The largest planet in our solar system is Jupiter. Here's why:

Size Comparison
Jupiter is significantly larger than all other planets in our solar system. In fact, it is more than 11 times the diameter of Earth, making it the largest planet by far.

Jupiter's Mass
Jupiter also has the highest mass among all the planets. Its mass is approximately 2.5 times greater than the combined mass of all the other planets in our solar system.

Formation
Jupiter's large size is believed to have been influenced by its formation process. Scientists think that Jupiter formed early in the history of the solar system by accumulating a large amount of gas and dust in its vicinity. Its strong gravitational pull allowed it to gather more and more material, eventually becoming the giant planet we see today.

Gas Giant
Jupiter is classified as a gas giant, which means it is primarily composed of hydrogen and helium gases. It does not have a solid surface like rocky planets such as Earth or Mars. Instead, its composition resembles that of a star, but it lacks the necessary mass to undergo nuclear fusion and become a star.

Distinct Features
Jupiter is known for its distinct features, including its colorful bands and swirling storms. The most famous storm on Jupiter is the Great Red Spot, a massive storm system that has been observed for centuries. This storm is so large that it could fit several Earths inside it.

Moons
Jupiter also has the largest number of moons in our solar system. It has at least 79 known moons, with the four largest ones being called the Galilean moons: Io, Europa, Ganymede, and Callisto. Ganymede, the largest moon in the solar system, is even larger than the planet Mercury.

Conclusion
In summary, Jupiter is the largest planet in our solar system based on its size, mass, and composition. Its immense size and unique features make it a fascinating object of study for scientists.