Here are the planets in our solar system ordered from longest year (longest orbital period) to shortest year (shortest orbital period):

1. Neptune: 165 Earth years

2. Uranus: 84 Earth years

3. Saturn: 29.5 Earth years

4. Jupiter: 11.9 Earth years

5. Mars: 687 Earth days (almost 2 Earth years)

6. Earth: 365.25 Earth days

7. Venus: 225 Earth days

8. Mercury: 88 Earth days

Important Note: A year is defined as the time it takes a planet to complete one full orbit around the Sun.