{"id":792324,"date":"2024-12-31T06:56:03","date_gmt":"2024-12-31T11:56:03","guid":{"rendered":"http:\/\/spaceweekly.com\/?p=792324"},"modified":"2024-12-31T06:56:03","modified_gmt":"2024-12-31T11:56:03","slug":"avalanches-icy-explosions-and-dunes","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=792324","title":{"rendered":"avalanches, icy explosions and dunes"},"content":{"rendered":"<p> <br \/>\n<\/p>\n<div>\n<p><iframe loading=\"lazy\" title=\"New Year, New Mars: Red Planet Gets Active as Spring Begins (Mars Report)\" width=\"1110\" height=\"624\" src=\"https:\/\/www.youtube.com\/embed\/_w9ZFDqXN38?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<ul>\n<li><strong>Spring on Mars brings explosive changes<\/strong>. As temperatures rise, the Martian northern hemisphere experiences dramatic events such as frost avalanches, carbon dioxide gas geysers, and winds reshaping polar ice caps and dunes.<\/li>\n<li><strong>Unlike Earth, Mars\u2019 ice sublimates directly into gas<\/strong>. The sublimation causes explosive activity like \u201cspiders\u201d (scour marks left after ice sublimation) and dark fans of material from gas geysers.<\/li>\n<li><strong>The Mars Reconnaissance Orbiter has been crucial<\/strong> for studying these dynamic processes for nearly 20 years. It captures unprecedented images and insights into the red planet\u2019s surface evolution.<\/li>\n<\/ul>\n<p>NASA\/JPL published this original article on December 20, 2024. Edits by EarthSky.<\/p>\n<h3>Mars is beginning another 687-day-long year<\/h3>\n<p>While we\u2019re celebrating New Year\u2019s Eve here on Earth, Mars scientists are ahead of the game: The red planet completed a trip around the sun on November 12, 2024, prompting a few researchers to raise a toast.<\/p>\n<p>But the Martian year, which is 687 Earth days, ends in a very different way in the planet\u2019s northern hemisphere than it does in Earth\u2019s northern hemisphere. While winter\u2019s kicking in here, spring is starting there. That means temperatures are rising and ice is thinning, leading to frost avalanches crashing down cliffsides, carbon dioxide gas exploding from the ground and powerful winds helping reshape the north pole.<\/p>\n<p>Serina Diniega, who studies planetary surfaces at NASA\u2019s Jet Propulsion Laboratory in Southern California, said:<\/p>\n<blockquote>\n<p>Springtime on Earth has lots of trickling as water ice gradually melts. But on Mars, everything happens with a bang.<\/p>\n<\/blockquote>\n<p>The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Get yours today!<\/p>\n<h3>Springtime literally explodes on the red planet<\/h3>\n<p>Mars\u2019 wispy atmosphere doesn\u2019t allow liquids to pool on the surface as on Earth. Instead of melting, ice sublimates, turning directly into a gas. The sudden transition in spring means a lot of violent changes as both water ice and carbon dioxide ice \u2013 dry ice, which is much more plentiful on Mars than frozen water \u2013 weaken and break.<\/p>\n<p>Diniega said:<\/p>\n<blockquote>\n<p>You get lots of cracks and explosions instead of melting. I imagine it gets really noisy.<\/p>\n<\/blockquote>\n<p>Using the cameras and other sensors aboard NASA\u2019s Mars Reconnaissance Orbiter (MRO), which launched in 2005, scientists study all this activity to improve their understanding of the forces shaping the dynamic Martian surface. Here\u2019s some of what they track.<\/p>\n<figure id=\"attachment_496710\" aria-describedby=\"caption-attachment-496710\" style=\"width: 800px\" class=\"wp-caption alignnone\"><figcaption id=\"caption-attachment-496710\" class=\"wp-caption-text\">Martian spring involves lots of cracking ice, which led to this 66-foot-wide (20-meter-wide) chunk of carbon dioxide frost captured in freefall by the HiRISE camera aboard NASA\u2019s Mars Reconnaissance Orbiter (MRO) in 2015. Image via NASA\/ JPL-Caltech\/ University of Arizona.<\/figcaption><\/figure>\n<h3>Frost avalanches caught in action on Mars<\/h3>\n<p>In 2015, MRO\u2019s High-Resolution Imaging Science Experiment (HiRISE) camera captured a 66-foot-wide (20-meter-wide) chunk of carbon dioxide frost in freefall. Chance observations like this are reminders of just how different Mars is from Earth, Diniega said, especially in springtime, when these surface changes are most noticeable.<\/p>\n<p>Diniega said:<\/p>\n<blockquote>\n<p>We\u2019re lucky we\u2019ve had a spacecraft like MRO observing Mars for as long as it has. Watching for almost 20 years has let us catch dramatic moments like these avalanches.<\/p>\n<\/blockquote>\n<figure id=\"attachment_496712\" aria-describedby=\"caption-attachment-496712\" style=\"width: 800px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/earthsky.org\/upl\/2024\/12\/Gas-geysers-on-Mars-scaled-e1734727328965.jpg\" alt=\"Arrowhead or fan shaped black marks darker at the point, fading to gray, on a red terrain.\" width=\"800\" height=\"500\" class=\"size-full wp-image-496712\"\/><figcaption id=\"caption-attachment-496712\" class=\"wp-caption-text\">As light shines through carbon dioxide ice on Mars, it heats up its bottom layers, which, rather than melting into a liquid, turn into gas. The builtup gas eventually results in explosive geysers that toss dark fans of debris onto the surface. Image via NASA\/ JPL-Caltech\/ University of Arizona.<\/figcaption><\/figure>\n<h3>Gas geysers blast \u2018spiders\u2019 on Martian southern hemisphere<\/h3>\n<p>Diniega has relied on HiRISE to study another quirk of Martian springtime: gas geysers that blast out of the surface, throwing out dark fans of sand and dust. These explosive jets form due to energetic sublimation of carbon dioxide ice. As sunlight shines through the ice, its bottom layers turn to gas, building pressure until it bursts into the air, creating those dark fans of material.<\/p>\n<p>But to see the best examples of the newest fans, researchers will have to wait until December 2025, when spring starts in the southern hemisphere. There, the fans are bigger and more clearly defined.<\/p>\n<p>Another difference between ice-related action in the two hemispheres: Once all the ice around some northern geysers has sublimated in summer, what\u2019s left behind in the dirt are scour marks that, from space, look like giant spider legs. Researchers recently re-created this process in a JPL lab.<\/p>\n<figure id=\"attachment_496713\" aria-describedby=\"caption-attachment-496713\" style=\"width: 800px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/earthsky.org\/upl\/2024\/12\/Spider-Markings-on-Mars-e1734727487177.jpg\" alt=\"Dark, irregular radial lines spread from several central points on a dirt background.\" width=\"800\" height=\"450\" class=\"size-full wp-image-496713\"\/><figcaption id=\"caption-attachment-496713\" class=\"wp-caption-text\">Sometimes, after carbon dioxide geysers have erupted from ice-covered areas on Mars, they leave scour marks on the surface. When the ice is all gone by summer, these long scour marks look like the legs of giant spiders. Image via NASA\/ JPL-Caltech\/ University of Arizona.<\/figcaption><\/figure>\n<h3>Powerful winds leave enormous scars on Mars\u2019 ice cap<\/h3>\n<p>For Isaac Smith of Toronto\u2019s York University, one of the most fascinating subjects in springtime is the Texas-size ice cap at Mars\u2019 north pole. Etched into the icy dome are swirling troughs, revealing traces of the red surface below. The effect is like a swirl of milk in a caf\u00e9 latte.<\/p>\n<p>Noting that some are as long as California, Smith said:<\/p>\n<blockquote>\n<p>These things are enormous. You can find similar troughs in Antarctica but nothing at this scale.<\/p>\n<\/blockquote>\n<p>Fast, warm wind has carved the spiral shapes over eons, and the troughs act as channels for springtime wind gusts that become more powerful as ice at the north pole starts to thaw. Just like the Santa Ana winds in Southern California or the Chinook winds in the Rocky Mountains, these gusts pick up speed and temperature as they ride down the troughs, in what\u2019s called an adiabatic process.<\/p>\n<figure id=\"attachment_496715\" aria-describedby=\"caption-attachment-496715\" style=\"width: 800px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/earthsky.org\/upl\/2024\/12\/Mars-Polar-Ice-Cap-e1735643155124.jpg\" alt=\"Large white area, with distinct, dark spiral streaks in it, on a reddish region of a planet.\" width=\"800\" height=\"640\" class=\"size-full wp-image-496715\"\/><figcaption id=\"caption-attachment-496715\" class=\"wp-caption-text\">As temperatures rise, powerful winds kick up that carve deep troughs into the ice cap of Mars\u2019 north pole. Some of these troughs are as long as California. And they give the Martian north pole its trademark swirls. NASA\u2019s now-inactive Mars Global Surveyor captured this image. Image via NASA\/ JPL-Caltech\/ MSSS.<\/figcaption><\/figure>\n<h3>Sand dunes wander across the Martian landscape<\/h3>\n<p>The winds that carve the north pole\u2019s troughs also reshape Mars\u2019 sand dunes, causing sand to pile up on one side while removing sand from the other side. Over time, the process causes dunes to migrate, just as it does with dunes on Earth.<\/p>\n<p>Last September, Smith coauthored a paper detailing how carbon dioxide frost settles on top of polar sand dunes during winter, freezing them in place. When the frost all thaws away in the spring, the dunes begin migrating again.<\/p>\n<p>Each northern spring is a little different, with variations leading to ice sublimating faster or slower, controlling the pace of all these phenomena on the surface. And these strange phenomena are just part of the seasonal changes on Mars: the southern hemisphere has its own unique activity.<\/p>\n<figure id=\"attachment_496716\" aria-describedby=\"caption-attachment-496716\" style=\"width: 800px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/earthsky.org\/upl\/2024\/12\/Wandering-Dunes-of-Mars-e1735643223943.jpg\" alt=\"Dark, raised kidney-shaped masses spaced on a crackled light background.\" width=\"800\" height=\"600\" class=\"size-full wp-image-496716\"\/><figcaption id=\"caption-attachment-496716\" class=\"wp-caption-text\">Surrounded by frost, these Martian dunes are in Mars\u2019 northern hemisphere. NASA\u2019s Mars Reconnaissance Orbiter used its HiRISE camera to capture them from above on September 8, 2022. Image via NASA\/ JPL-Caltech\/ University of Arizona.<\/figcaption><\/figure>\n<p>Bottom line: A new and explosive year began on Mars on November 14, 2024. NASA and its partners are tracking the season\u2019s strange and unique features.<\/p>\n<p>Read more: Mars is racing toward opposition in January 2025: Start watching now!<\/p>\n<p><span class=\"cp-load-after-post\"\/><\/div>\n<div>\n<div class=\"post-author\">\n<h4>EarthSky Voices<\/h4>\n<p>                    View Articles\n                  <\/p><\/div>\n<div class=\"post-tags\">\n<h6 data-udy-fe=\"text_7c58270d\">About the Author:<\/h6>\n<p>Members of the EarthSky community &#8211; including scientists, as well as science and nature writers from across the globe &#8211; weigh in on what&#8217;s important to them.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<p><br \/>\n<br \/><a href=\"https:\/\/earthsky.org\/space\/mars-starts-a-new-year-avalanches-icy-explosions-and-dunes\/?rand=772280\">Source link <\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Spring on Mars brings explosive changes. As temperatures rise, the Martian northern hemisphere experiences dramatic events such as frost avalanches, carbon dioxide gas geysers, and winds reshaping polar ice caps&hellip; <\/p>\n","protected":false},"author":1,"featured_media":792325,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[],"class_list":["post-792324","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earth-sky"],"_links":{"self":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts\/792324","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=792324"}],"version-history":[{"count":0,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts\/792324\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/media\/792325"}],"wp:attachment":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=792324"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=792324"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=792324"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}