{"id":3222,"date":"2024-03-20T16:10:00","date_gmt":"2024-03-20T16:10:00","guid":{"rendered":"https:\/\/new.www.purdue.edu\/newsroom\/?p=3222"},"modified":"2025-07-30T13:41:29","modified_gmt":"2025-07-30T17:41:29","slug":"icy-impacts-planetary-scientists-use-physics-and-images-of-impact-craters-to-gauge-the-thickness-of-ice-on-europa","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/newsroom\/2024\/Q1\/icy-impacts-planetary-scientists-use-physics-and-images-of-impact-craters-to-gauge-the-thickness-of-ice-on-europa","title":{"rendered":"Icy impacts: Planetary scientists use physics and images of impact craters to gauge the thickness of ice on Europa"},"content":{"rendered":"<div class=\"purdue-initial-words-wrap\"><p class=\"purdue-initial-words\">WEST LAFAYETTE, Ind. &mdash;<\/p> \n<p>Sometimes planetary physics is like being in a snowball fight. Most people, if handed an already-formed snowball, can use their experience and the feel of the ball to guess what kind of snow it is comprised of: packable and fluffy, or wet and icy.<\/p>\n<\/div>\n\n\n<p>Using nearly the same principles, planetary scientists have been able to study the structure of Europa, Jupiter\u2019s icy moon.<\/p>\n\n\n\n    <div  class=\"purdue-home-quick-links-static \">\n        <div class=\"tagged-header-container\">\n\n            <h2 class=\"tagged-header\"><span>Additional Information<\/span><\/h2>\n        \n        <\/div>\n\n       <ul class=\"quick-links-content\">\n                                        <li class=\"quick-link__item\">\n                                                                <a class=\"quick-link__link\"\n                                    href=\"https:\/\/www.purdue.edu\/newsroom\/releases\/2022\/Q1\/when-worlds-collide-studying-impact-craters-to-uncover-the-secrets-of-the-solar-system.html\" target=\"_blank\">\n                                    When worlds collide: Studying impact craters to uncover the secrets of the solar system                                <\/a>\n                            <\/li>\n                                                <li class=\"quick-link__item\">\n                                                                <a class=\"quick-link__link\"\n                                    href=\"https:\/\/www.purdue.edu\/newsroom\/releases\/2022\/Q3\/breaking-in-a-new-planet.html\" target=\"_blank\">\n                                    Breaking in a new planet                                <\/a>\n                            <\/li>\n                                                <li class=\"quick-link__item\">\n                                                                <a class=\"quick-link__link\"\n                                    href=\"https:\/\/www.purdue.edu\/newsroom\/releases\/2023\/Q1\/purdue-scientists-and-engineers-push-the-boundaries-of-space-knowledge,-studying-the-stars,-the-solar-system-and-beyond.html\" target=\"_blank\">\n                                    Purdue scientists and engineers push the boundaries of space knowledge, studying the stars, the solar system and beyond                                <\/a>\n                            <\/li>\n                            <\/ul>\n\n<\/div>\n\n\n\n\n<p>Europa is a rocky moon, home to saltwater oceans twice the volume of Earth\u2019s, encased in a shell of ice. Scientists have long thought that Europa may be one of the best places in our solar system to look for nonterrestrial life. The likelihood and nature of that life, though, heavily depend on the thickness of its icy shell, something astronomers have not yet been able to measure.<\/p>\n\n\n\n<p>A team of planetary science experts including&nbsp;<a href=\"https:\/\/www.eaps.purdue.edu\/people\/profile\/johns477.html\" rel=\"noreferrer noopener\" target=\"_blank\">Brandon Johnson<\/a>, an associate professor, and&nbsp;<a href=\"https:\/\/www.eaps.purdue.edu\/people\/profile\/swakita.html\" rel=\"noreferrer noopener\" target=\"_blank\">Shigeru Wakita<\/a>, a research scientist, in the&nbsp;<a href=\"https:\/\/www.eaps.purdue.edu\/index.html\" rel=\"noreferrer noopener\" target=\"_blank\">Department of Earth, Atmospheric, and Planetary Sciences<\/a>&nbsp;in Purdue University\u2019s&nbsp;<a href=\"https:\/\/www.purdue.edu\/science\/\" rel=\"noreferrer noopener\" target=\"_blank\">College of Science<\/a>, announced in a new paper published in&nbsp;<a href=\"https:\/\/www.science.org\/doi\/10.1126\/sciadv.adj8455\" rel=\"noreferrer noopener\" target=\"_blank\">Science Advances<\/a>&nbsp;that Europa\u2019s ice shell is at least 20 kilometers thick.<\/p>\n\n\n\n<p>To reach their conclusion, the scientists studied large craters on Europa, running a variety of models to determine what combination of physical characteristics could have created such a surface structure.<\/p>\n\n\n\n<p>\u201cThis is the first work that has been done on this large crater on Europa,\u201d Wakita said. \u201cPrevious estimates showed a very thin ice layer over a thick ocean. But our research showed that there needs to be a thick layer \u2014 so thick that convection in the ice, which has previously been debated, is likely.\u201d<\/p>\n\n\n\n<p>Using data and images from the spacecraft Galileo, which studied Europa in 1998, Johnson analyzed the impact craters to decode truths about Europa\u2019s structure. An expert in planetary physics and colossal collisions, Johnson has studied almost every major planetary body in the solar system. Since no one is able to measure the thickness of Europa\u2019s ice shell directly, scientists are creatively using the evidence at hand:&nbsp;<a href=\"https:\/\/www.youtube.com\/embed\/Y9d-HvAoiBY\" rel=\"noreferrer noopener\" target=\"_blank\">the craters on Europa\u2019s icy surface (video of impact simulation)<\/a>.<\/p>\n\n\n\n<p>\u201cImpact cratering is the most ubiquitous surface process shaping planetary bodies,\u201d Johnson said. \u201cCraters are found on almost every solid body we\u2019ve ever seen. They are a major driver of change in planetary bodies. When an impact crater forms, it is essentially probing the subsurface structure of a planetary body. By understanding the sizes and shapes of craters on Europa and reproducing their formation with numerical simulations, we\u2019re able to infer information about how thick its ice shell is.\u201d&nbsp;<\/p>\n\n\n\n<p>Europa is a frozen world, but the ice shelters a rocky core. The icy surface, though, is not stagnant. Plate tectonics and convection currents in the oceans and the ice itself refresh the surface fairly frequently. This means the surface itself is only 50 million to 100 million years old \u2014 which sounds old to short-lived organisms like humans but is young as far as geological periods go.<\/p>\n\n\n\n<p>That smooth, young surface means that craters are clearly defined, easier to analyze and not very deep. Their impacts tell scientists more about the icy shell of the moon and the water ocean below, rather than conveying much information about its rocky heart.<\/p>\n\n\n\n<p>\u201cUnderstanding the thickness of the ice is vital to theorizing about possible life on Europa,\u201d Johnson said. \u201cHow thick the ice shell is controls what kind of processes are happening within it, and that is really important for understanding the exchange of material between the surface and the ocean. That is what will help us understand how all kinds of processes happen on Europa \u2014 and help us understand the possibility of life.\u201d<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">About Purdue University<\/h2>\n\n\n\n<p>Purdue University is a public research institution demonstrating excellence at scale. Ranked among top 10 public universities and with two colleges in the top four in the United States, Purdue discovers and disseminates knowledge with a quality and at a scale second to none. More than 105,000 students study at Purdue across modalities and locations, including nearly 50,000 in person on the West Lafayette campus. Committed to affordability and accessibility, Purdue\u2019s main campus has frozen tuition 13 years in a row. See how Purdue never stops in the persistent pursuit of the next giant leap \u2014 including its first comprehensive urban campus in Indianapolis, the new Mitchell E. Daniels, Jr. School of Business, and Purdue Computes \u2014 at&nbsp;<a href=\"https:\/\/www.purdue.edu\/president\/strategic-initiatives\" rel=\"noreferrer noopener\" target=\"_blank\">https:\/\/www.purdue.edu\/president\/strategic-initiatives<\/a>.&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>WEST LAFAYETTE, Ind. &mdash; Sometimes planetary physics is like being in a snowball fight. Most people, if handed an already-formed snowball, can use their experience and the feel of the ball to guess what kind of snow it is comprised<\/p>\n","protected":false},"author":7,"featured_media":3224,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[7,524],"tags":[],"department":[32],"source":[29],"purdue_today_topic":[66],"coauthors":[164],"class_list":["post-3222","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research-excellence","category-space","department-science","source-purdue-news","purdue_today_topic-research"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/posts\/3222","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/comments?post=3222"}],"version-history":[{"count":1,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/posts\/3222\/revisions"}],"predecessor-version":[{"id":3225,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/posts\/3222\/revisions\/3225"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/media\/3224"}],"wp:attachment":[{"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/media?parent=3222"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/categories?post=3222"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/tags?post=3222"},{"taxonomy":"department","embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/department?post=3222"},{"taxonomy":"source","embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/source?post=3222"},{"taxonomy":"purdue_today_topic","embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/purdue_today_topic?post=3222"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.purdue.edu\/newsroom\/wp-json\/wp\/v2\/coauthors?post=3222"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}