{"id":171770,"date":"2025-09-21T12:29:09","date_gmt":"2025-09-21T12:29:09","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/171770\/"},"modified":"2025-09-21T12:29:09","modified_gmt":"2025-09-21T12:29:09","slug":"the-earth-may-not-be-as-extraordinary-as-we-think-study-finds-earthlike-planets-are-common-but-not-so-for-water-worlds","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/171770\/","title":{"rendered":"\u201cThe Earth May Not Be as Extraordinary as We Think\u201d: Study Finds Earthlike Planets Are Common, but Not So for ‘Water Worlds’"},"content":{"rendered":"

An international team of scientists studying potential water worlds<\/a> has determined that although sub-Neptune<\/a> exoplanets made up of mostly water are likely rare, Earthlike planets<\/a> may be much more common than previously thought.<\/p>\n

Led by researchers from ETH Zurich, the Max Planck Institute for Astronomy in Heidelberg, and the University of California, Los Angeles (UCLA), the findings may decrease the overall chances of life in the cosmos<\/a> since water worlds were a common target for astrobiologists<\/a>, but increase the chances of finding life on Earthlike planets that are yet to be discovered.<\/p>\n

In the 30 years since astronomers first discovered a planet outside of our solar system, over 5,000 exoplanets<\/a> have been spotted orbiting distant stars. Most are larger worlds<\/a> since they are easier to spot with current telescopes. Although many of these larger worlds<\/a> are gas giants like Jupiter<\/a> that would be incapable of supporting life as we know it, scientists searching the cosmos for signs of life<\/a> have focused a lot of attention on a smaller class of common exoplanets called sub-Neptunes.<\/p>\n

Larger than Earth but smaller than Neptune, many of these planets formed far away from their host stars beyond what is known as the ice barrier, where surface water would freeze. Some planet formation models have suggested that these sub-Neptunes gather their H2O beyond the ice barrier and then the ice melts to form largely ocean worlds with hydrogen-rich atmospheres as they drift closer to the host star. Sometimes called water worlds, scientists refer to these planets as Hycean, a combination of \u201chydrogen\u201d and \u201cocean.\u201d<\/p>\n

Because life on Earth requires water, astrobiologists have targeted water worlds as one potential place to look. The excitement was raised further in April 2024 when University of Cambridge astronomers spotted a sub-Neptune hycean world called K2-18b\u00a0that looked like a perfect place for life to thrive.<\/p>\n

In a statement<\/a> announcing the new study, the researchers highlighted what they termed a \u201cfundamental vulnerability\u201d in the water world theory. Specifically, sub-Neptunes likely undergo a developmental phase where they are covered in a hot magma ocean, creating a hydrogen shell that persists for millions of years. However, previous models appear to have ignored any \u201cchemical coupling\u201d that occurred between the atmosphere and the planet\u2019s interior.<\/p>\n

To conduct new sub-Neptune formation simulations that account for chemical coupling, the team calculated what they called the \u201cequilibrium state\u201d of 26 different components for a total of 248 model planets.<\/p>\n

\u201cWe have now factored in the interactions between the planet\u2019s interior and its atmosphere,\u201d explains Aaron Werlen, a researcher on Dorn\u2019s team and lead author of the study.<\/p>\n

According to the statement, the computer simulations revealed that the previously unaccounted-for chemical processes \u201cdestroy most H2O water molecules.\u201d This means that Hydrogen (H) and oxygen (O) attach themselves to metallic compounds that largely \u201cdisappear\u201d into the core of the planet.\u00a0As a result, these worlds have much less water than previously believed.<\/p>\n

\u201cWe focus on the major trends and can clearly see in the simulations that the planets have much less water than they originally accumulated,\u201d Werlen explained. \u201cThe water that actually remains on the surface as H2O is limited to a few per cent at most.\u201d<\/p>\n

Caroline Dorn, a professor of exoplanets at ETH Zurich and study author, said their calculations showed that there are \u201cno distant worlds with massive layers of water where water makes up around 50 percent of the planet\u2019s mass,\u201d as most previous planetary formation models had predicted.<\/p>\n

\u201cHycean worlds with 10-90 percent water are therefore very unlikely,\u201d the researcher added.<\/p>\n

One unexpected result from the study was that, although water worlds were less likely to exist, the number of Earth-like planets with the potential to support life was more common than previously thought.<\/p>\n

\t\t <\/p>\n

\t\t\t
\n\t\t\t\t\"Credit:\t\t\t<\/a>
\n\t\t
\n\t\t\t\t\t <\/p>\n

\u201cThe Earth may not be as extraordinary as we think. In our study, at least, it appears to be a typical planet,\u201d Dorn explained.<\/p>\n

In their conclusion, the researchers note that their findings will have \u201cfar-reaching implications for theories of planetary formation and the interpretation of exoplanetary atmospheres.\u201d Although their findings may decrease the overall chances of finding life beyond Earth, the increase in Earthlike planets likely increases the chances of discovering life forms similar to those found on Earth.<\/p>\n

The study authors also note that future observatories that are more powerful than those currently available will likely be needed to confirm the prevalence of Earthlike planets discovered by their models.<\/p>\n

\u201cConditions conducive to life, with sufficient liquid water on the surface, are likely to exist only on smaller planets, which will probably be observable only with observatories even better than the James Webb Space Telescope,\u201d they explained.<\/p>\n

The study \u201cSub-Neptunes Are Drier Than They Seem: Rethinking the Origins of Water-Rich Worlds<\/a>\u201d was published in the Astrophysical Journal Letters.<\/p>\n

Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X<\/a>, learn about his books at plainfiction.com<\/a>, or email him directly at christopher@thedebrief.org<\/a>.<\/p>\n

\t\t\t\t\t\t\t\t\t