NASA reached 6,000 confirmed exoplanets: what the count reveals

On September 17, 2025, NASA announced that the number of confirmed exoplanets in its count had reached 6,000. An exoplanet is a planet located outside the solar system. Most orbit other stars, although there are also wandering worlds that are not bound to any star. NASA explained that scientists around the world add planets to the count as they are confirmed; for that reason, no planet is permanently designated “the 6,000th exoplanet.” The announcement described a milestone in a dynamic catalog, not a fixed position.

The NASA Science page on exoplanets reports more than 6,300 confirmed worlds. The agency’s exoplanet catalog brings together confirmed objects and is updated continuously. The two figures therefore correspond to different points in the count: the 6,000 figure was announced in September 2025, while the NASA Science page gives the later total.

Three decades of searching for other worlds

The 2025 announcement came thirty years after the first planet discovered around a Sun-like star was identified in 1995. A few planets around stars that had exhausted their fuel and collapsed had been identified earlier. Since then, new detection techniques and observations from space- and ground-based telescopes have expanded the known inventory.

The 6,000 were confirmed planets. In the same article, NASA said that more than 8,000 additional candidates were awaiting confirmation. A candidate is a signal that may be caused by a planet. To check it, teams make follow-up observations that help assess other possible explanations. NASA says this process usually requires follow-up, often with another telescope, and takes time.

The count is overseen by NASA’s Exoplanet Science Institute (NExScI), based at IPAC, a center for astrophysics and planetary science data and research at the California Institute of Technology (Caltech) in Pasadena. NASA published the announcement on September 17, 2025, and said the article was updated on September 22 of that year.

How distant planets are detected

Most exoplanets are difficult to photograph directly: their faint light is lost in the glare of the star they orbit. In its 2025 article, NASA said that direct images had been obtained of fewer than 100 exoplanets. For many others, the planet’s presence is inferred from the effects it has on its star or on the light reaching us.

One indirect technique is the transit method. When a planet passes in front of its star from our perspective, the star’s apparent brightness decreases for a short time. Astronomers can detect a signal consistent with a planet this way; follow-up observations help determine whether it corresponds to a confirmed object.

Detection techniques have revealed highly diverse worlds. NASA describes rocky planets and gas giants, planets orbiting close to their stars, systems with two stars, and planets around dead stars. It also mentions wandering worlds, lava-covered planets, and others with very low densities. Comparing their properties provides information about the conditions under which planets can form and the variety of planetary systems.

What comparing planets can tell us

The catalog makes it possible to examine how known planets are distributed and compare that population with the solar system. NASA notes that our system has the same number of rocky planets as giants, while rocky planets appear to be more common in the universe. This comparison helps shape questions about the formation and diversity of planetary systems.

The habitable zone is the region around a star where, under certain conditions, liquid water could exist on a planet’s surface. NASA also describes the search for rocky planets similar to Earth and the study of their atmospheres for biosignatures: features, elements, molecules, or substances that could be used as evidence of past or present life.

According to NASA’s 2025 article, the James Webb Space Telescope had already analyzed the chemistry of more than 100 exoplanet atmospheres. The agency explains that studying the atmospheres of planets similar to Earth in size and temperature requires technologies capable of better blocking the glare of the host star. The Sun, for example, is about 10 billion times brighter than Earth, according to that article.

Roman and upcoming observations

In its 2025 announcement, NASA presented the Nancy Grace Roman Space Telescope as a future mission. The agency expects it to discover thousands of exoplanets, mainly through gravitational microlensing, which uses the effect of gravity on light. Roman will also carry an experimental coronagraph to test technologies that block some starlight and make faint planets visible.

NASA Science reports that Roman launched on August 30 and will begin its science work in early 2027. The mission will contribute to the study of exoplanets. The coronagraph is a technology demonstration: according to NASA’s projection, at its maximum performance it could directly image a planet the size and temperature of Jupiter at a distance comparable to that of a star like the Sun.

NASA is also working on the Habitable Worlds Observatory concept, a mission intended to develop technologies for detecting Earth-like planets. The agency says further advances in coronagraphs will be needed to observe a planet like ours. Thus, the count of confirmed exoplanets provides an inventory that continues to grow, while current and future missions expand observations of these worlds and their systems.