Galactic colonization is the concept that humans, or any
intelligence, can spread their individuals throughout the universe by
establishing “colonies” in outer space and on various celestial
Colonization, much as it was for the European colonizers of centuries
ago, would be partly for survival , partly for curiosity and partly for
The sun has ~2 billion years
before it uses up its lifespan. This
will not be a survivable situation
for life on Earth whatsoever.
 There are over 530,000 known
asteroids and possibly trillions of
comets in our solar system
alone. These have devastated
Earth before.
 The Milky Way is ~4 billion years
from colliding with the
Andromeda galaxy.
 The galaxy is rich in natural
resources that are rare or not
found on Earth. These can be
mined and put to use on Earth
and beyond. The moon, for
example, has a relative
abundance of Helium-3, which
is rare on Earth, that could be
used in fusion reactors to power
the entire globe for centuries.
“for example, the smallest Earth-crossing asteroid 3554
Amun (see orbit) is a mile-wide (2,000-meter) lump of iron,
nickel, cobalt, platinum, and other metals; it contains 30
times as much metal as Humans have mined throughout
history, although it is only the smallest of dozens of known
metallic asteroids and worth perhaps US$ 20 trillion if
mined slowly to meet demand at 2001 market prices”
Space travel isn’t entirely
practical. Current costs
for each kilogram
launched into space
range from $4,000 to
$40,000. To build
infrastructure to mine
and colonize
extraterrestrial bodies
would take an
unprecedented initial
 Some argue that
humans should not
export their wars and
waste to other places in
the galaxy.
Most of the expense of space
travel comes from building,
maintaining, and launching
complex launch vehicles from
the Earth’s surface. Each
space shuttle orbiter cost
~$1.7 billion to build; each
mission cost an average of
$450 million.
Earth based launch vehicles
use most of their weight on
fuel. The Space Shuttle
weighed ~4.5 million pounds
at liftoff. ~4.2 million pounds of
this weight was from fuel, fuel
tanks, and boosters.
The further a mission goes, the
more fuel and money it takes
to launch from earth. The
shuttle flew at a relatively low
The answer to cost and fuel
problems is to assemble
and fuel vehicles in space.
Large vehicles can be
assembled piece by piece
in space, fuelled, and sent
outward to other planets,
comets, and asteroids.
Once infrastructure is built
up, these vehicles can
even be formed from
elements mined in space,
avoiding escaping Earth’s
atmosphere and gravity
The nearest star to the
Earth (other than the sun) is
Proxima Centauri. It is 4.5
light years away. The
fastest proven technology
could take a spacecraft
there is ~19,000 years.
Nuclear pulse drives,
though purely theoretical,
would still take ~85 years to
transport humans to
Proxima Centauri.
Objects at the most
optimistic speeds would
face serious risk of hitting
micrometeoroids. They
would also need a way to
The proposed Alcubierre drive
would greatly diminish time
required for interstellar travel,
allowing for faster than light
travel within the constraints of
Einstein’s equation.
An Alcubierre drive would
contract space in front of it and
expand space behind it, thus
travelling faster than light without
exceeding the speed of light in
its frame of reference.
By simply “bending the road,”
we can reach destinations faster
without increasing our speed.
This concept works in theory, but
needs better technology to be
applied to reality.
Long term space travel has a negative
effect on health.
Muscle atrophy, bone density loss, and
macular degeneration are all linked to
long space voyages.
Psychological effects also exist. Space
travel has always been, and will likely
continue to be, done by isolated
individuals or small groups. The most
people ever in space at one time was
thirteen. This could create adverse
psychological reactions.
No emergencies can be immediately
treated, even in the relatively close
orbit that the ISS occupies. Medical
care is entirely dependent on the crew.
Radiation is also incredibly high beyond
low-Earth orbit.
A round trip to Mars would, using
current technology, take eighteen
months. This is far longer than anyone
has ever stayed in space.
Research on adverse
health effects is ongoing
onboard the ISS.
Centrifugal force can
replicate gravity. A
habitable wheel structure
spinning at sufficient speed
would simulate gravity for
its inhabitants. This would
negate almost every
negative heath effect of
space travel.
Radiation can be negated
with adequate shielding.
Robots are increasingly
able to do almost anything
a human can. Not only
that, but artificial
intelligence can provide
companionship in isolation.
If we can reach other planets and
establish enough infrastructure,
theorists suggest that we could mold
or “terraform” these worlds to be
more like our own.
 Mars, Venus, Europa, and even the
moon are all candidates for
 Terraforming would take centuries at
least, and would consist of slowly
changing the atmospheres of
celestial bodies to resemble our own.
 This would eliminate the need for
spacesuits or contained
environments on the planets that
undergo it.
If extra-terrestrial civilizations exist
and have advanced far enough,
then it is entirely likely they are
already colonizing and may
have been doing so for millennia
or more.
They may have already
executed their own versions of
terraforming throughout the
One day, such colonization
could lead to contact… or
We must assume that any other
colonizers face many of the
same challenges as us.
We simply don’t know for sure
People have only been in space for 51 years. We can only assume
that we are just beginning to realize the possibilities of spaceflight.
There is many benefits to reap from large-scale colonization, but it
would require an expensive global effort unlike anything humans
have ever done.
If there are other civilizations out there, they may be in the act of
colonizing, and this could one day lead us to interact with them.
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