What is SETI - Search for ExtraTerrestrial Intelligence?

... and has it been successfull?

May 15, 2022

“If the government is covering up knowledge of aliens, they are doing a better job of it than they do at anything else.” - Stephen Hawking

Greetings, fellow Bohron

Drake’s equation suggests that there could be 100 to 10,000 intelligent civilizations in the Milky Way alone. Ever since Drake presented his work at the first meeting of Search for Extraterrestrial Intelligence (SETI) in 1961, interest in interstellar exploration rose enormously primarly because the very idea of aliens frightens our mind. As a result, a series of projects were seriously undertaken. Has any of them been succesfull?

Listening to ET

Search for Extraterrestrial Intelligence (SETI) is an umbrella term used for scientific programs to search for and detect electromagnetic signals from space, perhaps from an alien civilisation.

Radar telescopes in alignment at the National Radio Astronomy Observatory near Socorro, New Mexico. *Source*

In 1959, physicists Philip Morrison and Giuseppe Cocconi first pointed out that the possibility of searching the microwave frequency from 1 to 10 GHz could help us find intelligent signals from outer space. 1420 GHz, the emission frequency of hydrogen gas was the one in which researchers were most interested (since it is the most abundant gas in the universe).

Unfortunately, the search around this range hasn’t been fruitful. In 1960, astronomer Frank Drake worked on a SETI program, Project Ozma, at the National Radio Astronomy Observatory using a 26 m wide radio telescope. No extraterrestrial signals were ever found.

The 85-foot (26 m) Howard E. Tatel Radio Telescope at NRAO used in the project. *Source*

On 16 November 1974, a radio message of 1679 bits was sent towards globular star cluster M13 through the Arecibo radio telescope in Puerto Rico. Arecibo message carries basic information about humanity and Earth. It consists of a 23 x 73 grid pattern on which is plotted the location of the solar system, a human being illustration and some chemical formulae. Even if there is intelligent life somewhere in M13, we won’t know about it for 50,000 years because of the vast interstellar distances involved.

This is a demonstration of the message with colour added to highlight its separate parts. The binary transmission sent carried no colour information. *Source*

On August 15, 1977, the Ohio State University's Big Ear radio telescope detected a strong narrowband radio signal popularly known as The Wow! signal. The signal appeared to come from the direction of the constellation Sagittarius. Although the signal lasted just 72 seconds, it bore the expected hallmarks of extraterrestrial origin.

However, despite many attempts to follow up on the find, the so-called “Wow! Signal” has never reappeared. It remains the strongest candidate for an extraterrestrial radio transmission ever detected.

The Wow! signal represented as "6EQUJ5". The original printout with Ehman's handwritten exclamation is preserved by Ohio History Connection. *Source*

Project Phoenix was the world's most sensitive and comprehensive search for extraterrestrial intelligence by searching for radio signals. Operated entirely through private funding, Phoenix began observations in February 1995 using the Parkes radio telescope in New South Wales, Australia, then shifted near the site of Project Ozma at Green Bank and finally at Arecibo, Puerto Rico.

Phoenix searched for nearby sun-like stars since they are most likely to host long-lived planets capable of supporting life. Project Phoenix observed nearly 800 star systems all within about 200 light-years of radius. It didn’t yield any satisfactory results.

The huge radio telescope at the Arecibo Observatory in Puerto Rico. It was destroyed by high-speed hurricane winds in 2020. *Source*

In 1995, David Gedye proposed doing radio SETI using a virtual supercomputer composed of large numbers of Internet-connected computers, and he organized the SETI@home project to explore this idea. SETI@home was originally launched in May 1999 and hosted by the Space Sciences Laboratory at the University of California, Berkeley.

SETI@home software was released to the public on May 17, 1999. The software enables participants to decode radio signals received by radio telescopes. To date, the project has not confirmed the detection of any extraterrestrial intelligence signal.

SETI@Home gave rise to an active online community of volunteers and enthusiasts. *Source*

Why have we failed? Where are they?

SETI researchers believe that the following two reasons might be possible for the failure of the program to detect any ET signal:

Exclusive use of radio signals

Some have suggested that Intelligent civilizations might use laser signals instead of radio signals. A laser has a shorter wavelength i.e. more signals can be packed into one wave.

Reliance on certain radio frequency bands.

Alien life may use compression techniques or might disperse messages via smaller packages. Listening in on compressed messages that have been spread over many frequencies, we might hear only random noise.

Radio telescopes are often used by SETI projects. *Source*

On the other hand, recent research has shown that intelligent alien life might be much rare in the universe than predicted by Drake’s Equation. This is because life-supporting planets must have the right conditions for life to prosper. Some of them are:

The presence of a large moon

Earth is blessed with a large moon, which helps to stabilize the planet’s spin. Without a large moon, Earth's axis probably would have become unstable and the Earth might have tumbled, making life impossible. Mars has two tiny moons, too small to stabilize its spin, which means that Mars may have tumbled in the distant past

The presence of a Jupiter-sized planet in a solar system

Jupiter's strong gravitational field deflects passing comets and meteors into space, saving Earth from life-threatening asteroid collisions. In a solar system, where such Jupiter-sized planets don’t exist, life might be difficult to evolve into intelligent species.

Jupiter saves the earth from thousands of asteroid attacks. Source

Strong magnetic field.

A stronger magnetic field is more easily able to deflect cosmic rays and radiation that could destroy life on Earth.

Moderate speed of planetary rotation.

If a planet rotates too slowly, its one side facing the Sun would become red hot while the other would become extremely cold for long periods of time. If the rotation is too fast, extremely violent weather conditions such as monster winds and storms would make it impossible for life to persist.

If we really want to be successful in our quest to find alien life, we would have to understand the physics behind advanced civilizations. That’s what we’ll do next.

Bohring

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