Sky & Telescope - April 2023 QR - 11

PASACHOFF: JAY PASACHOFF / WILLIAMS COLLEGE; BOULDER-STREWN REGION ON MARS: NASA / JPL
OBITUARY
Jay Pasachoff (1943-2022)
CHAIR OF THE ASTRONOMY Department,
Director of the Hopkins Observatory,
and Field Memorial Professor of
Astronomy at Williams College in Williamstown,
Massachusetts, Jay M. Pasachoff
succumbed to cancer on November
20th. Pasachoff was renowned for
his research on the solar corona as well
as his many published works.
Pasachoff was probably best known
as one of the world's foremost eclipse
chasers. Over six decades he traveled to
see 75 solar eclipses, eventually catching
36 totals, 19 annulars, and 20
partials. According to Bill Kramer and
Andreas Möller's international eclipsechasers
log, Pasachoff ranks #2 by
number of solar eclipses of all types, #1
by number of totals, and #3 by cumulative
time in the Moon's umbra.
After completing his education at
MARS
Ancient Megatsunamis
Tossed Martian Boulders
SCIENTISTS HAVE TRACED the origin
of boulders found near NASA's first
successful Mars landing: The rocks
came from an impact that occurred billions
of years ago in an ancient ocean,
producing a mega-tsunami that carried
them up onto the one-time shore.
On July 20, 1976, Viking 1 landed
in Chryse Planitia, a low-lying circular
plain that might once have contained
an ocean. But rather than seeing signs
of water, Viking 1 found only boulders
with unclear origins.
In 2016, Alexis Rodriguez (Planetary
Science Institute) led
a team that reported
evidence of two megatsunamis,
both occurring
around 3.4 billion
years ago in an ocean
that then covered the
north of the Red Planet.
More recently, Rodriguez's
group modeled
the tsunamis in order
Harvard and doing postdoctoral
research there
and at Caltech, Pasachoff
settled into what would
become a 50-year career at
Williams College. He often
brought students along
on eclipse expeditions,
gathering photometric and
spectroscopic data on the inner corona.
Quite a few of those former students
are now astronomy professors at other
institutions, which delighted Jay.
Pasachoff was prolific in both
research and writing, including textbooks
and popular articles. He was also
active in many professional organizations,
including the International
Astronomical Union (IAU), the American
Association for the Advancement
of Science (AAAS), and the American
Astronomical Society (AAS). He was
elected to leadership positions in most
of those groups and named Fellow of
to understand the impact craters that
could have created them.
On December 1st in Scientific
Reports, the team reports the most likely
suspect for the first of these events: the
110-kilometer (70-mile) Pohl Crater
about 900 km northeast of the Viking
1 landing site. That impact created a
tsunami that carried debris generated in
the post-impact shock wave.
" The marine floors would have been
tossed up, " Rodriguez says, " feeding the
wave with sediments and probably aiding
the development of a catastrophic
debris flow front. "
The megatsunami initially reached a
height of about 500 meters (1,640 feet)
and propagated inland to some 250
meters above sea level,
aided by the low slope
of the terrain. The slope
also slowed the backwash,
keeping most of
the debris on land. The
tsunami from the secNASA's
Viking 1 took
this image of Mars in 1976,
showing strewn boulders of
unknown origin.
Jay Pasachoff at the Jansky
Very Large Array in New Mexico
during a 2012 solar eclipse.
the AAS, AAAS, American
Physical Society, and Royal
Astronomical Society. Jay
and his wife Naomi regularly
welcomed colleagues,
students, and friends into
their home. The IAU named asteroids
for both of them: 5100 Pasachoff and
68109 Naomipasachoff.
Among his many other honors,
Pasachoff received the AAS Education
Prize in 2003 for his textbooks and the
Astronomical Society of the Pacific's
Klumpke-Roberts Award in 2019 for his
astronomy outreach.
I'm sure I won't be alone in raising
a bottle of Corona beer to toast Jay's
memory at the next solar eclipse.
¢RICHARD TRESCH FIENBERG
Read Fienberg's remembrance at
https://is.gd/JayPasachoff.
ond impact later covered Pohl Crater.
While both events happened during
the Late Hesperian, a long-ago epoch
of on-again, off-again seas, their exact
timing is still uncertain.
¢JEFF HECHT
Hear a Martian
Dust Devil
NASA's Perseverance rover has
recorded the sound of a dust
devil passing overhead. " Each
SuperCam microphone recording
lasts only 167 seconds, and
we only perform on average eight
such recordings a month, " says
Naomi Murdoch (University of
Toulouse, France), who led the
study published December 13th
in Nature Communications. " So
we got lucky! " The team estimates
that the vortex was 118 meters
(387 feet) tall and 25 meters wide.
It traveled at a sedate 5 meters
per second (11 mph), though the
winds within the vortex whipped
around at 25 mph on average. Listen
here: https://is.gd/DustDevil.
¢ MONICA YOUNG
sk yand tele scope .o r g * APRIL 2023 11
https://www.is.gd/JayPasachoff https://www.is.gd/DustDevil https://skyandtelescope.org/
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