Not that long ago,, astronomers weren’t sure that exoplanets even existed. Now we know that there are thousands of them and that most stars probably harbour exoplanets. There could be hundreds of billions of exoplanets in the Milky Way, by some estimates. So there’s no reason to think that stars in other galaxies don’t host planets.
But to find one of those planets in another galaxy? That is a significant scientific achievement.
Astronomers find most exoplanets in our galaxy with the
transit method. When a planet passes between us and its star, the star’s light dips a tiny amount as the planet blocks out some of the light. Measuring that slight dip is very difficult, but that’s what planet-hunters like NASA’s
Transiting Exoplanet Survey Satellite (TESS) do. That method won’t work in another galaxy. It’s difficult to even discern individual stars in other galaxies, let alone detect the minuscule light blockage when a potential exoplanet transits in front of its star.
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