable data
on the planet's interior structure up
to that point, even though the mission
was only expected to last two years.
What dust-clearing techniques is NASA
working on, since this is a well-documented
problem? Having longer-term
instruments would be a huge benefit in
planning future missions and studying
the planet.
Second, the lander's seismometer
detected two meteorite impacts on
Mars in 2021, and the Mars Reconnaissance
Orbiter found craters up
to 150 meters (500 feet) in diameter.
How does NASA plan to deal with
these risks in future manned missions?
Astrophotography: Why Not?
Tony Puerzer's excellent article " Astrophotography:
Why Bother? " (S&T: Aug.
2023, p. 54) details many important
reasons for pursuing amateur astrophotography.
For me, astrophotography
opens a window to explore the nature
of the celestial objects imaged and the
history of how our knowledge of the
complex and beautiful universe has
developed. Astrophotography enables
me to see things that are not available
6
DECEMBER 2023 * SKY & TELESCOPE
p NASA's Insight lander captured this final selfie
showing the heavy coat of red dust that would
later spell the end of its four-year mission.
Are those risks just added to the list of
" death at your doorstep " in space?
Stephen Keedy
Lebanon, Connecticut
Camille Carlisle replies: Regarding
the dust, I've asked Mars mission
scientists the same thing, but I haven't heard
of any dust-mitigation technology being
developed by NASA for landers and rovers.
Nor do I think we'll see any soon: So far, the
weight and cost associated with installing
such tech (would we have to boot off a
scientific instrument to make space?) has
overridden potential benefits. The philosophy
remains, " let the wind clean it for us. "
To your second question, the danger
from impact is pretty low. A 2013 study estimated
that the average square kilometer of
Martian surface would be hit by something
that could make at least a 4-meter-wide
crater maybe every 600,000 years. The two
impacts we discussed in the article are far
"
if I limit myself to visual observation.
A humbling awe comes with digitally
recording a supernova from a distant
galaxy or capturing a star-forming nebula
in our own galaxy. We are so fortunate
to have readily available tools to
take images of these incredible objects.
What better way to immerse oneself in
the wonders of the universe than a deep
dive into astrophotography?
Jim Case
Chino Hills, California
Arguably Accurate
The article " Shake, Rattle, and Roll " is
marvelously informative and interesting.
However, there is a moment of
unintentionally humorous hyperbole
when the author writes that " Mars is
arguably the most studied planet in the
solar system . . . "
I don't think so!
Joel Marks
Milford, Connecticut
"
Camille Carlisle replies: Ha! That
statement was intentional and
carefully considered. The author and I
discussed it during the fact check - I
literally wrote, " Let's add 'arguably' as a
caveat, since someone may well complain
that we're overlooking Earth. " Certainly,
we have much better seismic data on
Earth, and we've spent a lot of time poking
around our planet's nooks and crannies.
But our satellite maps of Mars are
higher resolution than our maps of Earth's
seafloor, and we know far more about
atmospheric escape at Mars than we do for
any other planet, including Earth.
So, in terms of studying Earth as a planet,
one can make the case that it doesn't
beat out our study of Mars. But, of course,
this is why we said " arguably " - because
we can reasonably disagree.
Keeping It Simple
Great insight from Rod Mollise in his
article " More Better Gooder " (S&T: Aug.
2023, p. 84), which is an invaluable piece
of wisdom. I use the word " insight "
precisely. His comment " I've learned
to see again . . . " - after decades of his
obsession with more " toy " power in his
viewing instrumentation - is the point.
The first deep-sky object I found by
myself in the 1980s with my new Meade
20×80 binoculars remains unforgettable.
Sky & Telescope - December 2023

Table of Contents for the Digital Edition of Sky & Telescope - December 2023
