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Saturn's small moon Mimas seems an unlikely suspect in the hunt for life in Earth's backyard -- it is probably best known for looking like the "Death Star" in the Star Wars films.

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Life on 'Death Star'? Saturn moon Mimas has hidden ocean

Agence France-Presse

<div><span class="fr-img-caption fr-fic fr-dib" style="width:950px"><span class="fr-img-wrap"><img src="https://od2-image-api.abs-cbn.com/prod/editorImage/half-moon-02082024.jpg" style="width:950px" class="fr-fic fr-dib" alt="The Cassini spacecraft turns the eye of its camera toward Saturn&#x27;s moon Mimas and spies the large Herschel Crater which itself looks like the iris of an eye peering out into space. NASA/JPL/Space Science Institute"/><span class="fr-inner">The Cassini spacecraft turns the eye of its camera toward Saturn&#x27;s moon Mimas and spies the large Herschel Crater which itself looks like the iris of an eye peering out into space. <em>NASA/JPL/Space Science Institute</em></span></span></span></div><div><br/></div><p>PARIS, France - Saturn&#x27;s small moon Mimas seems an unlikely suspect in the hunt for life in Earth&#x27;s backyard -- it is probably best known for looking like the &quot;Death Star&quot; in the Star Wars films.</p><p>But scientists said on Wednesday that underneath the unassuming moon&#x27;s icy shell is a vast hidden ocean that has many of the ingredients necessary to host primitive alien life.</p><p>Mimas is the latest to join a growing family of icy moons thought to harbour inner oceans in our Solar System which also includes fellow Saturn satellites Enceladus and Titan as well as Jupiter&#x27;s Europa and Ganymede.</p><p>But the inclusion of Mimas in this list has come as a surprise.</p><div><a href="https://news.abs-cbn.com/spotlight/06/15/23/nasa-finds-key-building-block-for-life-in-a-moon-of-saturn" rel="noopener noreferrer" target="_blank">NASA finds key building block for life in a moon of Saturn</a></div><div><a href="https://news.abs-cbn.com/spotlight/09/16/22/long-lost-moon-could-have-been-responsible-for-saturns-rings" rel="noopener noreferrer" target="_blank">Long lost moon could have been responsible for Saturn&#x27;s rings</a></div><p>&quot;If there is one place in the universe where we did not expect to find conditions favourable to life, it is Mimas,&quot; said Paris Observatory astronomer Valery Lainey, the lead author of a new study in the journal Nature.</p><p>Mimas, which is only 400 kilometres (250 miles) in diameter, was &quot;not at all suitable for the job&quot;, Lainey told a press conference.</p><p>Discovered by English astronomer William Herschel in 1789, the moon has the nickname &quot;Death Star&quot; because one particularly huge crater makes it look eerily similar to the space station used by Darth Vader and the villainous Empire in Star Wars.</p><p>Its craggy, crater-riddled surface is inert, showing no sign of underlying geologic activity that would suggest a hidden ocean.</p><div><strong>- &#x27;Something happening inside&#x27; -</strong></div><p>Other water worlds such as Mimas&#x27; big sibling Enceladus have smooth surfaces due to their rumbling internal oceans and many geysers.</p><p>These geysers, which shoot out material from the surface, also demonstrate that there is enough heat below to keep the water in a liquid state.</p><p>Despite its seemingly desolate exterior, Lainey said the researchers suspected that &quot;something was happening inside&quot; Mimas.</p><p>They studied how the moon&#x27;s rotation is affected by its interior structure, first publishing research in 2014 which was not strong enough to prove the presence of a hidden ocean.</p><p>Most scientists remained convinced by the other main hypothesis: that Mimas has a solid core of rock.</p><p>&quot;We could have left it there,&quot; Lainey said, adding that they were &quot;frustrated&quot;.</p><p>For the new study, the team carefully analysed the moon&#x27;s rotation and orbit in dozens of images taken by NASA&#x27;s Cassini spacecraft, which orbited Saturn from 2004 to 2017.</p><p>They detected tiny oscillations -- rotations of just a few hundred metres -- which could not have occurred if the moon had a solid rock interior.</p><p>&quot;The only viable conclusion is that Mimas has a subsurface ocean,&quot; said two US-based scientists not involved in the study.</p><p>&quot;The finding calls for a fresh take on what constitutes an ocean moon,&quot; Matija Cuk of the Search for Extraterrestrial Intelligence (SETI) and planetary scientist Alyssa Rose Rhoden wrote in a comment article in Nature.</p><div><strong>- The right stuff for life -</strong></div><p>Mimas&#x27; ice-covered shell is between 20 and 30 kilometres thick, similar to Enceladus, the study estimated.</p><p>The researchers believe the ocean formed relatively recently -- between five to 15 million years ago -- which could explain why signs of its existence have yet to rise and smooth the moon&#x27;s surface.</p><p>The ocean likely exists due to the influence of Saturn&#x27;s many other moons, whose tidal effects shook Mimas and created the necessary heat, they said.</p><p>Mimas &quot;brings together all the conditions necessary for habitability: water maintained by a heat source that is in contact with rocks so that chemical exchanges develop,&quot; said study co-author Nicolas Rambaux, also of the Paris Observatory.</p><p>So could this nearby water world harbour primitive forms of life such as bacteria?</p><p>&quot;That question will be addressed by future space missions over the coming decades,&quot; Lainey said.</p><p>&quot;One thing is certain: if you are looking for the most recent conditions of habitability to have formed in the Solar System, Mimas is the place to look.&quot;</p><div><strong>juc-dl/imm</strong></div><div><strong><br/></strong></div><div><strong>© Agence France-Presse</strong></div><div><br/></div><div><br/></div><div><br/></div>

<p>Saturn's small moon Mimas seems an unlikely suspect in the hunt for life in Earth's backyard -- it is probably best known for looking like the "Death Star" in the Star Wars films.</p>