M YSTERY SOLVED
Dusty pseudomoons detected near Earth
Meet the Kordylewski dust clouds, shimmering pseudomoons orbiting Earth.
Hungarian astronomers and physicists say they spotted light scattered from one of the
clouds, providing evidence after nearly 60 years of controversy that the clouds really exist.
The twin dust clouds gather at two points in space where Earth’s gravity cancels out
the moon’s gravity. That gravitational stability makes these spots, called Lagrange points,
good places to park spacecraft — and trap interplanetary debris.
No one had definitively seen the dust
clouds since Polish astronomer Kazimierz
Kordylewski reported the first sighting in
1961. Some think the sun’s stronger grav-
ity sweeps the two spots clear periodically,
which could explain the “now you see it,
now you don’t” results of past searches.
Judit Slíz-Balogh, András Barta and
Gábor Horváth, all of Eötvös Loránd
University in Budapest, searched through
a special telescope filter that detects light
polarized from bouncing off dust grains.
After months, the group spotted a telltale
shimmer around one of the gravitational
dead zones, the team writes in a paper to
appear in the Jan. 1 Monthly Notices of the
Royal Astronomical Society. The physics of
Lagrange points suggests that, if one cloud
exists, the other does, too. — Lisa Grossman
50 YEARS AGO
threaten a theory
Locust: The Opera finds a novel way to
doom a soprano: species extinction.
The libretto — written by Jeff Lockwood,
an entomologist at the University of
Wyoming in Laramie — features a scientist,
a rancher and a dead insect. The scientist
UPDATE: What comes
naturally to the nine-banded
armadillo, the species that
baffled scientists 50 years
ago, is rare in other mammals.
many offspring from a single
fertilized egg, does result in
genetically identical armadillo
pups. But scientists now know
that other factors also stir
the developmental pot. For
example, epigenetic marks, the
chemical tags that control a
gene’s activity level, can make
identicals look very different.
Though genetically fascinating, armadillos never topped
rodents as research subjects — possibly due to their
fresh insect diet and long time
between litters. Scientists do
use the tanklike creatures to
study leprosy, a disease the
animals can pick up and pass on
to humans (SN: 5/21/11, p. 9).
Excerpt from the
November 30, 1968
issue of Science News
Soprano Cristin Colvin
of Denver performs in
September as the ghost
of the extinct locust.
Using a special telescope filter, astronomers
spotted evidence of one of Earth’s elusive dust
satellites. The dust cloud (brighter red) is in a
gravitational dead zone known as L5.
THE SCIENCE LIFE
Tragic soprano: How a locust
extinction inspired an opera Armadillos come in fours, quadruplet offspring from a
single egg, and are endowed
with identical genes. Yet, the
quadruplets are often not
identical, a fact that calls into
question the assumption that
genes encased in the nucleus
of the cell are the sole deter-
minants of heredity.
tenor agonizes over why the Rocky
Mountain locust went extinct at the dawn
of the 20th century. He comes up with
hypotheses, three of which unravel to
music and frustration.
The project hatched in 2014. “Jeff got in