Free Astronomy Magazine November-December 2025

6 NOVEMBER-DECEMBER 2025 ASTRO PUBLISHING M ichel Mayor (left) and Didier Queloz worked together to dis- cover the planet 51 Pegasi b in 1995, the first one to be discovered orbiting a Sun-like star. Thanks to that discov- ery, the two researchers won the Nobel Prize in Physics 2019. confirmed by follow-up observa- tions, often using an additional tel- escope, and that takes time. That’s why there is a long list of candidates in the NASA Exoplanet Archive (hosted by NExScI) waiting to be confirmed. “We really need the whole community working together if we want to maximize our invest- ments in these missions that are churning out exoplanets candi- dates,” said Aurora Kesseli, the deputy science lead for the NASA Exoplanet Archive at IPAC. “A big part of what we do at NExScI is build tools that help the community go out and turn candidate planets into confirmed planets.” The rate of exoplanet discoveries has acceler- ated in recent years (the database reached 5,000 confirmed exoplanets just three years ago), and this trend seems likely to continue. Kesseli and her colleagues anticipate receiving thousands of additional exoplanet candidates from the ESA (European Space Agency) Gaia mission, which finds planets through a technique called astrometry, and NASA’s Nancy Grace Roman Space Telescope, which will discover thousands of new exoplanets primarily through a technique called gravitational mi- crolensing. At NASA, the future of exoplanet science will emphasize finding rocky planets similar to Earth and studying their atmos- pheres for biosignatures — any characteristic, element, molecule, substance, or feature that can be used as evidence of past or present life. NASA’s James Webb Space Tele- scope has already analyzed the chemistry of over 100 exoplanet at- mospheres. But studying the atmos- pheres of planets the size and temperature of Earth will require new technology. Specifically, scien- tists need better tools to block the glare of the star a planet orbits. And in the case of an Earth-like planet, the glare would be significant: The Sun is about 10 billion times brighter than Earth — which would be more than enough to drown out our home planet’s light if viewed by a distant observer. NASA has two main initiatives to try overcoming this hurdle. The Roman telescope will carry a technology demonstra- tion instrument called the Roman Coronagraph that will test new technologies for blocking starlight and making faint planets visible. At its peak performance, the corona- graph should be able to directly image a planet the size and temper- ature of Jupiter orbiting a star like our Sun, and at a similar distance from that star. With its microlensing survey and coronagraphic observa- tions, Roman will reveal new details about the diversity of planetary sys- tems, showing how common solar systems like our own may be across the galaxy. Additional advances in coronagraph technology will be needed to build a coronagraph that can detect a planet like Earth. NASA is working on a concept for such a mission, currently named the Habit- able Worlds Observatory. !