The Best Strategies To Identify A Habitable Planet

Of all the towering and imposing dilemmas that plague us, perhaps the most prominent is that of understanding our place in the universe. We often find ourselves looking up at the stars and asking some seemingly inscrutable questions. Are we alone? What else is out there? Who else is out there? These interstellar quandaries serve as the basis for many of our undertakings in space, and our burning desire to understand the universe manifests itself in the biggest goal of them all -- finding extraterrestrial life. NASA stands as the prime agent of these exploratory efforts, and theyve since unveiled a trove of thousands of exoplanets that they believe could harbor life. That being said, the process of actually discerning a planets habitability is severely under-discussed, and I thus hope to explore some of the strategies used by scientists that ultimately underscore and enable our search for life beyond Earth.

Following what NASA called a gold-rush of exoplanet discovery, we find ourselves facing the most daunting question of all which of the known exoplanets are optimal candidates for life? Interestingly, scientists can never fully determine if a planet is truly habitable doing so would require direct observation, and even the most advanced optical measures devised wouldnt be able to afford such needs. Thus, in our journey to uncover life on other worlds, we must use tools already at our disposal and knowledge of interstellar processes, beginning with direct images.

Now you may think that taking a picture of Earth or a similar planet from space is a waste of time after all, ascertaining the potential for life from a single collection of pixels sounds bizarre. However, scientists have had much success using the technique for Earth, and hope to apply similar principles for worlds beyond our own. Using NASAs Polychromatic Imaging Camera, researchers at UC Riverside take high-resolution images of Earth, and degrade the images down to a 3x3 grid of grey-scale pixels. By taking images every hour and examining how these pixels change, scientists can determine when land is mostly in view compared with water, as well as the planets rotation rate, incident light reflection, and seasonal variation. These metrics directly influence Earths potential for life, and scientists hope to use the exact same technique when visiting other planets.

In addition to understanding the quantities and circumstances that enable life on exoplanets, the ability to quickly eliminate worlds as inhabitable is of tantamount importance. A common elucidation of this point comes with a description of Venus; though incredibly similar to Earth in size and shape, Venus boasts a surface temperature of nearly 900 degrees Fahrenheit, with over 90 times the pressure of our world. The Riverside researchers clarify that if they can treat Venus as the unlivable counterpart to Earth, they can use planetary insolation the amount of light a planet receives from its host star, and the main quantity that makes Venus such an undesirable hell-hole to quickly cross uninhabitable planets off their list, as well as determine how often developing worlds end up in such crappy shape.

The final and, in my opinion, most exciting strategy is that of modeling the stellar-planetary processes that govern and permit life in space. For instance, the magnetic field that cradles Earth shields us from invasive solar wind and debris. Similarly, scientists use computational modeling to drape an Earth-like magnetic field over exoplanets, and examine how well its atmosphere would be protected. In essence, a worlds sun needs to produce enough penetrating radiation that would sustain life, but exercise restraint in storm and solar activity that could ravage a planets atmosphere, endangering the prospect of liquid water.

By using X-Ray telescopes, scientists can map the amount of radiation produced by a host star, and simulate how the atmosphere of orbiting exoplanets responds to such activity. We can then use computational models to place Earth, with the same atmosphere, magnetic field, and gravitational constants, in the exoplanets orbit to compare the results. These studies would offer us incredible insight into not only whether the exoplanet could sustain life, but also if a known habitable world would survive in the orbit of the host star.

Ultimately, such strategies underscore a committed effort to finding extraterrestrial life, and whether or not they turn out to be effective, we should nonetheless pay our respects. We still find numerous parts of our own world inexplicable, and yet we have mounted a brilliant and unrelenting effort to divulge the mysteries of others. This interdisciplinary blend of science, technology, design, and sheer passion collectively forms one of humanitys greatest undertakings, and its such an effort I wish to recognize regardless of what happens.