UV light readings may be a better indicator for alien life than water

Are we alone in the universe? A new study sets out a narrow parameter within UV light measurements in which alien life can evolve.
Chris Young
NASA's exoplanet.
NASA's exoplanet.


A team of scientists from Italy investigated the importance of ultraviolet (UV) light in the search for extraterrestrial life.

In a new paper published in preprint server arXiv, they highlighted how the "presumed presence of liquid water on Circumstellar Habitable Zone (CHZ) planets does not guarantee suitable environments for the emergence of life."

So, though it's important to search for the presence of liquid water in distant rocky exoplanets, a light measurement may be equally important. Crucially, the team of scientists also determined a parameter within UV light readings in which they believe life can evolve.

Their findings show that many habitable planets identified so far may, in fact, be unsuitable for life.

UV light and the evolution of life

The authors state that the dozens of rocky exoplanets discovered in the CHZ of their star's orbit "currently represent the most suitable places to host life as we know it outside the Solar System."

Crucially, though, a delicate balance of different conditions is required for life to flourish. In fact, the scientists state that "the building blocks of life are most likely produced photochemically in the presence of a minimum ultraviolet (UV) flux." However, too much UV light can also be threatening to life.

In other words, life likely requires just the right amount of UV light to evolve. These findings point to possible new parameters in the search for alien life. In the future, for example, astronomers may be able to discount an exoplanet based on UV light readings.

Mainly, the new arguments suggest that CHZ planets orbiting stars other than Solar-type ones, with different UV to bolometric luminosity ratios, may not be able to harbor life. This could completely alter the search for alien life, as NASA has so far detected more than 5,000 exoplanets, many in the CHZ, surrounding different star types.

Are we alone in the universe?

In their study, the researchers combined the "principle of mediocrity" with recent experimental studies in order to help them define UV boundary conditions, or a UV-habitable Zone (UHZ), within which life should be able to evolve.

According to the researchers, only stars with effective temperatures of >3900 K illuminate their CHZ planets with enough UV light for life to evolve.

Using these UHZ parameters, the scientists then analyzed 17 stars harboring 23 planets in their Circumstellar Habitable Zone. They discovered that 18 of those planets were outside the UHZ they determined in their analysis.

In other words, if their science is correct, a large amount of habitable planet candidates may have to be stricken from consideration. The findings have yet to be peer-reviewed, though the new findings could completely alter our perception of our place in the universe.

On the one hand, it may lend weight to the argument that we are likely alone in the universe. On the other, it could help to narrow the search parameters and guide the search for extraterrestrial intelligence to its first successful discovery.

Add Interesting Engineering to your Google News feed.
Add Interesting Engineering to your Google News feed.
message circleSHOW COMMENT (1)chevron
Job Board