That last sentence is most relevant. See how it says gravity-induced changes in an astronomical body's rotational axis. That means that if a massive object comes close to the earth exerting torque on the earth through gravitation, it changes the body's rotational axis or orbital path.
You may be familiar with how a spinning top wobbles when friction causes it to slow-down. As the spinning top gets slower, its wobble gets more violent and chaotic. This is because the force of gravitation has a stronger effect as the rotational inertia weakens. Imagine what would happen if the earth shook as violently as a top about to tumble over. It would cause massive tsunamis across the globe and I don't think any living creature would appreciate the sudden forces exerted upon the earth.
Orion's Belt is North from the equator. The 38-degree angle is the Angle of Elevation formed by the line from the outermost pyramids. This is the angle formed between the Horizon and the line between the outermost pyramids. Look at the illustration on Wikihow for how to find North without a compass, Method Four of Eight: Using the Stars: Equator. The 50-degree angle is what we measure nowadays when we go back to 10,500 BC in a planitarium. That is because the earth's axis has been changed 12-degrees. When the Core of the Great Pyramid was built, the angle was nearly 38-degrees (not 50-degrees). When you are looking North at Orion's Belt from Egypt (in Africa) and you rotate the earth until you reach 50-degrees, North America has been rotated to a higher Latitude, which changes the Average Annual Temperature Range. The North Pole is frozen. The higher you go in Latitude, the colder the temperature becomes due to the amount of sunlight that area receives. That is why North America experienced previously unexplained cooling during the Younger Dryas climactic event. Look at a data table for the Effect of Latitude on Average Annual Temperature Range. You will see that it matches the Younger Dryas (2-6 degrees Celsius) for approximately a 12-degree change in Lattitude. I think every degree in Latitude is about 1/2 a degree in Annual Temperature Range (for that approxumate Latitude).