This
galaxy is so large, so fully-formed, astronomers say it shouldn't exist
at all. It's called a "grand-design" spiral galaxy, and unlike most
galaxies of its kind, this one is old. Like, really, really
old. According to a new study conducted by researchers using NASA's
Hubble Telescope, it dates back roughly 10.7-billion years — and that
makes it the most ancient spiral galaxy we've ever discovered.
"The vast majority of old galaxies look like train wrecks," said UCLA astrophysicist Alice Shapley in a press release. "Our first thought was, why is this one so different, and so beautiful?"
"The vast majority of old galaxies look like train wrecks," said UCLA astrophysicist Alice Shapley in a press release. "Our first thought was, why is this one so different, and so beautiful?"
Shapley is co-author of the paper describing the discovery, which is published in the latest issue of Nature.
She and her colleagues had been using Hubble to investigate some of our
Universe's most distant cosmic entities, but the discovery of BX442 —
which is what they've dubbed the newfound galaxy — came as a huge
surprise.
"The fact
that this galaxy exists is astounding," said University of Toronto's
David Law, lead author of the study. "Current wisdom holds that such
‘grand-design' spiral galaxies simply didn't exist at such an early time
in the history of the universe."
The
hallmark of a grand design galaxy is its well-formed spiral arms, but
getting into this conformation takes time. When astronomers look at most
galaxies as they appeared billions and billions of years ago, they look
clumpy and irregular. A 10.7-billion-year-old entity, BX442 came into
existence a mere 3-billion years after the Big Bang. That's not a lot of
time on a cosmic time scale, and yet BX442 looks surprisingly put
together. So much so, in fact, that astronomers didn't believe it at
first, chalking their unusual observation up to the accidental alignment
of two separate galaxies. But further investigations, conducted at the
W.M. Keck Observatory in Hawaii, revealed BX442 to be the real thing.