It is challenging to determine the exact sizes of planetary systems around other stars with complete certainty due to the limitations of current observational techniques. However, astronomers have discovered numerous exoplanetary systems, some of which are believed to be comparable in scale to our own solar system.
One notable example is the TRAPPIST-1 system, which was discovered in 2016. TRAPPIST-1 is a small, ultra-cool dwarf star located about 39 light-years away from Earth. It has at least seven confirmed planets, with sizes similar to Earth and orbiting relatively close to the star. This compact system sparked great interest in the scientific community due to the potential for these planets to harbor liquid water, raising the possibility of habitable conditions.
Another fascinating system is Kepler-90, located approximately 2,545 light-years away. In 2017, astronomers using NASA's Kepler space telescope announced the discovery of an eighth planet orbiting Kepler-90, making it the first known star beyond our solar system to host as many planets as our own.
These examples illustrate that planetary systems with multiple planets exist in our galaxy, and while not all of them have been detected or characterized yet, it is reasonable to assume that there are other systems of comparable scale to our own. As observational techniques improve and new missions, such as the upcoming James Webb Space Telescope, are launched, we can expect to uncover more details about the diversity of exoplanetary systems.