Given that they’ve been around when our universe was still a
few billion years old, are ancient globular star clusters the most likely part
of our Milky Way galaxy to harbor advanced intelligent extraterrestrial life?
By: Ringo Bones
Even though the hypothesis has probably been worked out by a
few science fiction authors during the last two centuries, it was in a recent
press conference during the annual meeting of the American Astronomical Society
back in January 6, 2016 that Dr. Rosanne DiStefano of the Harvard-Smithsonian
Center for Astrophysics presented her team’s latest research findings
indicating that we may one day find intelligent space-faring civilizations
occupying star clusters at the edges of our own Milky Way galaxy. According to
DiStefano, lead author of the study published from a joint collaboration
between the Smithsonian Astrophysical Observatory and the Harvard College
Observatory states that: “A globular cluster might be the first place in which
intelligent life is identified in our galaxy.”
These ancient globular star clusters are spherical in shape
and can contain anywhere from hundreds of thousands to millions of individual
stars. In fact, the oldest stars in the Milky Way galaxy can be found in these
areas with a ripe old age of about 10-billion years old. By way of comparison,
current data shows that the age of our universe is about 13.8-billion years and
scientists believe that some stars in these ancient globular star clusters may
have been already around since the birth of our galaxy. The data that
determined the age of these ancient globular star clusters have previously
played an essential role in helping astronomers pinpoint the center of the
Milky Way and aid in determining the exact age of the universe.
The main factor that determines the possibility of carbon-based
Earth-like life-forms occurring in a typical star system is its Goldilocks or
habitable zone. This refers to a “just right” distance between a planet and its
parent star which directly affects the average temperature and the planet’s
ability to allow water in its liquid state to exist. Brighter more energetically
burning stars produce a larger potential habitable zone than their smaller,
fainter counterparts but brighter, larger, more energetically burning stars
have a much shorter lifespan and the largest of them seldom last for more than
150-million years.
Habitable planets that could exist in these ancient globular
star clusters would have to be huddled near dim red dwarf stars and this is
critical because smaller orbits help protect these planets from the violent
forces found in such a crowded galactic neighborhood – forces that could
eventually push a small world out into cold interstellar space. DiStefano
claims that once these planets do form, they can survive for long periods of
time, even longer than the current age of the universe.
Some of these globular star clusters are packed to the brim
and astronomers have estimated that some contain up to a million stars that span
a combined distance of up to 100 light-years. To give you an idea of how dense
that is, our Sun’s nearest neighboring star is close to 4 light-years away.
The main idea drawn by this research includes the high
probability of the formation of potentially habitable worlds in a globular
cluster due to the sheer volume of stars and that these worlds could survive
for billions of years. This is important because complex life takes time to
evolve and to develop the kind of intelligence needed to build and maintain a
civilization – especially a space-faring one.
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