Uranus on its side
Claim in the list: Uranus rotates “on its side” because its axis is tilted almost 90°, caused by an ancient collision with an object twice as large as Earth.
Verification: Its axial tilt is about 98° relative to the perpendicular to its orbital plane. A giant impact is a leading explanation, but the details are not settled. NASA cautiously says the tilt may have resulted from a collision with an Earth-sized body. Scientific models examine a range of impactor masses, including roughly two to three Earth masses; some studies consider alternatives or multiple impacts. Thus, “twice as large” is not an observed fact or the only model.
Conclusion: Uranus does have an extreme tilt of about 98°. An ancient giant impact is an important hypothesis, but the impactor’s exact mass and event history remain under study.