{"id":57255,"date":"2026-06-12T11:10:00","date_gmt":"2026-06-12T15:10:00","guid":{"rendered":"https:\/\/engineering.jhu.edu\/magazine\/?p=57255"},"modified":"2026-06-12T11:10:16","modified_gmt":"2026-06-12T15:10:16","slug":"hitchhiking-on-an-interplanetary-journey","status":"publish","type":"post","link":"https:\/\/engineering.jhu.edu\/magazine\/impact\/hitchhiking-on-an-interplanetary-journey\/","title":{"rendered":"Hitchhiking on an Interplanetary Journey"},"content":{"rendered":"\n

Tiny life forms tucked into debris from an asteroid hit could catapult to other planets\u2014including Earth\u2014and survive, a new Johns Hopkins University study finds. <\/p>\n\n\n\n

The work demonstrates that a certain hardy bacterium easily withstands extreme pressure comparable to an ejection from Mars after an asteroid hit, as well as the inhospitable conditions it would face during the ensuing interplanetary journey. <\/p>\n\n\n\n

The study, published in PNAS Nexus<\/a><\/em>, suggests that microorganisms can survive remarkably more extreme conditions than expected and raises questions about origins of life. The work also has significant implications for planetary protection and space missions. <\/p>\n\n\n\n

\u201cLife might actually survive being ejected from one planet and moving to another,\u201d says senior author K.T. Ramesh<\/a>, a mechanical engineer and the Alonzo G. Decker Jr. Professor of Science and Engineering, who studies how materials behave in extreme conditions. \u201cThis is a really big deal that changes the way you think about the question of how life begins and how life began on Earth.\u201d <\/p>\n\n\n\n

Impact craters cover the surfaces of most bodies in the solar system. Mars, a planet that could harbor life, is one of the most cratered celestial bodies. Scientists know asteroid strikes can launch material across space\u2014and Martian meteorites have been found on Earth. <\/p>\n\n\n\n

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\u201cWe do not yet know if there is life on Mars, but if there is, it is likely to have similar abilities\u201d \u2014 K.T. Ramesh<\/p>\n<\/blockquote>\n\n\n\n

However, scientists have long wondered if life forms could be launched from an asteroid impact. Tucked inside ejected debris, they might land on another planet. <\/p>\n\n\n\n

Previous experiments were inconclusive and focused on organisms common on Earth, not a life form that would suit the extreme environments of other planets. <\/p>\n\n\n\n

To test a realistic planetary ejection, the team devised a way to replicate the pressure and a singular biological model: Deinococcus radiodurans<\/em>. This desert bacterium from Chile is renowned for its ability to survive inhospitable, space-like conditions\u2014from extreme cold and dryness to intense radiation\u2014thanks to its thick shell and ability to self-repair. <\/p>\n\n\n\n

\u201cWe do not yet know if there is life on Mars, but if there is, it is likely to have similar abilities,\u201d Ramesh says. <\/p>\n\n\n\n

The experiment simulated the pressure of an asteroid strike and ejection by sandwiching the microbe between metal plates and then using a gas gun to fire a projectile at it at speeds up to 300 mph, generating 1 to 3 gigapascals, or GPas, of pressure. <\/p>\n\n\n\n

For perspective, pressure at the bottom of the Mariana Trench, the deepest part of the Earth\u2019s oceans, is a tenth of a GPa\u2014so even the experiment\u2019s lowest pressure was more than 10 times that. <\/p>\n\n\n\n

Afterward, the team assessed bacteria survival and examined the survivors\u2019 genetic material for clues to how they handled the pressure. <\/p>\n\n\n\n

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