{"id":6267,"date":"2023-07-26T16:23:00","date_gmt":"2023-07-26T16:23:00","guid":{"rendered":"https:\/\/new.www.purdue.edu\/newsroom\/?p=6267"},"modified":"2024-08-06T13:24:36","modified_gmt":"2024-08-06T17:24:36","slug":"growing-clouds-in-a-lab-to-study-the-science-of-far-away-skies","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/newsroom\/2023\/Q3\/growing-clouds-in-a-lab-to-study-the-science-of-far-away-skies","title":{"rendered":"Growing clouds in a lab to study the science of far-away skies"},"content":{"rendered":"
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Note to journalists<\/a><\/div>\n <\/div>\n<\/div>\n\n\n\n
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WEST LAFAYETTE, Ind. —<\/p> \n

Alexandria Johnson<\/a> does hard science on the most nebulous of subjects: clouds. As an atmospheric scientist and assistant professor of practice in Purdue University\u2019s College of Science<\/a>, she studies clouds wherever they are: in her lab, on Earth, throughout the solar system and into the galaxy.<\/p>\n<\/div>\n\n\n

\u201cThe coolest thing about my research is that I can see clouds every day,\u201d Johnson said. \u201cI can look up into our own atmosphere and watch them change and evolve. Then I can take that knowledge and apply it to other planetary bodies, both within and outside our solar system.\u201d<\/p>\n\n\n\n

The science of clouds covers a lot of ground. Her research shines light into topics ranging from the rainfall and microplastic precipitation in Indiana to the climates of moons and planets far outside the realm of human experience.<\/p>\n\n\n\n

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Studying clouds in the wild can be challenging. Atmospheric scientist Alexandria Johnson uses lasers and controlled environments to study lab-grown versions: particles that behave like miniature clouds and help her explore the physics and microphysics of clouds. (Purdue University\/John Underwood)<\/figcaption><\/figure>\n\n\n\n

Clouds in a bottle and a tempest in a teacup <\/strong><\/h2>\n\n\n\n

Studying clouds in their natural environments can be complex and subject to the variations of climate, weather and observation devices. Johnson\u2019s solution is to create her own homegrown clouds to study in her lab in the Department of Earth, Atmospheric, and Planetary Sciences<\/a>. She strips the systems down to their basics to get a clear understanding on how the particles that make up clouds form, develop and interact with their environment. Nothing in her lab actually looks like a cloud; there are no mists swirling picturesquely in glass bottles. It\u2019s mostly lasers and big black boxes. But the behavior of these lab-based cloud particles mimics the behavior of cloud particles in massive sky-sweeping clouds, only in miniature.<\/p>\n\n\n\n

\u201cOf course, we don\u2019t grow them at quite the same scale you see in an atmosphere,\u201d Johnson said. \u201cInstead, we can take one particle that is representative of a cloud, pump in different gases, and change the temperature and pressure of the system. We then watch as that particle grows, shrinks or changes phase with time, which are processes that happen in clouds everywhere.\u201d<\/p>\n\n\n\n

Clouds on Earth don\u2019t often form without the aid of a nuclei, or a particle, and in some cases what would be considered a nuclei on Earth may be an exotic cloud elsewhere. The particles in Johnson\u2019s lab, like all particles, have a charge. Johnson and her team use an electric field to levitate and contain the individual particles so that they can\u2019t move around. These particles are then stable for extended periods of time, which enables long-term research experiments, where the pressure, temperature, electric field and laser illumination may be tweaked, and observations recorded. Other methods build upon these to allow the team to look at groups of particles and observe how they scatter and polarize light.<\/p>\n\n\n\n

Using methods like these, Johnson can study how clouds form and what different cloud particle shapes and compositions can reveal, and she is able to understand the conditions that lead to different cloud types and behaviors. Like aeronautical engineers using a wind tunnel to observe how currents move around structures, Johnson uses these particles to understand the microphysics that underpin vast and complex systems.<\/p>\n\n\n\n

Many scientists \u2013 climatologists, meteorologists and planetary scientists, to name a few \u2013 study clouds as part of their broader research. But Johnson is one of the few who studies the particular physics of clouds in the laboratory.<\/p>\n\n\n\n

\u201cThere are not many of us who dig into the microphysics of how clouds form,\u201d Johnson said. \u201cAnyone who studies the atmosphere has a general sense of knowledge about clouds. But none of those systems work without the physics. We have to understand the microphysics to truly grasp the complexities and implications.\u201d<\/p>\n\n\n\n

Every cloud has a silver lining<\/strong><\/h2>\n\n\n\n

It\u2019s a long-running joke that the nights of notable astronomical events on Earth seem to be almost supernaturally disposed to be cloudy. That is true of other planets, too.<\/p>\n\n\n\n

Using enormous, advanced, vastly powerful telescopes, astronomers can peer through miles and light-years of space just to find clouds blocking their view of the planet itself. Rather than the planet\u2019s surface, they can only perceive the opaque atmosphere that enswathes it.<\/p>\n\n\n\n

Every planetary body in the solar system that has a dense atmosphere, and many outside of it, has clouds in that atmosphere. Even bodies with thin, wispy or intermittent atmospheres \u2013 like Pluto \u2013 have particulates hanging in the atmosphere that, while not true clouds, are a haze of particles and share many of clouds\u2019 properties.<\/p>\n\n\n\n

\u201cClouds are a ubiquitous feature of planetary atmospheres,\u201d Johnson said. \u201cThis is something we\u2019ve seen from our own solar system, and when we look at exoplanet atmospheres, it\u2019s no surprise that we find clouds there too. Unfortunately, they tend to block our view of the atmosphere that is below.\u201d<\/p>\n\n\n\n

Scientists have been able to send probes and rovers to close planetary neighbors, including Venus and Mars. But for bodies that are farther away, including exoplanets \u2013 planets in other star systems entirely \u2013 scientists must come up with clever ways to conduct science.<\/p>\n\n\n\n

\u201cThe astronomers find the clouds to be an annoyance. They get in the way of the data they want, whether that\u2019s learning about the surface of the planet or its atmospheric composition,\u201d Johnson said. \u201cWe see it a little differently. Yes, they\u2019re there. We can\u2019t get rid of them. So let\u2019s use our understanding of clouds on Earth and planetary atmospheres of our solar system to learn about these things that we can\u2019t observe in exoplanets.\u201d<\/p>\n\n\n\n

Most of the planets Johnson studies are \u201ccool\u201d planets. While Earth seems balmy (with planetary temperature averages around 60 degrees Fahrenheit), it is actually chilly by planetary standards, when contrasted to large, gas giants orbiting close to their stars like hot Jupiters. <\/p>\n\n\n\n

Johnson and her team accumulate information about planetary bodies in Earth\u2019s solar system or exoplanets. Astronomers can collect spectrographic data to analyze the chemical compounds that make up the atmosphere and use mathematical models, observations and gravitation studies to determine a planet\u2019s mass, speed and orbit. Combining that information with insights from her laboratory studies, Johnson can help astronomers determine what a planet\u2019s atmosphere might be like and extrapolate its chance for hosting life.<\/p>\n\n\n\n

\u201cOur big questions are when, where and why do clouds form in these atmospheres?\u201d Johnson said. \u201cIf we want to understand these enshrouded exoplanets, we need to understand the clouds. That understanding gives us insights into the atmospheric chemistry at work, atmospheric circulation and the climate. In a way we ground-truth astronomical observations.\u201d<\/p>\n\n\n\n

Both sides now<\/strong><\/h2>\n\n\n\n

Johnson is also looking up at the clouds from below, a little closer to home. In a current study, she is examining the role microplastics play in cloud formation. Microplastics pollution, which has been found just about everywhere, including large bodies of water like the Great Lakes, may form a part of clouds or be scavenged by precipitation, then shower the landscape in rainstorms and snowfall. Those microplastics have dire implications for ecosystem health, human health and agriculture.<\/p>\n\n\n\n

Understanding how they become attached to clouds, move through weather systems and impact the landscape when deposited can help Johnson and her team protect life on Earth, just as they explore the possibility of livable conditions on other planets.<\/p>\n\n\n\n

\u201cIt\u2019s the same physics,\u201d Johnson said. \u201cIt\u2019s the same processes, all throughout the universe, and it brings me a huge amount of wonder and joy. As an undergraduate physics major, I chose a senior research project studying how water droplets froze under varying conditions. I literally watched a droplet freeze hundreds of times to study the process and was entranced. I said, \u2018This is what I want to do with my life. This is amazing. I want to study clouds.\u2019\u201d<\/p>\n\n\n\n

About Purdue University<\/strong><\/h2>\n\n\n\n

Purdue University is a top public research institution developing practical solutions to today\u2019s toughest challenges. Ranked in each of the last five years as one of the 10 Most Innovative universities in the United States by U.S. News & World Report, Purdue delivers world-changing research and out-of-this-world discovery. Committed to hands-on and online, real-world learning, Purdue offers a transformative education to all. Committed to affordability and accessibility, Purdue has frozen tuition and most fees at 2012-13 levels, enabling more students than ever to graduate debt-free. See how Purdue never stops in the persistent pursuit of the next giant leap at https:\/\/stories.purdue.edu<\/strong><\/a>. <\/p>\n\n\n

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\n Writer\/Media contact:<\/strong>\u00a0Brittany Steff,\u00a0bsteff@purdue.edu<\/a>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0
Source:<\/strong>\u00a0Alexandria Johnson,\u00a0avjohns@purdue.edu<\/a> <\/p>\n <\/div>\n

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Note to journalists:<\/p>\n

\n A\u00a0video link<\/a>\u00a0is available to media who have an Associated Press subscription. <\/p>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

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