Researchers believe the planet was subject to a colossal pounding by an object twice the size of Earth.

Uranus, the seventh planet from the Sun, has an unusual tilt compared to the rest of the Solar System’s planets. While most planets have relatively small tilts, Uranus is tilted on its side, with its axis of rotation nearly parallel to its orbital plane. 

This has long been an enigma for astronomers and scientists alike.

Recent studies suggest that the gas had suffered a colossal pounding from a planet-sized cosmic object, which might explain its unique features. A team of researchers has hypothesized in the Astrophysical Journal that young Uranus had experienced a massive impact, possibly with an object twice the size of Earth, which led to its extreme axial tilt of 98 degrees, with its major moons orbiting in the same tilted plane. 

The impact has significantly altered the planet’s rotation, causing it to spin on its side.

This extraordinary but violent event has also produced lasting effects on the planet’s atmosphere, internal structure, and even its magnetic field.

It takes Uranus 84 Earth years to complete a full circle around the Sun. Credit: Wikipedia

The tilt affects, for example, the weather patterns on Uranus, leading to extreme seasonal variations. The planet’s magnetic field is also unique, with the magnetic poles located far from the geographic poles.

Uranus’ 27 known moons provide additional evidence to the planet’s violent history, due to their orbits: many of these moons have irregular and highly inclined orbits, which means they were disturbed by the pounding event.

Uranus is a gaseous cyan ice giant. Most of it is made out of water, ammonia, and methane in a supercritical phase of matter.

Uranus remains one of the least explored planets in our Solar System, because of its extreme distance from the star and harsh conditions on its surface. It was visible with the naked eye for millennia but recognized as a planet seven decades after its careful observation by William Herschel in 1781. Uranus was visited and pictured from close range by NASA’s Voyager-2 probe in 1986.

Most astrophysicists agree that Earth too formed as a result of a violent impact with a Mars-sized object, pointing out to its Moon as a piece of evidence of that past.