How Do We Define an 'Earth-Like' Planet?

We asked five scientists from Carnegie, each from a distinct field, to address this complex question.
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What is an 'Earth-like' Planet?

Today’s search for Earth-like planets is driven by our desire to understand our place in the universe and to answer the age-old question: Are we alone?

To tackle that question, we must first answer another: What exactly is an 'Earth-like' planet? 

We asked five scientists from different fields of study at the Carnegie Science Earth and Planets Laboratory to share their answers. 

It turns out that defining what makes a planet "Earth-like" isn't as straightforward as you might imagine, thanks to the highly interdisciplinary nature of this burgeoning area of research. From astronomers to geochemists, each field brings a unique lens to the study of exoplanets. 

At Carnegie Science, these research areas converge, fostering a collaborative environment that makes it the ideal place to tackle these complex, cross-disciplinary questions.

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On the Horizon

We can't physically journey to these distant worlds to gauge their Earth-likeness. Instead, scientists rely on remote observation techniques. By analyzing exoplanet atmospheres, we can uncover vital clues about their inner workings. For example, the presence of certain gases, like oxygen and methane, hint at life-sustaining processes, while atmospheric variations offer insights into a planet's dynamics.

However, with current telescope technology, Earth-sized planets are almost impossible to spot. In the future, the Giant Magellan Telescope will join the search, providing even sharper views from the Earth's surface, and greatly enhancing our ability to find Earth-like planets.

Learn more about the Giant Magellan arrow_forward