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Among extrasolar planets, axial tilts are not known for certain, though most hot Jupiters are believed to possess negligible to no axial tilt as a result of their proximity to their stars.
The initial axial tilt of a planet determined by giant impacts can be substantially changed by stellar tides if the planet is close to its star and by satellite tides if the planet has a large satellite.
The Earth's orbit grows slowly more and less elliptical, even as the angle of the planet's axial tilt, and the wobble of the poles as the planet spins (much like what you see with a spinning top), also change slightly over thousands of years.
"I don't think [changes in a planet's axial tilt] would be a problem for the development of advanced life," as any type of life would adapt to changing circumstances anyway, says planetary scientist Sara Seager of the Massachusetts Institute of Technology in Cambridge.
In 1781, he estimated the rotation period of Mars as 24h 39m 21.67s and measured the axial tilt of the planet's poles to the orbital plane as 28.5°.
This is significantly smaller than that of Jupiter, which has the second smallest axial tilt of all planets at 3.1 degrees.
This results in the axial tilt of accreted planets ranging from 0 to 180 degrees with any direction as likely as any other with both prograde and retrograde spins equally probable.
The Moon's gravitational interaction with Earth stimulates ocean tides, stabilizes the axial tilt and gradually slows the planet's rotation.
Without the moon, gravitational perturbations from other planets, notably nearby Venus and massive Jupiter, would greatly disturb Earth's axial tilt, with vast consequences for the planet's climate.
Planets with a large axial tilt are less likely to enter snowball states and can retain liquid water further from their star.
