“There was almost certainly a high-energy collision with a foreign, out-of-orbit object that struck our young Earth in the early stages of the Solar System, and that collision was required to give rise to our Moon. But it was very likely much smaller than Mars-sized, and it was almost certainly a sturdy strike, rather than a glancing collision. Instead of a cloud of rock fragments, the structure that formed was a new type of extended, vaporized disk known as a synestia. And over time, it settled down to form our Earth and Moon as we know them today.
At the end of the early stages of our Solar System, it was as promising as it could be for life. With a central star, three atmosphere-rich rocky worlds, the raw ingredients for life, and with gas giants only existing much further beyond, all the pieces were in place. We know we got lucky for humans to arise. But with this new understanding, we also think the possibility for life like us has happened millions of times before all throughout the Milky Way.”
One of the deepest existential questions we can ask about the Universe is how, after more than 9 billion years, all the phenomena in our cosmic history led to the creation of planet Earth. Going from an environment where stars were actively forming to one where the Sun, Earth, and all the other planets were in place is a daunting task for people who create scientific simulations of our early environment, and involves gravitational interactions, planetary migrations and ejections, and even enormously energetic collisions between planets and proto-planets.
Earth precesses around its axis every ~26000 years.
But in addition to this precession, there is an extra wobble that was observed by Kustner and later followed up by Seth Carlo Chandler, Jr called the Chandler Wobble that occurs at a much smaller time scale.
In 1888, Kustner found that the latitude of Berlin had changed slightly
during his observations of the night sky.
Therefore in 1891,Chandler. decided to conduct a 14 month study examining this change. The following is a plot of the spiral path taken by the earth’s axis over that 14 month period.
The following plot shows the motion from 1909 – 2001.
Although many theories indicate that this is due to the fact that earth is not a perfect spherical rigid body, it is still not entirely clear on the mechanism that drives earth into this small wobbly motion.
If you took a closer look at the plots you would find that this wobble is of the order of a couple of meters which most certainly does not seem like a lot.
But if you are an astronomer if you do not account for this correction, you might just end up pointing your telescope at the wrong object