of moon’s radius
since its formation
not so incredible
Widespread cliff formations
signal reduced lunar radius
By Gwyneth Dickey
The moon has shrunk in the past billion
years, new high-resolution pictures suggest. Evidence comes in the form of cliffs
all over the moon that have formed over
the last million millennia like wrinkles
on a dried-out piece of fruit.
Scientists have studied more than 70
of these cliffs, called lobate scarps, using
Apollo mission images from the 1970s.
The scarps are generally tens of kilome-
Cliffs called lobate scarps form as the
moon’s interior cools and shrinks.
ters long and less than 100 meters high.
Researchers had hypothesized that the
scarps resulted from shrinkage, but
Apollo images did not show whether the
scarps spanned the moon’s entire surface.
Now, images from NASA’s Lunar
Reconnaissance Orbiter reveal 14 new
scarps, providing the first definitive evi-
dence that the scarps occur globally.
Twinkle, twinkle, little fuzzy dot
Astronomers still wonder whether you’re a planet or not
By Ron Cowen
The faint celestial object TMR-1C has
had a checkered past — and now it has a
In 1998, NASA proclaimed that a
picture taken the previous year of TMR-
1C — a fuzzy white dot — with the Hubble
Space Telescope might go down in history
as the first planet beyond the solar system
to be photographed (SN: 6/6/98, p. 357).
Susan Terebey, now at California State
University, Los Angeles, led the discovery
team, which suggested that the object’s
location — at the end of a long, luminous
filament emanating from two newborn
stars — indicated that it was a planet cast
off by those incipient suns.
Skeptical researchers noted that the
apparent association between the object
and the youthful stars might be a chance
alignment. Only a year later, Terebey
herself declared that the body was too
hot to be a planet and could be just an old
background star (SN: 6/26/99, p. 404).
Now two independent studies, both
to appear in an upcoming Astronomy &
Astrophysics, indicate that Terebey may
have written off TMR-1C prematurely.
september 11, 2010 | science news | 11