SETI, the Search for Alien Life

Do aliens exist? For a long time, people have been so fascinated by the possibility that we are not alone in the universe that there are groups of researchers exploring space to investigate the existence of extraterrestrial civilizations. These efforts to discover intelligent life on space are referred to as SETI. Here, we explore what SETI is and whether there is any evidence that aliens exist.

Radio Telescope Used in Project OZMA

Radio Telescope Used in Project OZMA Image Source 

What Is SETI?

SETI stands for Search for Extraterrestrial Intelligence. Its purpose is to investigate whether intelligence life exists anywhere else in the universe apart from Earth. SETI refers to a series of exploration projects that aim to detect radio signals originating from outer space by scanning the skies and monitoring any such signals. It refers to all the efforts to find evidence of intelligence life performed by scientists operating independently all over the world.

Some of the Remarkable SETI Projects

Efforts to find extraterrestrial life began as early as 1896 when Nikola Tesla proposed the use of radio waves to detect Martian signals. In 1924 during the National Radio Science Day, a radio receiver was used to listen to Martian signals.

In 1960, Frank Drake launched Project OZMA, which became the first systematic effort to search for extraterrestrial radio signals. Drake also developed a binary coded system of communicating with aliens. He composed the first interstellar message to be transmitted to any existing extraterrestrial civilizations. This message is referred to as the Arecibo Message of November 1974. Drake’s messages were the ones placed on the plaques of Pioneer 10 and 11 missions and voyager spacecraft just in case of an encounter with aliens.

The NASA SETI program referred to as High Resolution Microwave Survey was one of the most ambitious projects. Shortly after, the US congress stopped funding NASA’s SETI efforts. However, independent projects funded by private donations continued monitoring alien life by doing radio experiments

In 1995, SETI received private funding and Project Phoenix was established. This is the most sensitive project, as it conducts a more targeted search and is much more effective than OZMA. It uses a network of large radio telescopes scanning 28 million radio frequencies per second and investigating nearby stars that are almost similar to the solar system.

The SERENDIP Experiment by University of California, Berkeley surveys the sky and collects enormous amount of data that requires enormous amounts of computing power to process. To ease this burden, there is a screen saver program that makes it possible to distribute the computing power to various computers offered by volunteers.

Project Phoenix

Project Phoenix Image Source:

Myths about SETI

Whether aliens exist is a subject that captures people’s imagination. This curiosity plus the portrayal of aliens in science fiction movies fuel some myths about SETI.

One such myth that is very popular is that SETI is a secret organization/agency known as National SETI Agency, and which controls and coordinates all SETI activities all over the world. This is not true. SETI is just a field of research carried out by independent groups of researchers operating in different countries. There is no single organization coordinating these activities.

Another myth is that all radio telescopes are dedicated to the search for extraterrestrial beings. In reality, the amount of time spent in SETI activities only makes up a little fraction of the astronomy observations conducted all over the world. In fact, SETI accounts for only a tiny portion of radio astronomy.

The myths that SETI is an agency and that all telescopes are dedicated to searching for alien life give rise to another myth that SETI has failed in its mission to discover alien life. It is too early to make this conclusion. We have only scratched the surface as far as space exploration is concerned and there is so much more to explore.

Is It Possible To Communicate With Aliens if They Exist?

One way of communicating with extraterrestrial civilizations would be to send spacecrafts bearing messages. Actually, this has already been done. Several space probes set to explore interstellar space indefinitely are equipped to communicate with extraterrestrial civilizations. Pioneer 10 and 11 have an engraved plaque with a message just in case they encounter extraterrestrial civilization and Voyager 1 and 2 have a recorded message made up of words and music.

However, interstellar travel is way too expensive and requires enormous amounts of energy. A more feasible way of communicating with any intelligent life out there is to use interstellar communication, pioneered by Phillip Morrison, Giuseppe Cocconi and Frank Drake. This communication involves the use of radio telescopes to monitor leaking radio signals from other civilizations. A number of coded messages have been sent out just in case an extraterrestrial civilization also has a SETI program, which can detect the signals and respond.

Another advantage of using radio telescopes is that radio waves can travel far in space and are not absorbed by the thick clouds of gas and dust that occupy many regions of space. They are also effective during the day and night.

Optical SETI is another approach that uses ordinary telescopes with special detectors attached to find short laser pulses coming from distant worlds.

Giuseppi Cocconi Philip Morrison Frank Drake

Left to right: Giuseppi Cocconi, Philip Morrison, Frank Drake Image Source

What Is The Water Hole?

The water hole is a 300 MHz wide part of the radio spectrum. It extends from 1420 MHz to 1720 MH, which is the area corresponding to radio frequencies that emit hydrogen atoms and hydroxyl molecules. These two combine to form water, which is the basis of life. This section of the spectrum may be favored by water-based life allowing interstellar communication. 1420MHz is a universal radio channel and hydrogen gas found in space emits radio signals at this frequency.

Would SETI Telescopes Recognize Intelligent Messages from Alien Civilizations?

SETI uses advanced telescopes and would be able to detect radio signals from aliens. The first ever radio signal received from space was LGM-1. This was a regularly repeating blip that excited scientists so much that they imagined it was coming from `Little Green Men’, hence the name LGM-1. To their disappointment, the signal was from a pulsar, which is an extremely dense celestial object created when a star undergoes gravitational collapse and rotates so rapidly that it emits pulses of radio waves.

Would Aliens Be Able To Communicate With Us?

Our radio and television signals from earth travel into space at the speed of light and may be detected by other civilizations out there. Just like we leak radio signals into space, we assume that any intelligent life out there would have discovered radio signals too. SETI’s purpose is to detect any radio signal originating from another part of the universe where intelligent life exists. If there is any intelligent civilization out there, they would know that there might be other intelligent civilizations out there and try to transmit signals to communicate. Researchers use large radio telescopes to monitor and detect radio signals originating from other intelligent civilizations.

SETI@home  Arecibo Radio Telescope

SETI@home Arecibo Radio Telescope Image Source

What is The Logic behind SETI?

If there is life on earth in our galaxy, we assume that there might be life in other galaxies. Evolution that occurred on earth could have occurred anywhere else in the universe. Scientists presume that evolution occurred throughout the entire universe and there may be about 10 million advanced civilizations in our galaxy only.

The Drake Equation estimated the number of intelligent civilizations likely to be out there as more than a 1000.  Some scientists believe that the recent evidence of extra solar planets and the likelihood that biology is a common phenomenon in the universe are possible signs that there is intelligent life in space.

Who Pays for SETI Projects?

Since the U.S Congress cut funding for NASA’s SETI efforts, SETI projects are funded through private donations.

SETI projects are highly complex because they involve listening to a large number of frequencies. It is like a radio that listens to all kinds of frequencies including radio, radar, satellite TV, garage door openers, and all other signals all the time. The data collected requires massive computational resources to process.

Processing all the collected data would be so expensive that SETI researchers have come up with a creative way of processing this information. SETI@Home screen saver program distributes the data to home computers for processing.

Is There Any Evidence That Aliens Exist?

So far, there is no evidence of the existence of extraterrestrial civilizations. No radio or optical signals originating from intelligent life in space have been detected. If alien life exists, they have not received and responded to our signals or we are yet to detect theirs signals. However, scientists are not about to give up. The search goes on. We have just scratched the surface and there is a lot of out there to explore and a lot more to discover.

What Is The Future of SETI?

Scientists are not about to give up on the search for extra terrestrial intelligence. There are plans for more aggressive and comprehensive explorations. For example, the SETI Institute plans to build the Allen Telescope Array that will be dedicated to scanning the skies. There are plans to construct massive radio telescopes and use more optical telescopes that are advanced in sophistication.

The Allen Telescope Array

The Allen Telescope Array Image Source

How You Can Get Involved In Searching for Alien Life

If you are fascinated by the idea that there may be aliens, you can play a part in the search for intelligent life. SETI@Home has a screen saver program where volunteers offer their computer to process data collected from space. You just have to visit the website, download the software.  and install it on your computer so that it processes SETI data when idle.