Astronomers have glimpsed what may be the farthest galaxy
we've ever seen, providing a picture of a baby galaxy born soon after the beginning
of the universe.
Images taken with the Hubble Space Telescope have revealed the
galaxy at almost 13 billion light-years away, making it the strongest candidate
for the most distant galaxy ever seen, said European Southern Observatory
astronomer Piero Rosati, who helped make the discovery.
Since the galaxy is so far away, its light took ages to
reach us, so what we see now is a snapshot of how this galaxy looked 13 billion
years ago. At that
point in time, the galaxy would have been newly formed, so the new
observations provide a baby picture.
"We certainly were surprised to find such a bright young
galaxy 13 billion years in the past," said astronomer Garth Illingworth of
the University of California, Santa Cruz, a member of the research team. "This
is the most detailed look to date at an object so far back in time."
The young
galaxy, called A1689-zD1, was born about 700 million years after the Big
Bang that scientists think created the universe. For most of its early life,
the universe languished in "dark ages" when matter in the expanding
universe cooled and formed clouds of hydrogen. Eventually matter began to clump
into stars and galaxies that radiated light, heating up the universe and
clearing the fog.
Scientists think this newly discovered galaxy may have been
one of the first to form and help end the dark ages.
"This galaxy presumably is one of the many galaxies
that helped end the dark ages," said astronomer Larry Bradley of Johns
Hopkins University in Baltimore, leader of the research team. "Astronomers
are fairly certain that high-energy objects such as quasars did not provide
enough energy to end the dark ages of the universe. But many young star-forming
galaxies may have produced enough energy to end it."
The discovery was made possible by a natural
magnifying glass — the galaxy cluster Abell 1689, which lies between us and
the distant galaxy. Abell 1689's gravity is so strong it bends light that
passes near it, acting like a giant zoom lens that magnifies what we see.
"This galaxy lies near the region where the galaxy
cluster produces the highest magnification," Rosati said, "which was
essential to bring this galaxy within reach of Hubble and Spitzer."
The discovery, announced today, will be detailed in the Astrophysical
Journal.
advertisement
