The Search for Extraterrestrial Intelligence - and How You Can Help!

Back in 2015, a Russian telescope detected mysterious signals from outer space. They were coming from the direction of HD164595, a star 95 light years from Earth! Journalists began to wonder: could these signals be from an alien civilization?

Space exploration seems to fascinate rich entrepreneurs like Tesla’s Elon Musk and Amazon’s Jeff Bezos. Several billionaires have also started pouring millions of dollars into searching space for aliens. One billionaire will partner with NASA to look for life on one of Saturn’s moons! 

But you don’t need to leave Earth to look for aliens. People have been searching for signs of extraterrestrial (alien) life since the telescope was invented. The first modern SETI (Search for Extraterrestrial Intelligence) project was Project Ozma, which began in 1960. Astronomer Frank Drake used a radio telescope to search for signs of intelligent alien life. He listened for three months. But all he heard was silence and the occasional false alarm.

Did you know? 

Project Ozma was named after Princess Ozma, the ruler of the fictional Land of Oz (from The Wizard of Oz).

Still, Project Ozma sparked the interest of other astronomers. Since then, they have used many different techniques to try and answer the question: is there life beyond Earth?

So how exactly do astronomers look for extraterrestrial life? Mostly, they listen for radio waves (a type of electromagnetic radiation) coming from deep space. Sound interesting? You can help researchers sift through the data!

Why Do Astronomers Listen for Radio Waves?

You have probably listened to music that was transmitted by a radio station near you. Alien civilizations might also be sending radio signals into space.These aliens might actually be trying to reach us. Or they might be trying to communicate with each other. Maybe their radio signals end up reaching Earth by accident! 

Humans also send radio signals into space ourselves. For decades, TV and radio broadcasts from Earth have been traveling into space. One day, an alien civilization may receive these signals and try to contact us!

That’s why many SETI researchers search the sky for radio waves. This technique is sometimes called radio SETI. In fact, astronomers think that radio waves are an ideal way to communicate across the universe. That’s because the waves can travel such long distances. Also, they usually aren’t blocked by the gases and dust found in space.

Did you know? 

SETI - or Search for Extraterrestrial Intelligence - is the scientific practice of searching for intelligent aliens. The SETI Institute is a non-profit organization dedicated to SETI.

How do scientists listen for alien life? 

Astronomers often use very large satellite dishes to listen for incoming radio waves. 

These dishes are very sensitive, and can pick up many different kinds of signals. More recently, astronomers have started to use large numbers of small dishes. Small dishes can be cheaper and easier to operate than large dishes. The individual dishes are about the same size as the satellite dish you might have at home. This approach is known as “Large Number of Small Dishes” (LNSD).

Astronomers use these dishes in two main ways:

Many astronomers think that it’s best to use a combination of both methods. 

Astronomers believe certain planets, such as exoplanets located in Earth's “Goldilocks zone”, are more likely to have alien life. In these cases, it makes sense to use targeted searches. But no one really knows what alien life might look and act like, or where it might live. Aliens might be living on completely different types of planets. Wide-sky surveys would make sure scientists didn’t miss out on these planets—or these aliens! 

Did you know? 

The Allen Telescope Array (ATA) is an example of the LNSD approach to SETI. Eventually, the ATA will use 350 individual dishes to probe the sky for signals from outer space.

What happens if astronomers detect a signal?

When they detect an unusual signal, astronomers usually monitor the region more closely with more telescopes. This is an important step, because signals can often come from non-alien sources. 

For example, telescopes at the Parkes Observatory in Australia once detected radio waves. These radio waves seemed to be coming from deep space. But eventually, the astronomers discovered the true source: the microwave oven in the staff kitchen! People were reheating coffee and opening the door before the timer went off. This released another type of electromagnetic radiation called microwaves. Each release only lasted about a quarter of a second. But that’s what the telescope was picking up!

Other false alarms have come from military satellites. And that mysterious signal you read about at the start of this article? Scientists determined that it was actually coming from Earth!

Did you know? 

The world’s largest telescope is the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China. It is wider than 30 football fields!

How can you help search for extraterrestrial life?

Scientists haven’t detected a real alien message yet. But the search continues, and you can help! 

Telescopes looking for alien signals generate massive amounts of data. Through the SETI@home program, many non-scientists are helping analyze this data on their home computers. This data comes from the Arecibo telescope in Puerto Rico. 

Did you know? 

The SETI@home program was launched in 1999. Since then, over six million people have participated in this citizen science project. That’s a lot of alien hunters!

You can participate by installing the free SETI@home program. It automatically downloads data from researchers at U.C. Berkeley, and processes it when you’re not using your computer. Rather than running a boring screensaver, your computer can help search for signals sent by intelligent alien life. Happy hunting!

Did you know? 

Canadian researchers were behind a new instrument called NIROSETI. It looks for infrared signals from aliens instead of radio waves.