Finding oxygen on other planets may not mean there's life there

On Earth, oxygen functions as both the byproduct and sustainer of life. This has generally led scientists to regard the presence of the element on other planets as a sign of alien life. According to new research, however, the production of oxygen does not necessarily indicate the existence living organisms on such planets.

 

On exoplanets—planets that orbit stars in other solar systems—the non-biological chemical reaction that occurs when water interacts with titanium oxide could alone be responsible for the release of oxygen into the atmosphere. In other words, an oxygen-rich atmosphere is not always proof that an exoplanet is flourishing with living organisms such as those found on Earth.

 

“Although oxygen is still one of the possible biomarkers, it becomes necessary to look for new biomarkers besides oxygen,” said Norio Narita of Japan’s National Institutes of Natural Science.

 

Scientists have been increasingly using NASA’s Hubble Space Telescope and similar instruments to examine the atmospheric makeup of extrasolar planets.

 

After examining stellar radiation in distant star systems similar to our own, Narita and his team discovered that liquid water could dissolve titanium oxide on a planet’s surface to create oxygen.

 

Titanium oxide occurs naturally, forming dust outflows around certain stars and supernovae. It is also present in celestial bodies such as meteorites, our very own moon, and of course, exoplanets.

 

In regards to Earth-like planets revolving around stars like our sun, as little as 0.05 percent of a planet’s surface has to contain titanium oxide to produce an amount of oxygen similar to that found in the Earth’s atmosphere. To produce similar results in an ocean-bearing planet orbiting a dimmer star, said planet would need titanium oxide to cover 3 percent of its surface.

 

The Earth, by comparison, has approximately 0.0000005 percent (or 250 square kilometers) of its surface playing host to active titanium oxide.

 

This study was published in Nature. — TJD, GMA News