Could life on earth survive a large pole shift caused by an asteroid collision?
I became aware that there are people who believe that the earth's pole suddenly shifts. That is, its rotational axis changes rather than its magnetic axis. This is listed in wikipedia as follows:
Cataclysmic pole shift hypothesis
The cataclysmic pole shift hypothesis is the conjecture that there have been rapid shifts in the relative positions of the modern-day geographic locations of the poles and the axis of rotation of a planet. For the Earth, such a dynamic change could create calamities such as floods and tectonic events.
…
The field has attracted pseudoscientific authors offering a variety of evidence, including psychic readings.
…
http://en.wikipedia.org/wiki/Cataclysmic_pole_shift_hypothesis
While watching a chess game at the local club a fellow member told me that he'd found the solution for where oil came from. It was long and involved. One of its features required that the earth's axis be changed by 90 degrees due to the collision of an asteroid a few million years ago. The idea was that the earth's axis used to be in the plane of the earth's orbit, but then it was knocked into its current rotation axis tilt of around 23 degrees. This changed the climate and buried a lot of stuff.
The axis shift seemed to be an obvious weak link with the theory in that it involves the simplest physics. I told him that any asteroid large enough to change the earth's axis an appreciable amount (i.e. 70 degrees!) would cause so much damage as to destroy all life on the surface of the planet including its oceans. I'd have forgotten about it, but the other night, while listening to the radio, a guest appeared who had an idea that was similar. So this seems like a common target for pseudoscience.
And so my question is this: Would an asteroid collision sufficient to immediately change the earth's rotation axis wipe out all life on the planet?
Best Answer
Quite clearly this man’s theory is balderdash. A massive collision could change the tilt of the Earth’s axis, but that would be one hell of a torque. The collision would not be with an asteroid either, but with another planet that might be as big as Mars. Clearly nothing like this happened in recent geological history, though the Earth did suffer a collision of this magnitude a few 100 million years after gravitational accretion. A chunk from the collision spalled off to form the moon. This other planet probably was in some resonance condition around a Lagrange point.
This would be a devastating collision, which would doubtless change this planet into something else. The solar system has not experienced such collsions since its early evolution. The solar system is now staid and respectable. Velikovskian things just do not happen.