This Month in the History of Astronomy - May
- May 6, 1872 - Willem de Sitter, Dutch astronomer and
mathematician, who worked at the Cape Observatory in South Africa
and later became chair of astronomy at Leiden University for the
last fifteen years of his life.
He's chiefly remembered now for the de Sitter model of the universe
(1917), an early solution to Einstein's equations of general
relativity which is spatially flat, has no matter in it (zero
density), but a positive cosmological constant, so it expands.
Two years before his death he co-authored a paper with Einstein,
creating what's called the Einstein-de Sitter universe (1932), in
an attempt to combine all the observational data then known into
a coherent model for the universe; this universe is also flat, but
contained matter and therefore decelerated.
During WW I, de Sitter provided the only copies of Einstein's papers
on his new theory of relativity (general relativity) to the English
speaking world, via Arthur Eddington in Great Britain, who would be
instrumental in promoting and testing the theory at the May 29, 1919,
total solar eclipse (see below).
- May 15, 1713 - Nicholas Louis de la Caille (or de Lacaille),
French astronomer and mapmaker who demonstrated that the Earth bulged
at the equator. From 1751 to 1753 he mapped the southern skies from
The Cape of Good Hope and established the 14 "modern" constellations
- May 17, 1835 - J. Norman Lockyer, discoverer of the element
helium in 1868, while making visual spectroscopic studies of the sun
(helios), when he attributed unknown absorption lines to the new
element, not located on earth until 1891. It's the second simplest
and most abundant element in the universe after hydrogen -- though
rare on earth because here it results from the alpha decay of
Sir Lockyer is also known as the Father of Archeoastronomy: he was
among the first to propose that Stonehenge was an astronomical
observatory and that the Egyptian pyramids and great medieval
Christian cathedrals were built along important astronomical
- May 22, 1920 - Tommy Gold, iconoclastic and outspoken
Austrian-born British cosmologist who never got a Ph.D.
Besides his work with Fred Hoyle and Hermann Bondi on the steady
state theory, Gold, after moving to the U.S. at age 36, is probably
most famous now for raising the alarming possibility that the first
lunar lander might sink into a deep, quicksand-like layer of fine
lunar dust and immediately be lost.
In 1959 he switched from Harvard to Cornell, and subsequently
hired both Carl Sagan (who'd been denied tenure at Harvard) and
Frank Drake, as well as being instrumental in the building of the
Arecibo radio telescope.
Later he would propose what's known as the deep hot biosphere,
anaerobic bacteria and other similarly simple lifeforms living
deep down in the earth's crust in a hitherto unknown ecosystem;
when a Swedish drilling team stopped after going a couple of
kilometers down without finding anything his quip was that they
didn't go deep enough.
- May 25, 1865 - Pieter Zeeman, Dutch physicist who discovered
the splitting of spectral lines by strong magnetic fields, an effect
now named after him, though it was first predicted by his mentor Hendrik
Lorentz, with whom he shared the 1902 Nobel Prize in Physics, only the
second time it had ever been awarded. George Hale observed the Zeeman
effect in sunspots in 1908, leading to the recognition that they are
dark because magnetic fields are acting to impede motion of hot material
into these regions, "bottling up" gas which cools by radiating away
some of its initial heat content. Zeeman also helped discover the
isotope of argon with mass number 38.
- May 26, 1882 - Kenneth Mees (often C.E. Kenneth Mees,
for Charles Edward), pioneering British photographic scientist who
developed the first emulsions for astronomical use, as well as some
of the first sensitizers making films respond to infrared light out
to ~13,000Å (1933).
After getting his doctorate in photographic theory at the
University of London (1906) working under Chemistry Nobel Laureate
William Ramsay, Mees
went to work for Wratten and Wainwright, Ltd., assisting Frederick
Wratten in developing some of the first panchromatic (red sensitive)
photographic plates. In 1912, Eastman Kodak bought Wratten &
Wainwright chiefly because George Eastman wanted to acquire Kenneth
Mees, bringing him to Rochester, NY, creating the Kodak Research
Laboratories, and making him its first director. Later he would
be VP in charge of Research and Development for Kodak until his
retirement in 1955.
Mees ran the first ever school for aerial photography, during
World War I. Eventually elected to the National Academy of
Sciences (1950 - after he finally became a US citizen), Mees
authored over 100 scientific papers and over-saw the development
of such famous color films as Kodachrome (1935, after non-wandering
dyes were discovered), Ektachrome (1940, using "color couplers"
which form the dyes from developer reaction products), and Kodacolor
His continued and dedicated support of ever better photographic
emulsions for astronomical use was vital for much of astronomy
until the switch-over to solid state, electronic detectors some
decades after his death in 1960. One of the key insights Mees
helped foster was the realization that speed was not necessarily
the central issue for astronomical applications so much as
minimizing what's called reciprocity failure -- the tendency
for emulsions to behave like leaking buckets when the light
levels are very low and the exposures very long. That, as well
as the fact that slower fine-grained emulsions might out-perform
in detecting the faintest objects since film grain acts as a
- May 28, 1930 - Frank Drake, American radio astronomer
and SETI (Search for ExtraTerrestrial
Intelligence) pioneer, who developed the famed equation
named after him shortly after the completion of Project Ozma
(1960), the first search (of two stars: τ Ceti and ε
Eridani) for artificially generated radio signals.
- May 31, 1912 - Martin Schwarzschild, German-born American
astrophysicist. The son of also famous astrophysicist Karl
Schwarzschild (see Oct 9), Martin
left Germany in 1936 and spent most of his post-WW II career at
Princeton working in a multitude of areas relating to stellar
structure and stellar evolution. His 1958 book on the subject
was the standard text for the next 20+ years. After retirement
he also contributed to the field of galaxy dynamics, building
theoretical models of triaxial galaxies.
Discoveries and other firsts
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