Communicating with Aliens — Reading Comprehension

Extraterrestrial communication is a scientific challenge that involves sending and receiving messages across vast distances in space. The question of whether we could ever talk to intelligent alien life is important because it addresses our place in the universe and the limits of technology. The nearest stars, such as Proxima Centauri, are over four light-years away, which means even a simple exchange would take decades. Scientists have already attempted to contact potential alien civilizations and are still debating if we should continue these efforts.

Distance and Time: The Challenge of Space Communication
Space is incredibly vast. A light-year is the distance light travels in one year—about 9.46 trillion kilometers. Proxima Centauri, the closest star system to Earth, is 4.2 light-years away. This means any message sent from Earth would take 4.2 years to arrive, and a reply would take another 4.2 years. Communicating with even the nearest alien civilization would be extremely slow. For example, the famous Arecibo message was sent in 1974 toward a star cluster 25,000 light-years away. The Voyager spacecraft, launched in the 1970s, carry Golden Records containing sounds and images from Earth, but they are not directed at any specific star and will take thousands of years to reach another system.

What Messages Should We Send?
Because we do not know what alien life is like, scientists focus on sending universal concepts such as mathematics. Prime numbers—numbers that can only be divided by 1 and themselves, like 2, 3, 5, 7, and 11—are often used because they show an understanding of mathematics and intelligence. The Arecibo message used a pattern of 1,679 bits (a product of two prime numbers) to demonstrate this. Pictures and music are also sent in hopes that images and sounds might be interpreted by other intelligent beings. However, there is a controversy called Active SETI (or METI): some scientists warn that announcing ourselves could be dangerous if unknown civilizations are hostile. Others argue that the potential for knowledge outweighs the risks.

What Would Aliens Be Like?
Scientists think it is unlikely that aliens would look like humans. Evolution on another planet would probably lead to life forms very different from us, possibly even microbial or beyond our current understanding. The discovery of even simple life, such as bacteria, would be transformative for science, showing that life can arise in many places. The existence of intelligent aliens would have even greater impact, potentially changing our view of ourselves and our place in the universe. The search for extraterrestrial intelligence connects to the scientific principle that systems interact and evolve in response to their environments.

In summary, communicating with aliens involves overcoming huge distances and making careful choices about what to send. It raises scientific, ethical, and philosophical questions about contact with other life forms. Whether or not we ever receive a reply, the search for extraterrestrial communication continues to drive scientific discovery.

Interesting Fact: The Voyager Golden Records include greetings in 55 languages, music from around the world, and even the sounds of a heartbeat and a whale song.

How far away is Proxima Centauri from Earth?

What was the Arecibo message?

What are Golden Records?

What does 'extraterrestrial' mean in the passage?

In the passage, what does 'universal' mean?

Why do scientists use prime numbers in messages to aliens?

Why is there a debate about Active SETI or METI?

If a message is sent to Proxima Centauri, how long would it take to get a reply?

True or False: The Voyager Golden Records are directed to a specific planet.

True or False: Scientists expect that aliens will look just like humans.