{"id":142750,"date":"2025-11-20T02:31:13","date_gmt":"2025-11-20T02:31:13","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/142750\/"},"modified":"2025-11-20T02:31:13","modified_gmt":"2025-11-20T02:31:13","slug":"exoplanet-atmospheres-are-the-next-clue-to-finding-life-on-planets-orbiting-distant-stars","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/142750\/","title":{"rendered":"Exoplanet atmospheres are the next clue to finding life on planets orbiting distant stars"},"content":{"rendered":"

When astronomers search for planets that could host liquid water on their surface, they start by looking at a star\u2019s habitable zone<\/a>. Water is a key ingredient for life<\/a>, and on a planet too close to its star, water on its surface may \u201cboil\u201d; too far, and it could freeze. This zone marks the region in between. <\/p>\n

But being in this sweet spot<\/a> doesn\u2019t automatically mean a planet is hospitable to life. Other factors, like whether a planet is geologically active or has processes that regulate gases in its atmosphere, play a role. <\/p>\n

The habitable zone provides a useful guide to search for signs of life on exoplanets \u2013 planets outside our solar system orbiting other stars. But what\u2019s in these planets\u2019 atmospheres holds the next clue about whether liquid water \u2014 and possibly life \u2014 exists beyond Earth. <\/p>\n

On Earth, the greenhouse effect<\/a>, caused by gases like carbon dioxide and water vapor, keeps the planet warm enough for liquid water and life as we know it. Without an atmosphere, Earth\u2019s surface temperature would average around zero degrees Fahrenheit<\/a> (minus 18 degrees Celsius), far below the freezing point of water. <\/p>\n

The boundaries of the habitable zone are defined by how much of a \u201cgreenhouse effect\u201d is necessary to maintain the surface temperatures that allow for liquid water to persist. It\u2019s a balance between sunlight and atmospheric warming.<\/p>\n

Many planetary scientists, including me<\/a>, are seeking to understand if the processes responsible for regulating Earth\u2019s climate are operating on other habitable zone worlds. We use what we know about Earth\u2019s geology and climate to predict how these processes might appear elsewhere, which is where my geoscience expertise comes in. <\/p>\n

\"A<\/p>\n

Picturing the habitable zone of a solar system analog, with Venus- and Mars-like planets outside of the \u2018just right\u2019 temperature zone.
\n NASA<\/a><\/p>\n

Why the habitable zone?<\/p>\n

The habitable zone is a simple and powerful idea, and for good reason. It provides a starting point, directing astronomers to where they might expect to find planets with liquid water, without needing to know every detail about the planet\u2019s atmosphere or history. <\/p>\n

Its definition is partially informed by what scientists know about Earth\u2019s rocky neighbors. Mars, which lies just outside the outer edge of the habitable zone, shows clear evidence of ancient rivers and lakes<\/a> where liquid water once flowed. <\/p>\n

Similarly, Venus is currently too close to the Sun to be within the habitable zone. Yet, some geochemical evidence<\/a> and modeling studies<\/a> suggest Venus may have had water in its past, though how much and for how long remains uncertain. <\/p>\n

These examples show that while the habitable zone is not a perfect predictor of habitability, it provides a useful starting point. <\/p>\n

Planetary processes can inform habitability<\/p>\n

What the habitable zone doesn\u2019t do is determine whether a planet can sustain habitable conditions over long periods of time. On Earth, a stable climate allowed life to emerge and persist<\/a>. Liquid water could remain on the surface, giving slow chemical reactions enough time<\/a> to build the molecules of life and let early ecosystems develop resilience<\/a> to change, which reinforced habitability. <\/p>\n

Life emerged on Earth, but continued to reshape the environments it evolved in<\/a>, making them more conducive to life. <\/p>\n

This stability likely unfolded over hundreds of millions of years, as the planet\u2019s surface, oceans and atmosphere worked together as part of a slow but powerful system<\/a> to regulate Earth\u2019s temperature. <\/p>\n

A key part of this system is how Earth recycles inorganic carbon<\/a> between the atmosphere, surface and oceans over the course of millions of years. Inorganic carbon refers to carbon bound in atmospheric gases, dissolved in seawater or locked in minerals, rather than biological material. This part of the carbon cycle acts like a natural thermostat<\/a>. When volcanoes release carbon dioxide into the atmosphere, the carbon dioxide molecules trap heat and warm the planet. As temperatures rise, rain and weathering draw carbon out of the air and store it in rocks and oceans. <\/p>\n

If the planet cools, this process slows down, allowing carbon dioxide, a warming greenhouse gas<\/a>, to build up in the atmosphere again. This part of the carbon cycle has helped Earth recover from past ice ages and avoid runaway warming. <\/p>\n

Even as the Sun has gradually brightened, this cycle has contributed to keeping temperatures on Earth within a range where liquid water and life can persist for long spans of time. <\/p>\n

Now, scientists are asking whether similar geological processes might operate on other planets, and if so, how they might detect them. For example, if researchers could observe enough rocky planets in their stars\u2019 habitable zones, they could look for a pattern<\/a> connecting the amount of sunlight a planet receives and how much carbon dioxide is in its atmosphere. Finding such a pattern may hint that the same kind of carbon-cycling process could be operating elsewhere. <\/p>\n

The mix of gases in a planet\u2019s atmosphere is shaped by what\u2019s happening on or below its surface. One study<\/a> shows that measuring atmospheric carbon dioxide in a number of rocky planets could reveal whether their surfaces are broken into a number of moving plates, like Earth\u2019s, or if their crusts are more rigid. On Earth, these shifting plates<\/a> drive volcanism and rock weathering, which are key to carbon cycling.<\/p>\n

\"A<\/p>\n

Simulation of what space telescopes, like the Habitable Worlds Observatory, will capture when looking at distant solar systems.
\n STScI, NASA GSFC<\/a><\/p>\n

Keeping an eye on distant atmospheres<\/p>\n

The next step will be toward gaining a population-level perspective<\/a> of planets in their stars\u2019 habitable zones. By analyzing atmospheric data from many rocky planets, researchers can look for trends that reveal the influence of underlying planetary processes, such as the carbon cycle. <\/p>\n

Scientists could then compare these patterns with a planet\u2019s position in the habitable zone. Doing so would allow them to test whether the zone accurately predicts where habitable conditions are possible, or whether some planets maintain conditions suitable for liquid water beyond the zone\u2019s edges. <\/p>\n

This kind of approach is especially important given the diversity of exoplanets<\/a>. Many exoplanets fall into categories that don\u2019t exist in our solar system<\/a> \u2014 such as super Earths<\/a> and mini Neptunes<\/a>. Others orbit stars smaller and cooler than the Sun<\/a>. <\/p>\n

The datasets needed to explore and understand this diversity are just on the horizon. NASA\u2019s upcoming Habitable Worlds Observatory<\/a> will be the first space telescope designed specifically to search for signs of habitability and life on planets orbiting other stars. It will directly image Earth-sized planets around Sun-like stars to study their atmospheres in detail. <\/p>\n

NASA\u2019s planned Habitable Worlds Observatory will look for exoplanets that could potentially host life.<\/p>\n

Instruments on the observatory will analyze starlight passing through these atmospheres to detect gases like carbon dioxide, methane, water vapor and oxygen. As starlight filters through a planet\u2019s atmosphere, different molecules absorb specific wavelengths of light, leaving behind a chemical fingerprint<\/a> that reveals which gases are present. These compounds offer insight into the processes shaping these worlds. <\/p>\n

The Habitable Worlds Observatory is under active scientific and engineering development, with a potential launch targeted for the 2040s<\/a>. Combined with today\u2019s telescopes, which are increasingly capable of observing atmospheres of Earth-sized worlds, scientists may soon be able to determine whether the same planetary processes that regulate Earth\u2019s climate are common throughout the galaxy, or uniquely our own.<\/p>\n","protected":false},"excerpt":{"rendered":"When astronomers search for planets that could host liquid water on their surface, they start by looking at…\n","protected":false},"author":2,"featured_media":142751,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[85,46,141,145],"class_list":{"0":"post-142750","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-il","9":"tag-israel","10":"tag-science","11":"tag-space"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/142750","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=142750"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/142750\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/142751"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=142750"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=142750"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=142750"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}