Sky and Telescope - May 2017 - 6

FROM OUR READERS

H. P. Lovecraft's
Take on Totality
I enjoyed reading Eli Maor's article
about how New Yorkers viewed the
1925 total solar eclipse (S&T: Jan. 2017,
p. 66). This eclipse occurred when horror
and science-ﬁction author H. P. Lovecraft lived in New York City. Lovecraft,
also an amateur astronomer, observed
the eclipse under "marrow-congealing"
conditions and was able to see the
corona. Visit https://is.gd/Lovecraft to
read his letters concerning this eclipse
and the one seen from New England in
August 1932.
Aaron McNeely
New Carlisle, Indiana

The Rocky Road to Mars
I was inspired by David Grinspoon's
history of our preconceptions and realizations concerning the study of Mars
(S&T: Jan. 2017, p. 20). Yes, we've read
or seen the perspectives of H. G. Wells,
Percival Lowell, Carl Sagan, Bruce Mur-

ray, and many others - and what Grinspoon calls their "brilliant mistakes."
But let's continue with both science and
imagination. There are so many of us
with portions of both.

that science cannot describe to us the
true meaning of nature's huge numbers,
immense distances, and eons of time.
We need the artists, musicians, writers,
and poets to do that.

Earl Finkler
Medford, Wisconsin

Ken Coles
Indiana, Pennsylvania

Grinspoon makes telling points about
the difﬁculty of predicting what we will
discover about Mars or anything in the
cosmos. I was present, as a 14-year-old,
in the audience at the 1971 gathering he
describes. My father, an engineering professor at Caltech, knew of my interest in
planetary exploration and got us tickets.
At the time I had only a general idea who
Sagan and Murray were and was not yet
familiar with the science journalism of
moderator Walter Sullivan.
My strongest memory of that evening was the moment Ray Bradbury,
who was no myth to me, stood up
and read a poem. Even today, I tell the
undergraduates in my astronomy classes

Kudos for Deep-Sky Wonders

75, 50 & 25 YEARS AGO by Roger W. Sinnott
1942

1967

1992

6

º May 1942
How Old Are We? "More accurate
measurements, recently made . . .
on sample meteorites, indicate a
considerable range in the helium
content of iron meteorites and a
remarkable constancy of uranium
and thorium, the elements important in age-determinations. The
highest ages derived from the
helium content amount to 6,000
and 7,000 million years. [But an]
extrapolation from data regarding
the 'expanding universe' would
allow only 2,000 million years as
the age of the universe. Evidently
mother nature is skillful in concealing her true age."
Better methods have adjusted
estimates of the ages of meteorites and our solar system to about
4,600 million (4.6 billion) years. But
since 1942 cosmologists have often
revised the intergalactic distance
scale and expansion rate, leading to a sevenfold "aging" of the
universe as a whole.

M A Y 2 0 1 7 * SK Y & TELESCOPE

Although I've mostly given up visual
for imaging, I get a lot of target ideas
from Sue French's observing column
in @SkyandTelescope.
Richard S. Wright Jr.
@AccidentalAstro

FOR THE RECORD

✹ The amount of dirt and stone removed
for the FAST radio telescope was 900,000
cubic meters, not nearly 1 cubic km as the
caption states (S&T: Feb. 2017, p. 29).
✹ The reference star used as an aid to
spotting NGC 1954 (S&T: Feb. 2017, p. 56)
is 8 Lep, not 8 Lac.

º May 1967
What Are Tektites? "For two centuries scientists have been puzzled
by certain small glassy objects, usually rounded, that are found in great
numbers in some geographical
areas, but are virtually absent elsewhere. These tektites are ordinarily
in the size range of gravel. . . . The
term strewnﬁeld is used for a major
area of the earth's surface in which
tektites are found. [There are] four
known strewnfields, each of which
has a different estimated age. . . .
"In color, tektites range from
black through dark brown to bottle
green. . . .
"[Most scientists] agree that tektites are in some way or another the
result of large meteorite impacts.
Some theories maintain that tektites
are lunar material, dislodged by
impacts from the moon's surface;
others state that they are terrestrial
material affected by impact."
Author Darryl Futrell went on to
describe and illustrate the known
varieties in detail. The actual lunar
samples returned a few years

later by Apollo astronauts did not
match tektites in composition. Most
experts now regard tektites as
impact-shocked terrestrial material.
º May 1992
Missing Clusters "A few years ago
R. Sagar and A. K. Pandey collected
all the available age determinations
for star clusters in the Magellanic
Clouds, the Milky Way's two largest satellite galaxies. Surprisingly,
they found no cluster in the Large
Magellanic Cloud (LMC) with an age
between 5 and 15 billion years. . . .
"Is this apparent 10-billion-year
age gap real, or is it due to systematic errors in determining cluster
ages? . . . The strongest argument
actually comes from the Small
Magellanic Cloud (SMC), which
does harbor clusters between 5 and
15 billion years old. . . . The reason
for the long quiescent period in the
LMC remains a complete mystery."
The age gap described here by
Sydney van den Bergh (Dominion
Astrophysical Observatory) remains
an enigma.
https://www.is.gd/Lovecraft
Sky and Telescope - May 2017

Table of Contents for the Digital Edition of Sky and Telescope - May 2017
