Carlos Solis
The National Aeronautics and Space Administration (NASA) has confirmed the discovery of 6,000 exoplanets, planets that exist outside our Solar System.
Researchers say the search for these distant worlds will accelerate as a new generation of telescopes is launched.
What do you need to know?
So, the science of exoplanets has reached a new milestone. NASA has announced that there are now 6,000 confirmed exoplanets. They vary widely in type and size, and in the kinds of stars they orbit.
The era of exoplanet discovery began relatively recently—in 1992. At that time, astronomers found a pair of such objects orbiting a pulsar. Then, in 1995, scientists discovered the first exoplanet orbiting a main-sequence star (a star fusing hydrogen in its core, like the Sun). With the launch of NASA’s Kepler and TESS missions, the number of confirmed exoplanets continued to grow.
By 2015, the agency announced that the Kepler telescope had discovered its thousandth exoplanet. The year 2016 was significant for discoveries, as scientists identified nearly 1,500 such objects that year alone. By March 2022, the total number of discovered exoplanets had reached 5,000.
And now NASA has confirmed another thousand. Is that a lot? Compared to the hundreds of billions of exoplanets that may exist in the Milky Way, it’s small. But for a young spacefaring civilization like ours, it’s a milestone worth celebrating.
That’s impressive when you consider how difficult these detections are. Many exoplanets are hidden in the glare of their stars or sit incredibly far away.
The science of exoplanets is not just about counting worlds. These discovered planets help us understand the history of our Solar System and the conditions on Earth.
Many of the discovered exoplanets are unlike anything in our system. Among them are hot Jupiters—massive gas giants that complete an orbit in just a few days. Some planets have ultra-short orbital periods measured in hours. Others are so close to their stars that they are tidally locked, like the Moon is to Earth.
Some have extreme temperatures, pressures, and chemical makeups. It can rain iron on some of them. Some are covered by global oceans, while others are shrouded in toxic atmospheres.
Why search for them?
All these searches boil down to one big question: Are we alone in the universe?
“Each type of planet we discover gives us information about the conditions of their formation and, ultimately, about how common Earth-like planets are and where we should look for them,” said Don Helin, head of NASA’s Exoplanet Exploration Program at the Jet Propulsion Laboratory. Helin added that this knowledge is essential if humanity wants to find out whether we are alone in the universe.
Most exoplanet discoveries are indirect. The transit method finds a planet by measuring how much light the planet blocks as it passes in front of its star. The radial velocity method detects tiny wobbles in a star’s motion caused by orbiting planets by measuring shifts in the star’s spectral lines.
Kepler and TESS mainly used the transit method, which accounts for the largest share of discoveries—about 4,500. The radial velocity method is the next most productive, responsible for roughly 1,140 discoveries.
Only direct imaging combined with spectroscopy currently lets scientists determine the chemical composition of an exoplanet’s atmosphere. That technique is technically challenging, so there are only around 100 direct images of exoplanets.
Six thousand confirmed planets beyond our Solar System is a major milestone. But many candidate exoplanets still await confirmation. As of July 2025, the TESS list contained 7,655 exoplanet candidates, of which just over 600 had been confirmed.
The era of exoplanet discovery is shifting. Researchers are getting more targeted in their searches and focusing on specific kinds of planets. After the launch of the European Space Agency’s (ESA) PLATO spacecraft in 2026, it will hunt for rocky exoplanets around Sun-like stars. NASA’s Habitable Worlds Observatory, now in development, will focus on finding planets that could support life. Meanwhile, missions like ESA’s CHEOPS and ARIEL will carry out in-depth studies of already known exoplanets.
Photo: NASA
