Is Jupiter the biggest planet in the solar system now?

Answer 1

Jupiter is the largest planet in the Solar System. There are many larger planets outside of the Solar System but it's the largest in THIS solar system.

Recently discovered "exoplanets", planets orbiting other stars, range in size from fairly large to positively enormous. (Our sensors are not yet good enough to detect Earth-sized planets around other stars, but soon, soon..... ) The biggest are up to 50 times more massive than Jupiter, the point at which a massive body becomes massive enough to cause nuclear fusion - and becomes a tiny star.
Yes it's the biggest. Even if it is a gas planet.
Yes. Jupiter is a medium-sized gas giant, the largest planet in our solar system. It is more than twice as massive as the next-largest planet, Saturn, and is more than 3000 times Earth's mass. However, it is still about 1/1000 the mass of the sun.