Have We Been Searching for Alien Life in All the Wrong Places?

Tuesday, 28 November 2017 - 11:32AM
Alien Life
Tuesday, 28 November 2017 - 11:32AM
Have We Been Searching for Alien Life in All the Wrong Places?
Image credit: Pixabay
The first step to learning is admitting you know nothing—there's perhaps no better example of that than our search for alien life.

After years of searching for potentially habitable planets and finding thousands of candidates, while we may be on the right path to finding Earth alternatives, some scientists are arguing it's time to rethink the search for extraterrestrial life

The traditional thinking is that if a planet has liquid water, the probability of it having some form of alien life increases.

Exoplanets, like the recently discovered Ross 128 b, are ranked based on where they are in the "habitable zone" around a star because it means there could be liquid water on the planet's surface.

During a meeting of "planet hunters" in Wyoming earlier this month, scientists presented studies that suggest that liquid water alone is not enough.

"We have this stereotype that if we have oceans, we have life," said Arizona State microbial ecologist Tessa Fisher. By studying what would happen to life on an "aqua planet" (read: Waterworld), Fisher and her team determined that without rainwater washing nutrients like phosphorous from the land into the sea, there would be no ocean organisms to fill the atmosphere with oxygen.

Arizona State geologist Cayman Unterborn argued that if a planet had too much water (the study analyzed a planet with 50 times as much water as Earth's oceans), the pressure on the seafloor would prevent melting at the planet's interior, which would throw off the geological activities like plate tectonics that make life possible. 

"Habitability is not only about finding the signature of an alien life form taking a deep breath," said astronomer Elizabeth Tasker, who argues that exoplanet explorers need to think more about how planets form and how they have evolved. "We need to look carefully at picking the right planet."

A poll was taken at the meeting and the majority of those asked (47 versus 29) said that they don't think we will find life on an exoplanet by 2040. They were more optimistic about the chances for the 2050s and 2060s, but given the studies presented, if water and habitable zones remain the main criteria, we may never find what we're looking for.
Science
Space
Alien Life
Have We Been Searching for Alien Life in All the Wrong Places?
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