{"id":9513,"date":"2025-01-28T13:26:46","date_gmt":"2025-01-28T18:26:46","guid":{"rendered":"https:\/\/spaceandplanetarynewswire.com\/?p=9513"},"modified":"2025-01-28T13:26:46","modified_gmt":"2025-01-28T18:26:46","slug":"explaining-persistent-hydrogen-in-mars-atmosphere","status":"publish","type":"post","link":"https:\/\/spaceandplanetarynewswire.com\/?p=9513","title":{"rendered":"Explaining Persistent Hydrogen in Mars\u2019 Atmosphere"},"content":{"rendered":"
An artist’s impression of how Mars may have looked about 4 billion years ago. Credit: ESO\/M. Kornmesser\/N. Risinger<\/figcaption><\/figure>\n

New insight into Red Planet\u2019s hot again, cold again history<\/em><\/strong><\/p>\n

The fact that the cold, dry Mars of today had flowing rivers and lakes several billion years ago has puzzled scientists for decades. Now, Harvard researchers think they have a good explanation for a warmer, wetter ancient Mars.    <\/p>\n

Building on prior theories describing the Mars of yore as a hot again, cold again place, a team led by researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences<\/a> (SEAS) have determined the chemical mechanisms by which ancient Mars was able to sustain enough warmth in its early days to host water, and possibly life.  <\/p>\n

\u201cIt\u2019s been such a puzzle that there was liquid water on Mars, because Mars is further from the sun, and also, the sun was fainter early on,\u201d said Danica Adams<\/a>, NASA Sagan Postdoctoral Fellow and lead author of the new paper in Nature Geoscience<\/a><\/em>.<\/p>\n

Hydrogen was previously theorized as the magic ingredient, mixed with carbon dioxide in the Martian atmosphere to trigger episodes of greenhouse warming. But the lifetime of atmospheric hydrogen is short, so a more detailed analysis was required.<\/p>\n

Now, Adams; Robin Wordsworth<\/a>, the Gordon McKay Professor of Environmental Science and Engineering at SEAS; and team have performed photochemical modeling \u2013 similar to methods used today to track air pollutants \u2013 to fill in details of the early Martian atmosphere\u2019s relationship to hydrogen, and how that relationship changed over time.<\/p>\n

\u201cEarly Mars is a lost world, but it can be reconstructed in great detail if we ask the right questions,\u201d Wordsworth said. \u201cThis study synthesizes atmospheric chemistry and climate for the first time, to make some striking new predictions \u2013 which are testable once we bring Mars rocks back to Earth.\u201d<\/p>\n

Adams modified a model called KINETICS to simulate how a combination of hydrogen and other gases reacting with both the ground and the air controlled the early Martian climate.<\/p>\n

She found that during Mars\u2019 Noachian and Hesperian periods, between 4 and 3 billion years ago, Mars experienced episodic warm spells over about 40 million years, with each event lasting 100,000 or more years. These estimates are consistent with geologic features on Mars today. The warm, wet periods were driven by crustal hydration, or water being lost to the ground, which supplied enough hydrogen to build up in the atmosphere over millions of years.<\/p>\n

During the fluctuations between warm and cold climates, the chemistry of Mars\u2019 atmosphere was also fluctuating. CO2 is constantly hit by sunlight and converted to CO. In warm periods, the CO could recycle back into CO2, making CO2 and hydrogen dominant. But if it was cold for long enough, the recycling would slow down, build up CO, and bring about a more reduced state, a.k.a. less oxygen. The redox states of the atmosphere thus changed dramatically over time.<\/p>\n

\u201cWe\u2019ve identified time scales for all of these alternations,\u201d Adams said. \u201cAnd we\u2019ve described all the pieces in the same photochemical model.\u201d<\/p>\n

The modeling work lends potential new insight into conditions that supported prebiotic chemistry \u2013 the underpinnings of later life as we know it \u2013 during warm periods, and challenges for the persistence of that life during intervals of cold and oxidation. Adams and others are starting to work on finding evidence of those alternations using isotope chemical modeling, and they plan to compare those results to rocks from the upcoming Mars Sample Return<\/a> mission.<\/p>\n

NASA\u2019s Perseverance Mars rover used one of its navigation cameras to take this image of flat terrain in Jezero Crater, a possible future site for a Mars Sample Return lander. Credit: NASA\/JPL-Caltech<\/figcaption><\/figure>\n

Because Mars lacks plate tectonics, unlike Earth, the surface seen today is similar to that of long ago, making its history of lakes and rivers that much more intriguing. \u201cIt makes a really great case study for how planets can evolve over time,\u201d Adams said.<\/p>\n

Adams started the work as a Ph.D. student at California Institute of Technology, which hosts the photochemical model she used. The study was supported by NASA and Jet Propulsion Laboratory.<\/p>\n","protected":false},"excerpt":{"rendered":"

New insight into Red Planet\u2019s hot again, cold again history The fact that the cold, dry Mars of today had flowing rivers and lakes several billion years ago has puzzled scientists for decades. Now, Harvard researchers think they have a good explanation for a warmer, wetter ancient Mars.     Building on prior theories describing the…<\/p>\n","protected":false},"author":71,"featured_media":9515,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"fifu_image_url":"https:\/\/cdn.eso.org\/images\/publicationjpg\/eso1509a.jpg","fifu_image_alt":"","footnotes":""},"categories":[207],"tags":[],"class_list":["post-9513","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research"],"_links":{"self":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/9513","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/users\/71"}],"replies":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9513"}],"version-history":[{"count":1,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/9513\/revisions"}],"predecessor-version":[{"id":9516,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/posts\/9513\/revisions\/9516"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=\/wp\/v2\/media\/9515"}],"wp:attachment":[{"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9513"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9513"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spaceandplanetarynewswire.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9513"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}