* Planets are common: We know planets are incredibly common in our own Milky Way galaxy. Since 2009, we've discovered thousands of exoplanets, and there are likely billions more waiting to be found.
* Galaxies are similar: While galaxies come in different sizes and shapes, they share fundamental similarities. All galaxies contain stars, and stars form planets.
* Other galaxies are not that different: Observations suggest that star formation processes are very similar across different galaxies.
* Direct detection: We've even started detecting exoplanets in other galaxies, albeit indirectly. Astronomers have observed the gravitational "wobble" of stars in a galaxy called Andromeda, indicating the presence of planets around them.
So, while we haven't directly observed a planet in another galaxy, the overwhelming evidence suggests they are incredibly common, and we are just starting to explore their vast numbers!
