{"id":935689,"date":"2026-05-03T20:42:36","date_gmt":"2026-05-03T20:42:36","guid":{"rendered":"https:\/\/www.europesays.com\/uk\/935689\/"},"modified":"2026-05-03T20:42:36","modified_gmt":"2026-05-03T20:42:36","slug":"mars-will-tear-its-own-moon-apart-now-scientists-think-it-could-be-sooner-and-more-destructive-than-expected","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/uk\/935689\/","title":{"rendered":"Mars will tear its own moon apart. Now scientists think it could be sooner \u2013\u00a0and more destructive \u2013 than expected"},"content":{"rendered":"

The origins of Mars\u2019s two moons, Phobos and Deimos<\/a>, are still a matter of some debate.<\/p>\n

Some planetary scientists argue that they\u2019re asteroids that became captured by Mars\u2019s gravity.<\/p>\n

Others point out that\u2019s unlikely, since both are in very circular, low-inclination orbits, and they instead formed from a disc of debris blasted into Martian orbit from a giant impact.<\/p>\n

\"ImageCredit: ESA\/DLR\/FU Berlin\/G. Michael<\/p>\n

The future of Phobos<\/strong><\/p>\n

Phobos\u2019s future is also uncertain. This is the larger, innermost of the two moons and so close to the Red Planet that its orbital period is shorter than Mars\u2019s rotation.<\/p>\n

This means that tidal effects are sapping it of orbital energy and it\u2019s gradually circling nearer to the planet.<\/p>\n

The traditional belief has been that as Phobos death-spirals closer to Mars, it will pass inside the \u2018Roche limit\u2019.<\/p>\n

\"TheThe Curiosity rover captured this view of Martian moon Phobos passing directly in front of the Sun, as seen from the surface of Mars. Credit: NASA\/JPL-Caltech\/Malin Space Science Systems\/Texas A&M Univ.<\/p>\n

At that distance, the tidal forces will exceed the moon\u2019s ability to hold itself together and Phobos will be torn apart<\/a> into a rocky ring around Mars.<\/p>\n

But this prediction is neglecting some crucial details, argue Harrison Agrusa and Patrick Michel, researchers at the Observatoire de la C\u00f4te d\u2019Azur, France.<\/p>\n

Phobos is too small to have ever formed into a perfect sphere; it\u2019s elongated, like a potato pointing towards Mars.<\/p>\n

More importantly, Phobos is thought to have weak internal strength and is more like a \u2018rubble pile\u2019 held together by its own gravity.<\/p>\n

\"AnAn image of Mar’s moon Phobos captured by the Viking orbiter on 10 June 1977
Credit: NASA<\/p>\n

This means it may have a much more interesting fate before it dips inside the Roche limit.\u00a0<\/p>\n

The researchers took two different approaches to exploring the moon\u2019s future.<\/p>\n

The first is a simple mathematical analysis of factors such as the tidal strain at decreasing distance from Mars, and the shape and likely cohesive strength of Phobos.<\/p>\n

The second is a more involved computer simulation of the moon as a rubble pile \u2013 like a large clump of marbles of all different sizes \u2013 that tracks each separate particle as the balance of forces on it changes during Phobos\u2019s inward spiral.<\/p>\n

And the two methods largely agree with each other. \u00a0<\/p>\n

\"MoonMoon Phobos is spiralling towards Mars, meaning it could one day disintegrate and form rings around the Red Planet
\nUnravelling of a rubble moon<\/strong><\/p>\n

They found that if Phobos does indeed have a relatively low cohesion, its surface material will start being ripped away long before it approaches the Roche limit of around 1.6 times the radius of Mars (RM).<\/p>\n

This mass shedding occurs from two opposite parts of Phobos: on the point facing Mars, where the planet\u2019s gravitational tug is strongest; and on the far side, where the outwards-flinging centrifugal force is greatest.<\/p>\n

They calculate that the first shedding event will occur when Phobos drops to an orbital distance of about 2.25RM.<\/p>\n

Much larger shedding events then happen at around 2.15RM and 2.13RM, before finally \u2013 at around 2.09RM \u2013 two huge streams of material are wrenched from it.<\/p>\n

At this point, the moon becomes destabilised and is rapidly destroyed by tidal disruption.\u00a0<\/p>\n

\"Artist'sArtist’s impression of Mars’s moon Phobos being destroyed. Credit: Mark Garlick \/ Science Photo Library \/ Getty Images<\/p>\n

But Phobos may meet its end even before this. The large amounts of material torn from its surface would enter orbit around Mars and then later re-impact into the moon at high speeds, smashing off even more material.<\/p>\n

This could trigger a \u2018sesquinary catastrophe\u2019, with the moon being obliterated by collisions with its own stripped material.<\/p>\n

The Japanese Martian Moons eXploration (MMX) mission<\/a>, due to launch in 2026, will give us a much better idea of Phobos\u2019s internal structure, and thus its ultimate fate.\u00a0<\/p>\n

Lewis Dartnell was reading Tidal Disruptions of Rubble Piles: The Case of Phobos by Harrison Agrusa and Patrick Michel Read it online at: arxiv.org\/abs\/2602.21912<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"The origins of Mars\u2019s two moons, Phobos and Deimos, are still a matter of some debate. Some planetary…\n","protected":false},"author":2,"featured_media":935690,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3844],"tags":[70,413,16,15],"class_list":{"0":"post-935689","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-science","9":"tag-space","10":"tag-uk","11":"tag-united-kingdom"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/116512592083162735","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/935689","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=935689"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/935689\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/935690"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=935689"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=935689"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=935689"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}