They are different - because they are unique - made that way by a DESIGNER. (Planetary uniqueness undermines evolutionary cosmology in our solar system).
the smallest. They don’t have the brightest colors. But they do hold the greatest mysteries.
We have roved across Mars, we have orbited Jupiter, we have even landed on Venus. But our only close look at the ice giants Neptune and Uranus came more than 30 years ago when the Voyager 2 spacecraft hurtled past on its way out of the solar system. It snapped a few pictures, then the planets faded from view. “Everything we know up close about these planets and their moons is based on that single fly-by,” says NASA scientist Amy Simon.
Now impetus is building to go back. The little we do know about these frigid planets suggests they are extremely weird.
--They have crooked magnetic fields,
--they’re colder than they should be and
--we don’t know why they spin in odd ways.
Understanding all this is important, because in the past two decades our sky surveys have started spotting planets around other stars, and worlds about the size of Uranus and Neptune are the most common type. That tells us mid-sized gassy planets are a basic ingredient of the universe." NewScientest
Through faith we understand that the worlds were framed by the word of God,..
Hebrews 11:3
"Neptune and Uranus are not the most distant objects in the solar system. They aren’t the biggest or 
We have roved across Mars, we have orbited Jupiter, we have even landed on Venus. But our only close look at the ice giants Neptune and Uranus came more than 30 years ago when the Voyager 2 spacecraft hurtled past on its way out of the solar system. It snapped a few pictures, then the planets faded from view. “Everything we know up close about these planets and their moons is based on that single fly-by,” says NASA scientist Amy Simon.
Now impetus is building to go back. The little we do know about these frigid planets suggests they are extremely weird.
--They have crooked magnetic fields,
--they’re colder than they should be and
--we don’t know why they spin in odd ways.
Understanding all this is important, because in the past two decades our sky surveys have started spotting planets around other stars, and worlds about the size of Uranus and Neptune are the most common type. That tells us mid-sized gassy planets are a basic ingredient of the universe." NewScientest