If we wait enough time, we might not have size envy against the largest planet of our solar system. Jupiter is about 2 and a half times larger than all other planets in the solar system. However, the gas giant is losing volume at a steady rate.
Jupiter is the closest planet in our solar system to a star. If it were 75 times as massive, it would be able to fuse hydrogen and become a star. As it stands, however, Jupiter still radiates a large amount of heat. That is actually the reason it's shrinking. It is radiating out more heat than it gets from the Sun. This imbalance results in the planet shrinking about 2cm each year. Scientists estimate that the planet was originally much hotter and bout twice its size right now.