Exoplanets: Not a Small World After All

Audience: Middle School Students

Did you know? To date, more than 5,000 exoplanets are confirmed to exist. Photo by NASA Hubble Space Telescope from Unsplash.

When I was in elementary school, I didn’t know about the existence of exoplanets. In class, I watched animated videos and read vibrant picture books that depicted ten celestial bodies: the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. There was “space,” colored in a sedate grey-black color, and there were the nine planets, illustrated in various neon hues. That was all. There was no deep space, black holes, or dark matter. Maybe there was a tiny bit of blank space extending slightly beyond Neptune and Pluto, but other than that, the universe seemed to end at the one-inch page margin. Our world was reduced to a uniform rectangle, a tidy system of nine planets, completely disregarding the existence of any others. I knew nothing of planets trillions of miles from the sun, of moons and galaxies in a far-off world. Finally, I learned. I chanced upon exoplanets in the news, and I read articles about them online. I read, I listened, and I watched. When I gazed up at the stars in the sky, they built upon each other, each getting fainter and fainter until I could imagine a whole field of them, extending on for eternity. In its pathline it encompassed even the furthest celestial bodies, formally known as exoplanets: havens of possibility and undiscovered magic. But what are exoplanets?

The word “exoplanet” is actually an abbreviation of extrasolar planet, or any planet that is outside of the Solar System. Their characteristics vary; their size, composition, and capacity to host life differ greatly. For a long time, we were unaware that exoplanets even existed. The idea, like many radical scientific hypotheses, seemed ludicrous at the time. However, in 1992, the extraordinary happened: evidence of exoplanets was discovered. Some neutron stars are called pulsars; they transmit pulses in radio frequencies at an extremely regular pace. Astronomers detected an abnormality in the intervals of the pulses of the pulsar PSR B1257+12, and discovered that two exoplanets were orbiting the star, disrupting its transmissions. The discovery was unexpected but beautiful, in the way scientific research often is — you can accidentally stumble across incredibly meaningful evidence. After that, the world of space exploration and exoplanet research was opened wide, and researchers began devoting their time to finding and characterizing new exoplanets.

Researchers detect exoplanets in five main ways. The first and one of the most commonly used is the transit method; it searches for the shadows produced whenever an exoplanet passes between a star and its observer, dimming the light cast by the star. Then, there is radial velocity; orbiting exoplanets can not only dim light but also cause stars to move in space, transforming the color of the light that astronomers observe. Direct imaging is straightforward as its name implies; astronomers dim the light from stars that exoplanets orbit in order to capture photos of the planets. With gravitational microlensing, light from a star is manipulated by gravity as an exoplanet passes between the star and the human astronomers on Earth. Finally, astrometry focuses directly on the motion that an orbiting exoplanet could cause in a star; the stars with orbiting exoplanets move more in comparison to other stars.

At this point, you may be wondering: why does this apply to us? Why is there such a hurry to find tiny, far-off exoplanets that seem so inconsequential? There are two main reasons. First, research allows the world to gain more information about the universe, as well as the composition and formation of Earth. Having more research about a subject is almost never a bad thing. By observing newborn exoplanet systems, we can learn about the formation of planetary systems. We can also compare more planets to Earth, specifically analyzing the intersection of its properties with those of Earth-sized exoplanets. We can discover more about our planet — which brings us to the next reason why exoplanet research is so imperative. Earth is special. It has an atmosphere, water, and clean food. Organisms are able to exist here. There is a very small chance that some Earth-sized planets will be Earth-like as well, but it’s a chance that we want to explore. It could very well be the solution to our struggles with climate change. In the future, there is a chance that our planet could become uninhabitable, disfigured by climate change and global warming. We are working on technology to try and prevent that from happening, but other alternatives are being explored, such as the possibility of space travel: it could be possible to live on another planet outside our Solar System, as long as the conditions are perfect for maintaining life.

The future holds many possibilities; there is still a lot of research to be completed in this field. The chances of finding a perfect exoplanet that can host life are extremely minimal. However, scientists are not giving up hope; in the future, they will continue to measure the conditions and composition of exoplanets in habitable zones, in the hopes of finding that one perfect needle in the haystack. We’ve made a lot of progress in detecting and characterizing exoplanets so far. Space telescopes such as Kepler and CoRoT have allowed us to identify and locate different types of planets. However, we are currently actually not able to gather much information about exoplanets. We may vaguely know their composition and approximate location, but we do not have incredibly precise data. Space agencies are looking forward to detailed, remote characterization about exoplanets to gain greater insight about our world. 

It’s clear that we’ve only scratched the surface of what’s possible, and we still have a long way to go in exoplanet research. Vast progress has been made since the discovery of exoplanets, but there is still a long road ahead of us. The future is bright. Sometimes it’s hard to appreciate how small we are in this huge galaxy, so next time you gaze up at the night sky, try to imagine beyond the painted swirls of indigo and gray you see, beyond the tiny white pinpricks. Travel further back, to other stars and centers of planetary systems. Imagine billions and trillions of little planets outside of our sphere, spilling over the blank page and extending it infinitely. Every little dot is ripe with possibility.

Bibliography

“Exoplanets | Center for Astrophysics.” Www.cfa.harvard.edu, www.cfa.harvard.edu/research/topic/exoplanets. Accessed 11 Mar. 2025.

Kubota, Taylor. “Physics Professor Explains Exoplanets.” News.stanford.edu, 25 Jan. 2021, news.stanford.edu/stories/2021/01/stanford-explainer-exoplanets-earths.

NASA. “5 Ways to Find a Planet | Explore.” Exoplanet Exploration: Planets beyond Our Solar System, 

exoplanets.nasa.gov/alien-worlds/ways-to-find-a-planet/?intent=021. Accessed 11 Mar. 2025.

---. “How Many Exoplanets Are There? - NASA Science.” Science.nasa.gov, 22 Apr. 2024, science.nasa.gov/exoplanets/how-many-exoplanets-are-there/. Accessed 11 Mar. 2025.

Oriol. “ICMAB - Ignasi Ribas: “Present and Future of Exoplanet Research.”” Icmab.es, 2025, icmab.es/ignasi-ribas-present-and-future-of-exoplanet-research. Accessed 11 Mar. 2025.

Wenz, John. “How the First Exoplanets Were Discovered.” Astronomy Magazine, 8 Oct. 2019, www.astronomy.com/science/how-the-first-exoplanets-were-discovered/. Accessed 11 Mar. 2025.

“Your Guide to Exoplanets.” The Planetary Society, The Planetary Society, www.planetary.org/worlds/exoplanets. Accessed 11 Mar. 2025.