When looking up at the stars at night have you ever wondered if there is other life out there?
When a person realizes how many galaxies and stars are out there in the incomprehensibly large Universe,
it is only logical to ask, "Is there intelligent life out there?"
The Search for Extraterrestrial Intelligence Institute (SETI Institute), started about half a century ago with
the quest to find life in the Universe.
The key question is what to look for in order to detect extraterrestrial intelligence.
How many technological civilizations are in out there in Space?
Since the exact answer to this question is still impossible, scientists are attempting to at least approximate
how many advanced civilizations that are admitting evidence of technology.
In 1961, the famous astronomer Frank Drake
first attacked this question with his famous equation:
N = R* x Fp x Ne x Fl x Fi x Fc x L
is the number of civilizations in the galaxy in which communication may be possible is found by
multiplying all of the variables below:
represents the number of stars in the Milky Way Galaxy
is the fraction of stars that have planets around them
is the number of planets per star that are capable of sustaining life
is the fraction of planets in ne where life evolves
is the fraction of fl where intelligent life evolves
is the fraction of fi that communicate
is fraction of the planet's life during which the communicating civilizations live
Scientists do not yet have precise values for each factor, but are working to obtain more accurate information.
For example, astronomers recently found that smaller and cooler stars might be capable of supporting life on an orbiting planet.
Also, recent discoveries of Extrasolar planets, showed that planetary systems around the stars might be something quite common.
Based on our own human advancements, scientists believe radio signals are probably the most common and easy to
detect sign of a technologically advanced civilization. Using large radio telescopes, astronomers have the ability
to detect such signals.
Astronomers could even detect unintentional signals sent as a form of internal communication, such as our radio or television.
Similar technology from extraterrestrials would emit waves or signals that travel through the space.
Astronomers started to "listen" to nearby stars for radio signals about 50 years ago.
, an ambitious project used some of the world largest radio telescopes in Australia,
West Virginia and Puerto Rico to "listen" to 800 nearby sun-like stars.
The technology was so sensitive that it would be able to register radio signals as strong as the signals sent by Earth's military radar.
The immediate data processing also allowed elimination of all signals originating on Earth.
The fact that astronomers failed to register signals, may simply mean that they did not listen
to the right "radio station" at right time.
Searching for optical signals is a relatively young field in the search of Extraterrestrial Intelligence.
Powerful lasers which emit very strong and focused optical signals could be detected from space.
Astronomers at Harvard University have been conducting regular observations in search of such optical signals.
The Planetary Society also surveys the sky for optical extraterrestrial signals using a powerful 72 inch telescope.
is quite promising because the highly focused laser beam is few times brighter than the Sun and could
be used to transmit large amounts of data.
Broadcasting or sending decipherable messages to the other solar systems currently seems like a castaway
sending a message in the bottle hoping someone will find the bottle in the vast ocean.
However, with the enormous advancement in technology, we are approaching greater and greater capabilities.
Actually, astronomers sent a message in 1974 to the globular cluster M13
which contains about million stars.
The message contains coded signals. One of the major obstacles is the distance.
For example the M13 stars are about 13,000 ly
way of the Earth.
It means that if somebody does respond to our message, we won't receive the answer until 26,000 years later
and by then our civilization will probably be gone.
spacecraft have information for alien civilizations about Earth.
even carry a record of the Earth and major achievements of the human civilization.
These spacecrafts are all currently headed out of the Solar System and some alien civilization may eventually
discover the information and respond. We really have no way of knowing how advanced such alien civilizations could be.
They could be so advanced that they could have already found ways of surpassing what scientists deem the laws of physics.
Perhaps, they have found ways to travel much faster than the speed of light