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The Possibility of Life in Our Galaxy

by Darin Beaudreau

Life is all around us. In the short time that man has existed, we have discovered thousands of

species of plant, animal, and insect life, and we continue to discover more all of the time. But ever

since humankind has first looked up at the night sky, they have wondered; are we alone? It was only

recently that we have developed the technology to begin searching for an answer. But if we have

discovered so many terrestrial species on Earth, and our galaxy is one of countless others, all full of

billions of stars, how could we possibly be alone?

Until recently, we had no idea just how incredibly massive the universe is, and even now, it's

still hard to imagine something so infinitely broad. It is highly unlikely that the human race will survive

long enough to explore our own galaxy, let alone others, so trying to find life on a universal scale will

likely not be as productive as trying to find life in our own galaxy. So just how big is our galaxy,

exactly?

The Milky Way galaxy is a spiral galaxy containing an estimated 200 billion stars. The actual

dimensions of the galaxy are estimated to be about 100,000 light years in diameter and 1,000 light

years thick.1

To put that into perspective, one light year is about 9,460,528,400,000 kilometers. Our

galaxy's diameter is 100,000 times that!2

Earth is the only place we can say for certain that life exists, but to think that we're the only

example of life in the universe is preposterous. Centuries ago, people believed in a Geocentric model

(that the Earth was the center of the universe.) It wasn't until Galileo Galilei and Johannes Kepler came

1 http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980317b.html

2 http://tinyurl.com/coj889o (Link shortened. Leads to Google.)


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along that sufficient data was brought forth to prove the Heliocentric model (Sun-centered.)3

Our

knowledge of the structure of the universe changes over time. Now that we know how insignificant our

solar system is compared to the universe as a whole, we can more easily imagine the possibility of

extraterrestrial life.

So in a galaxy as vast as ours, where can we find life? Let's assume that we are only searching

for intelligent life. When humans think of extraterrestrial life, they commonly associate it with the little

green men you would see in old science fiction movies. But to think that all intelligent life is humanoid

seems almost narcissistic. So what should we be searching for?

In our search for extraterrestrial life, we have commonly searched for Earth-like planets, or

planets with water. We search for planets with water because we believe that water is necessary for life,

but why? If we are to believe that life can only survive in an environment with water, then that would

severely reduce the possibility of life anywhere. How do we know that there aren't space-dwelling life

forms who exist as gases? Or life forms who exist as energy? Is it possible that life could exist in our

own solar system and we simply haven't noticed it because we weren't looking for it?

It is commonly believed that life does not exist in our solar system because no other planet in

our solar system has suitable conditions for life... at least, life like us. Mercury, for example, is

extremely close to the Sun. If humans were to go to Mercury unprotected, we would die immediately

due to the extreme heat and radiation from the Sun. But what if there are life forms that need that

radiation to survive? Or life forms that can only survive in environments with extremely high

temperatures, such as that of Mercury.

Those kinds of life forms are called extremophiles, which are life forms that thrive in extreme

conditions. We don't have to imagine the possibility of such life forms, because we have some of them

3 Astronomy Today Volume I: The Solar System Section 2.3 Pages 37-41


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right here on Earth. One such life form, Thermus Acquaticus, is a thermophile (a life form that can

survive and thrive in extreme heat.) This also presents another interesting question; are extreme

conditions for humans considered normal to life forms in other parts of the galaxy?

In the TV series Star Trek, the various crews often encountered incorporeal life forms, such as

the electromagnetic life form encountered in a nebula in the episode of Voyager entitled The Haunting

of Deck Twelve.4

If we are to imagine that this is possible, and not just science fiction, then life could

probably exist just about anywhere.

When you break down human life to its basic components, our intelligence and sentience comes

from electrical impulses in our brain. Our brains form synapses to store information, and the electrical

impulses in our brain are carried throughout our body to regulate our biological functions. So if we

imagine a life form that has no body, and exists as a form of energy, such as the aforementioned

electromagnetic life form, then perhaps it achieves intelligence through the same means; through a

series of electrical impulses. With this in mind, then we must believe that life can exist in a variety of

ways, not just biological. Perhaps the reason we search for conditions in which biological life can exist

in is because we do not yet have any way of determining what other life forms would need to survive.

And even if we did, how would we study these other forms of life if we cannot make direct

observations of it?

We search for life similar to ours because it would be more easily identified. As mentioned

before, if we do not yet have the means to identify life forms we are not familiar with, then we should

stick to what IS familiar until we have the means to find other forms of life. However, this significantly

decreases our chances of finding life, because what are the chances that we will find another species

that is just like us? The chances are pretty slim.

4 http://en.memory-alpha.org/wiki/Class_J_nebula_lifeform


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Despite the odds, in recent years, we have already discovered some Earth-like planets. By

Earth-like, I mean terrestrial, rocky planets with similar conditions to Earth. One such planet, Gliese

581d, which was discovered in 2007, was initially thought to be too far from its host star and too cold

to support an ocean. However, recent evidence suggests that this planet is just outside the habitable

zone (by habitable zone, I am referring to the distance from its star at which life could survive) in its

solar system, and could very well have oceans on it. Gliese 581d is 20.5 light years from Earth, so it is

unlikely we will make contact with any life there if there is any because of how long it would take to

reach with our current technology.5

So where can we find an Earth-like planet closer to home?

Two of our closest neighboring star systems are the Alpha Centauri system and the Epsilon

Eridani system. Even being the closest solar system to us, Alpha Centauri is still 4.35 light years away.

Epsilon Eridani is even further away at 10.5 light years away.6

So how long would it take us to reach

Epsilon Eridani and study it to determine if it hosts life?

According to NASA, a space shuttle, when it separates from its external tank, travels at a

velocity of 28,067 kilometers per hour.7Due to Newtons First Law of Motion

8, if no force,

gravitational or otherwise, was to act upon the shuttle and it could continue to Epsilon Eridani

uninhibited, it would still take approximately 403,745.07 years to reach the system! The total distance

to Epsilon Eridani, in kilometers, is 99,335,548,200,000 (the distance of a light year, 9.4605284 1012

,

multiplied by 10.5.) So how are we supposed to eventually visit these distant neighbors of ours?

Perhaps they have already visited us?

Several futuristic ideas for how to travel amongst the stars have been suggested over the years,

including the Warp Drive in the Star Trek series. However, it has been suggested that warp drive as it is

5 http://news.nationalgeographic.com/news/2009/04/090421-most-earthlike-planet.html6 http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20081027.html7 http://spaceflight.nasa.gov/shuttle/reference/basics/8 http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html


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described in Star Trek would be impossible to achieve because of the law of special relativity, which

state that nothing can travel faster than the speed of light. In an article on AstroEngine, Ian ONeill

suggested that although light speed is a physical limit on how fast we can move through space-time,

there is no limit on how fast space-time can move if it is warped. This gives us a theoretically possible

means of travelling between the stars.9

Stephen Hawking once said that given the size of the universe, it is very unlikely that Earth is

the only place where life has evolved, but he also believed that we should not make contact with them,

comparing what would happen to what happened to the Native Americans after Christopher Columbus

discovered America.10

But there are those in the scientific community who believe that extraterrestrial

life may have already visited us.

Many people believe that our ancestors couldnt possibly have constructed something like

Stonehenge because the stones are too massive for people to have moved without the help of

technology, and that Stonehenge must be the work of extraterrestrials. If extraterrestrials HAVE visited

us in the past, then where are they now? Why would they choose not to remain in contact with us? In

the television series Star Trek, the Federations prime directive was not to interfere with developing

cultures.11

Assuming extraterrestrials had a similar directive, they would already have violated it by

making contact in the past, unless it was an accident; so what reason would they have not to remain in

contact?

There is little factual or credible evidence to support the idea that extraterrestrials have visited

us in humanitys history, but what is the chance that there are other technologically advanced

civilizations in our galaxy? There is an equation, the Drake Equation, which can be used to estimate the

number of technologically advanced civilizations that might inhabit the galaxy, or to a larger scale, the

9 http://www.astroengine.com/2008/07/could-warp-drive-become-a-reality/10 http://www.telegraph.co.uk/science/space/7631252/Stephen-Hawking-alien-life-is-out-there-scientist-warns.html11 http://en.memory-alpha.org/wiki/Prime_directive


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universe. The equation isN = R* fp ne fl fi fc L.12

The equations variables represent the

conditions of planets observed, such as habitability, how many stars have planetary systems, and the

rate of formation for stars suitable for the development of intelligent life.

Then, there is the Fermi Paradox, which basically states If there is extraterrestrial life out there,

where are they?.13

Perhaps they dont see any benefit in contacting us, due to our relatively primitive

technology. The Fermi Paradox also raises another interesting possibility. What if there arent any

extraterrestrial species with technology advanced enough to travel through space?

A Russian astrophysicist named Nicolai Kardashev theorized that advanced civilizations would

be categorized into three types, based on their energy consumption. A Type I civilization would have

harnessed the energy output of an entire planet. A Type II civilization would have generated the energy

output of a star, and would generate about 10 billion times the energy of a Type I civilization. A Type

III civilization would have harnessed the full energy output of a galaxy, producing about 10 billion

times the energy of a Type II civilization. According to Dr. Michio Kaku, humanity is, by contrast, a

Type 0 civilization, as we have not yet harnessed the energy of our planet.14

He also speculates that to

travel at the speed of light, a civilization would have to be a highly advanced Type II, or even Type III

civilization. So if we are to believe that technologically advanced civilizations are few and far between,

let alone civilizations above a Type II, it is possible that a civilization advanced enough to travel the

stars is simply too far away to reach us within their lifetimes.

It may be several hundred, or even thousands of years before we finally develop the technology

to travel deep enough into space to discover an extraterrestrial civilization; but humans have always

been, and will always be fascinated by the stars. As long as we never give up on the idea that

extraterrestrial life exists, I have no doubt that we will someday make first contact with an

12 http://www.seti.org/drakeequation13 http://www.seti.org/seti-institute/project/details/fermi-paradox14 http://mkaku.org/home/?page_id=250


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extraterrestrial species. But should we heed the advice of Stephen Hawking, and stay away from

extraterrestrials? If we look back upon our own history, we can determine that intelligent life can be

violent, but we shouldnt let that hold us back from scientific progress. After all, paranoia about the

unknown could lead to humanity down a destructive path that can only end in our annihilation.


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Bibliography

Alpha, M. (n.d.).Memory Alpha. Retrieved 11 17, 2011, from Memory Alpha: http://en.memory-

alpha.org/wiki/Portal:Main

Chaisson, E. (2010). Astronomy Today Volume I. In E. Chaisson,Astronomy Today Volume I(p. 480).

Pearson Education.

Christian, E. (n.d.). Size of the Milky Way. Retrieved 11 14, 2011, from NASA's Imagine the Universe:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980317b.html

Google. (n.d.). Google. Retrieved 11 14, 2011, from Google: http://tinyurl.com/coj889o

Kaku, M. (n.d.). The Physics of Interstellar Travel. Retrieved 11 17, 2011, from Welcome to

Explorations in Science with Dr. Michio Kaku: http://mkaku.org

NASA. (n.d.). Closest Planetary System Hosts Two Asteroid Belts. Retrieved 11 15, 2011, from NASA:

http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20081027.html

NASA. (n.d.). Cosmic Distance Scales - The Nearest Star. Retrieved 12 16, 2011, from NASA:

http://heasarc.nasa.gov/docs/cosmic/nearest_star_info.html

NASA. (n.d.).Human Space Flight (HSF) - Space Shuttle. Retrieved 11 15, 2011, from NASA:

http://spaceflight.nasa.gov/shuttle/reference/basics/

O'Neill, I. (n.d.). Could Warp Drive Become a Reality? | Astroengine.com. Retrieved 12 16, 2011, from

AstroEngine: http://www.astroengine.com/2008/07/could-warp-drive-become-a-reality/

Ravilious, K. (n.d.).Most Earthlike Planet Yet Found May Have Liquid Oceans. Retrieved 11 15, 2011,

from National Geographic News: http://news.nationalgeographic.com/news/2009/04/090421-most-earthlike-planet.html

SETI. (n.d.). SETI Institute. Retrieved 11 17, 2011, from SETI Institute: http://www.seti.org

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