Why is Uranus Lying on its Side? The Ice Giant Mystery Explained

[00:00:00]Scientists think Uranus ended up lying [music] flat for one of two reasons. The first, during its formation, Uranus collided with a massive body. That impact knocked its rotational axis severely off course.

[00:00:10]To tip something [music] 90 plus degrees, the impactor had to be enormous because Uranus is no lightweight. It's the third largest planet in the solar system by volume, fourth by mass, [music] 65 times bigger than Earth.

[00:00:21]Knocking Uranus over was no small feat.

[00:00:23]The second theory, Uranus' orbit was destined to dictate its posture. The combined gravitational pull of Saturn, Neptune, and Jupiter caused Uranus' axis to slowly shift until it was fully lying [music] flat. Either way, Uranus didn't choose this. External forces pushed it there.

[00:00:38]But despite its undignified posture, Uranus is still breathtakingly beautiful to look at. It's a stunning deep blue, like a giant sapphire floating in space.

[00:00:46]Because Uranus and Neptune differ from the gas giants in composition, astronomers created a separate category for them, ice giants. [music] As an ice giant, Uranus has 13 rings, dim but still enough to add to its beauty.

[00:00:58]Uranus' atmosphere is mainly hydrogen, helium, methane, and argon. Beneath that blue-green haze lies an endless ocean of ice.

[00:01:05]The interior likely contains abundant heavy elements with a mantle made of methane and ammonia ice, possibly with water mixed in, and a core of ice and rock.