{"id":281191,"date":"2026-02-12T22:49:10","date_gmt":"2026-02-12T22:49:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/281191\/"},"modified":"2026-02-12T22:49:10","modified_gmt":"2026-02-12T22:49:10","slug":"astronomers-detect-a-solar-system-they-say-should-not-be-possible","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/281191\/","title":{"rendered":"Astronomers detect a solar system they say should not be possible"},"content":{"rendered":"

\n An exoplanetary system about 116 light-years<\/a> from Earth could flip the script on how planets form, according to researchers who discovered it using telescopes from NASA and the European Space Agency, or ESA.\n <\/p>\n

\n Four planets orbit LHS 1903 \u2014 a red dwarf star, the most common type of star in the universe \u2014 and are arranged in a peculiar sequence. The innermost planet is rocky, while the next two are gaseous, and then, unexpectedly, the outermost planet is also rocky.\n <\/p>\n

\n This arrangement contradicts a pattern commonly seen across the galaxy and in our own solar system, where the rocky planets (Mercury, Venus, Earth and Mars) orbit closer to the sun and the gaseous ones (Jupiter, Saturn, Uranus and Neptune) are farther away.\n <\/p>\n

\n Astronomers suspect this common pattern<\/a> arises because planets form within a disk of gas and dust around a young star, where temperatures are much higher close to the celestial body. In these inner regions, volatile compounds such as water and carbon dioxide are vaporized while only materials that can withstand extreme heat \u2014 such as iron and rock-forming minerals \u2014 can clump together into solid grains. The planets that form there are therefore primarily rocky.\n <\/p>\n

\"In<\/p>\n

\n Farther from the star, beyond what scientists call the \u201csnow line<\/a>,\u201d temperatures are low enough for water and other compounds to condense into solid ice \u2014 a process that allows planetary cores to grow quickly. Once a forming planet reaches about 10 times<\/a> the mass of Earth, its gravity is strong enough to pull in vast amounts of hydrogen and helium, and in some cases, this runaway growth produces a giant gas planet such as Jupiter or Saturn.\n <\/p>\n

\n \u201cThe paradigm of planet formation is that we have rocky inner planets very close to the stars, like in our solar system,\u201d said Thomas Wilson, an assistant professor in the department of physics at the University of Warwick in England and first author of a study on the discovery that was published Thursday in the journal Science<\/a>. \u201cThis is the first time in which we have a rocky planet so far away from its host star, and after these gas-rich planets.\u201d\n <\/p>\n

\n The unexpected rocky planet, called LHS 1903 e, has a radius about 1.7 times that of Earth, making it what astronomers call a \u201csuper Earth\u201d \u2014 a larger version of our planet with similar density and composition. But why is it there, defying logic and previous observations?\n <\/p>\n

\n \u201cWe think that these planets formed in very different environments from each other, and that is what\u2019s kind of unique about this system,\u201d Wilson said. \u201cThis outer planet, which is rockier compared to the middle two planets, shouldn\u2019t have happened, based on the standard formation theory. But what we think happened is that it formed later than the other planets.\u201d\n <\/p>\n

\n The planetary system was first discovered using a Transiting Exoplanet Survey Satellite, or TESS, a NASA space telescope launched in 2018 to discover new exoplanets. The system was then analyzed using ESA\u2019s CHaracterising ExOPlanet Satellite, or Cheops, which was launched in 2019 to study stars that are already known to host exoplanets. The researchers also used data from other<\/a> telescopes<\/a> across the world, leading to a large international collaboration.\n <\/p>\n

\"NASA's<\/p>\n

\n After they confirmed the odd finding of an \u201cinside out\u201d planetary system, the scientists tested some hypotheses to explain the presence of the outermost rocky planet, hoping to understand whether it could have formed via a collision between other planets, or if it could be the remnant of a gas-rich planet that had lost its outer envelope.\n <\/p>\n

\n \u201cWe ran a lot of dynamical analysis in this study, basically throwing these planets at each other and throwing other planets at these planets, seeing if you could remove the atmosphere, if you could create these planets via impacts,\u201d Wilson said, referring to two possible formation processes. \u201cBut we cannot make these planets this way.\u201d\n <\/p>\n

\n Once they ruled out these possibilities, the researchers landed on what Wilson calls a \u201cgas-depleted\u201d formation mechanism in which the planets formed one after another and in the opposite order to our own solar system, starting with the innermost planet and moving outward.\n <\/p>\n

\n \u201cThis formation mechanism, where you start with the inner one and then you move away from the host star, means the outermost planet formed millions of years after the innermost one,\u201d Wilson said. \u201cAnd because it formed later, there was actually not that much gas and dust in the disk left to build this planet from.\u201d\n <\/p>\n

\n In our solar system, the gas giants formed first and quickly, followed by the four inner rocky planets. There are also rocky bodies beyond the orbit of Neptune, such as Pluto, but compared with LHS 1903 e, Wilson said, they are far smaller, ice-rich and likely formed much later than the other solar system planets, as a result of collisions.\n <\/p>\n

\"A<\/p>\n

\n The finding may offer \u201csome of the first evidence for flipping the script on how planets form around the most common stars in our galaxy,\u201d according to Sara Seager, professor of planetary science and physics at the Massachusetts Institute of Technology and a coauthor of the study.\n <\/p>\n

\n However, she added, the study is centered around a difficult interpretation, so the debate remains open. \u201cEven in a maturing field, new discoveries can remind us that we still have a long way to go in understanding how planetary systems are built,\u201d she said in an email.\n <\/p>\n

\n LHS 1903 is an intriguing planetary system that can teach scientists a lot about how small planets form and evolve, according to Heather Knutson, a professor of planetary science at the California Institute of Technology who was not involved with the study. \u201cPlanet e is particularly intriguing, as it can potentially host many different kinds of atmospheres and may be cool enough for water to condense,\u201d she said in an email. \u201cThis would be a fascinating planet to observe with the James Webb Space Telescope, which might be able to tell us more about its atmospheric properties.\u201d\n <\/p>\n

\n According to Ana Glidden, a postdoctoral researcher at MIT\u2019s Kavli Institute for Astrophysics and Space Research, the four-planet LHS 1903 system can serve as a natural laboratory for studying how small planets form around a star different than our own sun. She also didn\u2019t participate in the research.\n <\/p>\n

\n \u201cThe authors reasonably conclude that the outermost planet likely formed in a region with little gas rather than losing its atmosphere through a violent collision,\u201d Glidden wrote in an email, adding that future observations may allow scientists to probe their atmospheres and better understand how different types of planets form and evolve.\n <\/p>\n

\n The formation hypothesis outlined in the paper is exciting, but planet formation is a complex process that scientists are still trying to understand, warned N\u00e9stor Espinoza, an astronomer at the Space Telescope Science Institute in Baltimore who did not work on the study.\n <\/p>\n

\n How planets form around small stars such as LHS 1903 is now a matter of debate, Espinoza added in an email. \u201cThis system adds a very interesting datapoint that will have planet formation models trying to explain it for years to come \u2014 and I\u2019m sure we will learn something new about the process of planet formation once they are compared against each other!\u201d\n <\/p>\n

\n Sign up for CNN\u2019s Wonder Theory science newsletter<\/a>. Explore the universe with news on fascinating discoveries, scientific advancements and more.<\/p>\n","protected":false},"excerpt":{"rendered":"An exoplanetary system about 116 light-years from Earth could flip the script on how planets form, according to…\n","protected":false},"author":2,"featured_media":281192,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[111,139,69,147,392],"class_list":["post-281191","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-new-zealand","tag-newzealand","tag-nz","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/281191","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=281191"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/281191\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/281192"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=281191"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=281191"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=281191"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}