Did Early Earth Spin On Its Side? | SETI Institute
http://www.seti.org/seti-institute/press-release/did-early-earth-spin-its-side
New theoretical modeling of the ancient history of the Earth and the Moon suggests that the giant collision
that spawned our natural satellite may have left Earth spinning very fast, and with its spin axis highly tilted.
Computer simulations of what followed the collision, sometimes referred to as the “big whack,” show that, following this event,
and as the young Moon’s orbit was getting bigger, the Earth lost much of its spin as well gained a nearly upright orientation with
respect to the ecliptic. The simulations give new insight into the question of whether planets with big moons are more likely to
have moderate climates and life.
“Despite smart people working on this problem for fifty years, we’re still discovering surprisingly basic things about the earliest
history of our world,” says Matija Cuk a scientist at the SETI Institute and lead researcher for the simulations. “It’s quite humbling.”
Since the nineteenth century, scientists have known that the Moon is gradually moving away from Earth and that or planet’s spin is
simultaneously slowing down. The cause is the ocean tides raised by the Moon which slowly dissipate energy as they move across the ocean
basins. This energy has to come from somewhere, resulting in a slowing down of Earth’s rotation, with our days very slowly getting longer.