Here’s how astronomers search for alien life beyond Earth

We have long been fascinated by the idea of ​​alien life. The earliest written records presenting the idea of ​​”alien” are seen in the satirical works of Assyrian writers Lucian of Samosata dating from 200 AD.

in a novel, Lucian wrote about a trip to the Moon and tell stories about the strange life he lived there – from three-headed vultures to lice the size of elephants.

After 2,000 years, we are still writing stories of epic adventures beyond Earth to meet creatures from other worlds like the story in Hitchhiker’s Guide. Stories like these entertain, inspire, and keep us on a constant quest to find out if science fiction will one day become science fact.

The type of alien life that might exist outside of Earth

When we look at life beyond Earth, we are faced with two possibilities. We might find basic microbial life lurking somewhere in the Solar System or we might find signals from intelligent life somewhere far away.

Not like in the movies Star Wars, we’re not talking about very distant places in other galaxies, but around the nearest stars. It is this second possibility that excites me and should excite all of you as well. The discovery of certain life forms out there will change our perspective on the universe.

In the last 80 years, programs dedicated to the search for extraterrestrial intelligence (extraterrestrial intelligence or SETI) has been working tirelessly to find the cosmic “hello” that takes the form of a radio signal.

The reason we think that intelligent life would communicate via radio waves is due to the ability of radio waves to travel great distances in space, and are rarely disturbed by dust and gas between stars. If life were out there trying to communicate, it’s pretty certain they would do so via radio waves.

Three radio facilities used in the Breakthrough Listen Initiative. From left to right: Robert C. Byrd Green Bank 100m Telescope, 64m Murriyang (Parkes) Radio Telescope, MeerKAT array of 64 antennas. NRAO, CSIRO, MeerKAT

1. How to search for alien life: listen to the stars

One of the most interesting quests to date is programs Breakthrough Listenthe largest scientific research program dedicated to finding evidence of intelligent life beyond Earth.

It is one of many projects funded by US-based Israeli entrepreneurs Julia and Yuri Milner, with no small amount of money. Over a ten year period, a total of US$100 million or equivalent to Rp. 1.5 trillion will be invested in this effort, and they have a huge, very heavy task.

Breakthrough Listen is currently targeting a search at the nearest million stars in hopes of identifying unnatural radio signals of alien origin. Using telescopes around the world, from the 64 meter long Murriyang Dish (Parkes) in Australia to the 64 antennae of MeerKAT in South Africa, this search was an extraordinary one. But these are not the only ones.

Lurking in the Cascade Mountains north of San Francisco lies Allen Telescope Arraythe first radio telescope built from the ground up specifically for SETI use.

This unique facility is another exciting project being able to search for signals every day of the year. The project is currently developing hardware and software on the original dish, including the ability to target multiple stars at once. This project is part of the non-profit research organization, SETI Institute.

2. Look for space lasers

The SETI Institute is also looking for signals that could be called “space lasers”.

Some astronomers have hypothesized that intelligent beings might use enormous lasers to communicate with or even to propel spacecraft. This is because even on Earth we are investigating laser communication and light screen which is driven by a laser.

To search for mysterious flashes in the night sky, we need special instruments at various locations around the world that are currently being developed and that we are using. This is an area of ​​research I am excited to see progress on and look forward to the results.

At the time of writing this article, unfortunately no alien laser signals have been found.

Challenge looking for aliens

It’s always interesting to contemplate who else might live in the universe, but there is one problem we must overcome in order to meet or communicate with aliens. That problem is the speed of light.

Everything we rely on to communicate through space requires light, and light travels very fast. This is where my optimism for finding smart life begins to fade. The universe is really big.

As an illustration, humans began using radio waves to communicate over long distances in 1901. First transatlantic signal only 122 light years away, or spanning only 0.0000015% of the stars in the Milky Way.

The small blue dot in the center of the square is the current signal transmission range of humans in our galaxy. Adam Grossman/Nick Risinger

Is your optimism fading too? That’s okay, because here’s the wonderful thing… we don’t have to find life to know that it’s out there, somewhere.

When we consider the trillions of galaxies, the septillion stars, and possibly many more planets that exist in the observable universe, it almost seems impossible that we are alone.

We cannot completely limit the parameters we need to estimate how many other life forms might be out there, as Frank Drake proposed, by using approximations and simulation our best answer, the best answer right now is that there are tens of thousands of possible civilizations out there.

The universe may have an infinite size, but that’s too much for my workday brain to comprehend.

Don’t forget the little alien

So, even if we search diligently for signals, we probably won’t find intelligent life in our lifetimes. But there is still hope for other aliens.

They are hiding in plain sight, on the planets of the Solar System. In the coming decades, we will explore the moons of Jupiter and Saturn like never before on a hunting mission for traces of life.

Jupiter and the icy moon Europa. Concepts related to the Clipper mission are being developed. NASA/JPL

Mars will continue to be explored by humans which will eventually allow us to discover and take samples of new, unexplored areas.

Even if the aliens we meet in the future are just tiny microbes, it’s still nice to know that we have friends in this universe.

Demetrius Adyatma Pangestu from Bina Nusantara University translated this article from English

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