Researchers revamp ideas about what’s in the sun | By Alexandra Witze
In the pantheon of cosmic celebrities, the sun is one true superstar. It’s not only the Earth’s prime source of light and heat — it also fuels the greenery
that makes breathing possible, keeps
time by setting the body’s daily rhythms
and spits out charged particles that create the beauty of the aurora borealis.
But for all its roles on life’s stage, the
sun remains something of an inscrutable
star. You might say it’s the Tiger Woods
of the cosmos.
Behind its blazing facade, the sun
turns out to be reluctant to give up its
secrets. Most frustratingly, astronomers
haven’t figured out one of the most basic
facts about Earth’s nearest star: exactly
what it’s made of.
“We really don’t know what the sun’s
composition is,” says Carlos Allende
Prieto, an astronomer at the Instituto
de Astrofisica de Canarias in the Canary
Islands. “It’s a big problem.”
Physicists do know a lot about the sun
and how it works: Hydrogen atoms fuse
in its core, forging helium and heavier
elements and spewing out energy in
the process. But over the past several
years, scientists have dramatically over-
hauled estimates of the sun’s chemical
makeup. In particular, they say there
may be far less of key elements such as
oxygen, carbon and nitrogen than previ-
ously thought. These changes are major
enough to throw into question other
basic assumptions about the sun, such
as ideas about how sound waves travel
through its interior, ringing it like a gong.
