Have We Already Found Alien Life?

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Exciting rumors are buzzing in the world of astrobiology.

The James Webb Space Telescope (JWST), which has been exploring the universe in incredible detail since 2022, might have detected signs of life beyond Earth.

According to astrophysicist Rebecca Smethurst, there could be strong evidence of a biosignature on an exoplanet soon.

But let’s not get too excited just yet.

A biosignature is a signal that might indicate life, but it could also be produced by non-living processes.

So, while intriguing, it’s not definitive proof of extraterrestrial life. MIT astrophysics professor Sara Seager reminds us that while many hope this will be the year for groundbreaking discoveries, robust findings are still a way off.

One major challenge in identifying alien life is defining what life is. On Earth, life involves DNA, carbohydrates, and liquid water, but life elsewhere could use different chemistry, like liquid methane or silicon.

A key concept is that life tends to exist far from chemical equilibrium.

For example, Earth’s atmosphere contains both oxygen and methane, which react to form carbon dioxide and water.

Their coexistence suggests a continuous replenishing process, likely due to life.

Clues from Mars

In December 2004, scientists detected methane in Mars’ atmosphere using the Mars Express orbiter.

This gas is mostly produced by living organisms on Earth but can also come from geological activity.

The presence of underground water on Mars suggests the possibility of microbial life.

Oceans on Europa

Jupiter’s moon Europa is another exciting candidate. It has an icy surface but possibly harbors an ocean beneath.

In 2023, the JWST detected carbon dioxide on Europa’s surface, hinting that it might come from an ocean below, potentially supporting life.

Distant Exoplanets

Beyond our solar system, astronomers have discovered over 5,000 exoplanets.

Last fall, a team of U.S. and U.K. astronomers found methane, carbon dioxide, and maybe dimethyl sulfide (DMS) around the star K2-18b.

On Earth, DMS is produced by living organisms.

However, detecting these molecules from such a great distance is extremely challenging, and some experts are skeptical about the findings.

The Search for Technosignatures

While biosignatures are promising, finding a technosignature—a sign of advanced technology—would be even more convincing.

For instance, nitrogen trifluoride, used in manufacturing on Earth, doesn’t occur naturally and would be a clear sign of technological life.

Future Missions and Patience

Proving extraterrestrial life’s existence means studying it up close, which is a significant challenge.

Mars’s microbes could be deep underground, and life on distant stars is even harder to reach.

However, icy moons like Europa might be more accessible. NASA’s Europa Clipper, launching in October, will search for life signs in Europa’s geysers.

If promising, future missions might explore its subsurface oceans directly.

Astrobiologist Marc Neveu and Seager both believe the search for alien life will be a gradual process.

Just as exoplanets were once doubted but are now widely accepted, signs of alien life will likely follow the same path from rare and uncertain to common and confirmed.

So, while we may not have definitive proof of alien life yet, the search is advancing, and maybe, just maybe, it’s already begun.


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