Estimated
deforestation in
Brazil, 2004
7,500
square km
Estimated
deforestation in
Brazil, 2009
Potential predictor of solar storms
Microwave bursts may warn of impending eruption from sun
By sid Perkins
Fluctuating bursts of microwave energy
from the sun could give advance warning
of the huge solar flares known as coronal
mass ejections, new research hints.
During these events, immense clouds
of radiation and charged particles erupt
from the sun’s surface. When these coronal mass ejections, or CMEs, strike and
envelop Earth, they can disrupt radio
communications, overload power grids
and zap Earth-orbiting satellites, said
Pierre Kaufmann, a solar physicist at
Mackenzie Presbyterian University in
São Paulo, Brazil.
While studying the solar emissions
associated with 10 CMEs that occurred
during a period of intense solar activity
in October and November 2003, he and
colleague Rodney V. Souza noticed that
the sun emitted bursts of microwave
energy during or before each one. For
three of the CMEs, the burst coincided
with the flares’ eruptions from the sun’s
surface, Kaufmann reported August 9.
But for the other seven, the microwave
bursts— which fluctuated every few
seconds—preceded the eruption of the
CME by between five and 15 minutes.
forest loss slowing in Brazil
Deforestation has dropped dramatically in Brazil thanks to a variety
of incentives that may provide a
model for other regions as well,
Columbia University geographer
Ruth S. DeFries said August 9.
Besides stepping up enforcement
of strict laws regarding deforestation, Brazil has reduced bank loans
to large agricultural producers,
boosted incentives to increase
agricultural production on lands
already cleared and increased public awareness of deforestation.
The result: Forest losses dropped
from 28,000 square kilometers
in 2004 to about 7,500 square
kilometers in 2009. Policies such
as those implemented in Brazil
in recent years can help preserve
large areas of virgin forest in
nations such as Peru, Suriname
and the Democratic Republic of
the Congo, DeFries suggested.
— Sid Perkins
coronal mass ejec-tions (one launched
by the sun in 2002
shown) may often be
preceded by strong
microwave bursts.
chinchilla poop rain gauge
The size of fecal pellets in ancient
rodent middens can provide clues
about rainfall in times past, paleo-
ecologist Claudio Latorre Hidalgo of
Pontifical Catholic University of Chile
in Santiago reported August 9.
He and colleagues scrutinized
middens left by chinchillas at nine
sites in South America’s Atacama
Desert. The size of the largest
fecal pellets in a midden corre-
lated with rainfall for that site at
the time the midden formed. The
new proxy for rainfall may prove
useful when other sources of
climate clues, such as sediment
cores drilled from lake beds, aren’t
readily available, he noted.
— Sid Perkins
www.sciencenews.org
August 28, 2010 | science news | 13
