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

Daniel Tarade
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When astronomers search for extraterrestrial life, they often have to listen for radio waves coming from deep space. If you’re interested, 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. 

Radio telescopes near Narrabi, Australia
Radio telescopes near Narrabi, Australia (Source: CSIRO [CC BY 3.0] via Wikimedia Commons).

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:

Astronomers use wide-sky searches as well as targeted searches
Astronomers use wide-sky searches as well as targeted searches (© 2019 Let’s Talk Science).

 

Infographic - Text Version

In a wide-sky survey, astronomers scan large areas of sky. This way, astronomers can monitor a greater number of planets, stars and galaxies. But there’s a drawback to this technique. Because the dishes do not focus on specific areas, they can only pick up the most powerful signals.

In a targeted search, astronomers point the dishes toward a specific area. This way, astronomers can study objects in more detail.

 

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. 

Starting Points

Connecting and Relating

  • What do you think people find so interesting about the idea that there might be extraterrestrial life? 
  • Would you be interested in being involved in a crowdsourcing research project, like seti@home, to help scientists detect alien signals? Why or why not? 
  • What message would you send into deep space?
  • How would you feel if we did receive radio signals from an extraterrestrial source?

Connecting and Relating

  • What do you think people find so interesting about the idea that there might be extraterrestrial life? 
  • Would you be interested in being involved in a crowdsourcing research project, like seti@home, to help scientists detect alien signals? Why or why not? 
  • What message would you send into deep space?
  • How would you feel if we did receive radio signals from an extraterrestrial source?

Relating Science and Technology to Society and the Environment

  • Who should fund research into extraterrestrial life? Why? 
  • Have there been any direct or indirect benefits to society and/or science and technology as a result of SETI research? (Note: This question may require additional research.)
  • Do you think that millionaires will find extraterrestrial life before astronomers in governments or universities? Explain.

Relating Science and Technology to Society and the Environment

  • Who should fund research into extraterrestrial life? Why? 
  • Have there been any direct or indirect benefits to society and/or science and technology as a result of SETI research? (Note: This question may require additional research.)
  • Do you think that millionaires will find extraterrestrial life before astronomers in governments or universities? Explain.

Exploring Concepts

  • What kind of extraterrestrial signals are astronomers searching for, and why? 
  • What approaches are taken to searching for alien signals? 
  • What makes radio waves a good potential source of alien communication?
  • Compare and contrast targeted searches with wide-sky surveys.

Exploring Concepts

  • What kind of extraterrestrial signals are astronomers searching for, and why? 
  • What approaches are taken to searching for alien signals? 
  • What makes radio waves a good potential source of alien communication?
  • Compare and contrast targeted searches with wide-sky surveys.

Nature of Science/Nature of Technology

  • How likely is it that scientists even know what signs of extraterrestrial intelligence would even look like, given how different those life forms might be from us?
  • Do you think that astronomers have all of the technologies they need to search for extraterrestrial life? Explain.

Nature of Science/Nature of Technology

  • How likely is it that scientists even know what signs of extraterrestrial intelligence would even look like, given how different those life forms might be from us?
  • Do you think that astronomers have all of the technologies they need to search for extraterrestrial life? Explain.

Media Literacy

  • Which movies have you watched that are about searching for aliens? How realistic are these movies? Are there aspects of the story that are based on reality? Is any “real science” integrated into these stories? How so? (e.g., Contact (1997), etc.)

Media Literacy

  • Which movies have you watched that are about searching for aliens? How realistic are these movies? Are there aspects of the story that are based on reality? Is any “real science” integrated into these stories? How so? (e.g., Contact (1997), etc.)

Teaching Suggestions

  • This article can be used for Space, Engineering & Technology, and Math and Physics teaching and learning related to telescopes and radio waves. Concepts introduced include extraterrestrial life, SETI, radio telescopes, satellite dishes and microwaves.
  • After reading the article, teachers could have students discuss the pros & cons of SETI research, using a Pros & Cons Organizer. Ready-to-use Pros & Cons Organizer reproducibles are available in [Google doc] and [PDF] formats.

Teaching Suggestions

  • This article can be used for Space, Engineering & Technology, and Math and Physics teaching and learning related to telescopes and radio waves. Concepts introduced include extraterrestrial life, SETI, radio telescopes, satellite dishes and microwaves.
  • After reading the article, teachers could have students discuss the pros & cons of SETI research, using a Pros & Cons Organizer. Ready-to-use Pros & Cons Organizer reproducibles are available in [Google doc] and [PDF] formats.

Learn more

Seti@Home

A more detailed history and summary from The Planetary Society of the SETI@Home program.

Why the $100m Breakthrough Listening Project may be a waste of time

Article for The Conversation with a scientist who argues that listening for radio signals may not be the best way to find aliens and discusses why we haven’t found them yet.

Mysterious radio signal detected by Russian telescope was actually from Earth (2016)

Article from CBC News about a radio signal originally thought the have been from space, but was actually from Earth!

A History of SETI

The SETI Institute provides a historical overview of the organization.
 

References

Cohen, N., & Hohlfeld, R. (2006). Smarter SETI strategy. Sky & Telescope.

Drake, N. (2015, April 10). Rogue microwave ovens are the culprits behind mysterious radio signals. National Geographic.

Garber, S. (1999). Searching for good science: The cancellation of NASA's SETI program. Journal Of The British Interplanetary Society, 52, 3-12.

The Planetary Society. (2019). SETI@home.

Schulze-Makuch, D. (2015, August 11). The most Earthlike planet yet makes a good target for SETI. Air & Space.

SETI Institute. (2018, April 23). Protocols for an ETI signal detection.

SETI Institute. (2019). Allen telescope array overview.

SETI Institute. (2019). Broadcasting a message.

SETI Institute. (2019). History of the SETI institute.

SETI Institute. (2019). Project phoenix.

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