Vassar Quarterly - Spring 2018 - 12
"LITTLE BLUE DOTS"
Award-winning astronomer Debra Elmegreen
and spouse discover a new kind of galaxy on the
edge of detectable space.
ebra Elmegreen, Maria Mitchell Professor of Astronomy
at Vassar, and her husband, Bruce, an IBM astronomer,
recently announced the discovery of "Little Blue Dots,"
a kind of galaxy never before seen. Using data and photographs from the Hubble Space Telescope, they detected
what appeared to be tight clusters of rapidly forming stars
dating back to the early stages of the formation of the universe.
"We kept finding these little blue dots," Elmegreen says. Since
these dwarf galaxies were smaller than the galaxies some astronomers have dubbed "blueberries," the Elmegreens decided to call
their discovery "Little Blue Dots."
"Ordinarily, I don't like the cute names that astronomers sometimes call their discoveries," Elmegreen says, "but in this case, that's
exactly what they are. We found 55 of them."
In a paper published in January, the Elmegreens posited that
these Little Blue Dots wind down their rapid star formation "after a
few tens of millions of years" and eventually become the precursors
to globular clusters, common aggregations of stars found in most
The discovery is significant because it adds to the body of knowledge about how galaxies formed and evolved when the universe
was one-fifth to one-half of its current age. (Today it's about
14 billion years old.) galaxies like these must have merged with
larger galaxies like the Milky Way to become part of galaxy halos,
Whatever she chooses to explore next,
Elmegreen says she's certain there are
many new discoveries ahead for her and
many other astronomers. "With the Hubble
going up in 1990 and the much larger James
Webb Space Telescope due to launch in a
year or so, it's an unbelievable time to be an
astronomer," she says.
For her work in the field, Elmegreen was
recently awarded the American Astronomical Society's george Van Biesbroeck
Elmegreen points to
the Little Blue Dots in
an enlargement of a
Frontier Field image
from the Hubble Space