Jim Stehr and I had a five-minute conversation yesterday pertaining to Rogues, rogue asteroids, planets, and stars potentially passing near enough to Earth to have an effect. We were waiting in line to be admitted to a presentation ostensibly meant to give us insight into character creation in fiction writing.
I had googled Earth’s Tilt the day before, and Jim and I talked about two articles I had read. According to Wikipedia, Earth currently has an axial tilt of about 23.44°. This value remains about the same relative to a stationary orbital plane. But the ecliptic (Earth’s orbit) moves due to planetary perturbations, and the ecliptic is not a fixed quantity. At present, Earth’s tilt is decreasing at a rate of about 46.8 minutes, one sixtieth of a degree, per century.
An article from Astrology informed us that the original tilt was almost certainly determined by a collision with a large proto-planet some 4.4 billion years ago as the Earth was forming.
Jim and I started our conversation by mutually agreeing that a near miss of a planetary sized Rogue would certainly disrupt Earth’s current tilt causing immediate changes to our four seasons and to Earth’s climatology.
Then Jim gave a rapid-fire assessment of how lucky we are as a planet. The presentation by William Hatfield was engaging, but I found my mind wandering back to my conversation with Jim, so here are the notes I wrote while waiting for the presentation to be over.
- We are in a relatively quiet corner of the galaxy.
- The larger systems near-by absorb the impacts of Rogue collisions.
- Early in Earth’s creation the moon was knocked off and went into our orbit, but a second moon was absorbed and resides in Earth’s core providing us with extremely valuable protection in the form of its magnetic field.
After the meeting, Jim agreed with Neil deGrasse Tyson’s speculation that the cosmos may be teeming with life, but Jim added that the kind of cognitive existence we enjoy is probably very rare.