WWW.ASTRONOMY.COM 35Clark telescope for further studies of
nebulae. Before World War I was fin-
ished, he studied spectral lines in aurorae
and found a “permanent aurora.” By this,
he meant that the night sky was not
absolutely dark. He discovered many
new features in the spectrum of the sky,
revealing ionized elements in Earth’s
upper atmosphere. Later, in the mid-’30s,
Slipher extended his analyses of the sky
to the zodiacal light, studying that glow
from dust particles in the plane of the
solar system.
In addition, Slipher led two eclipse
expeditions, in 1918 to Syracuse, Kansas,
and in 1923, to Ensenada, Mexico. He
also made spectral studies of unusual
objects like the Crab Nebula, Hubble’s
Variable Nebula, and the unusual nebula
NGC 6729. He supervised the search for
a new outer solar system planet, bringing
on board Clyde Tombaugh, a young
Kansas farm boy, who would in 1930
find Pluto.
Although Slipher was a cautious
thinker, he adopted some of the more
aggressive and controversial ideas of his
employer, Percival Lowell, throughout
the early part of his career. He did not
question the possibility of life on Mars,
and believed that the cosmos contained
millions of planets that could support
some sort of life.
But Slipher will be remembered for
his discoveries relating to spiral nebulae
and the expanding universe. When he
received the Royal Astronomical
Society’s Gold Medal in 1933, the presi-
dent said: “In a series of studies of the
radial velocities of these island galaxieshe laid the foundation of the great struc-
ture of the expanding universe. ... If cos-
mogonists today have to deal with a
universe that is expanding in fact as well
as in fancy, at a rate which offers them
special difficulties, a great part of the
blame must be borne by our medalist.”
When it comes to the expanding uni-
verse, the rotation of galaxies, the discov-
ery of the interstellar medium, important
studies of aurorae and sky glow, and
other areas, we should not forget the
name V.M. Slipher. Edwin Hubble helped
us define galaxies. His associate Slipher
gave us universal expansion, a concept
that governs the mighty cosmos.David J. Eicher is editor of Astronomy
and the author of 23 books on science and
history.ABOVE: In 1947, V.M.
Slipher (left) poses
with Carl Lampland
in front of the Lowell
Observatory
administration
building.
TOP RIGHT: In 1955,
during the centennial
celebration of Percival
Lowell’s birth, V.M.
Slipher (left) and Stanley
Sykes lay a wreath on
Lowell’s tomb.RIGHT: V.M. Slipher
(right) and Al Wilson
pose in Lowell
Observatory’s reading
room about 1955.