Slide 29 of 49

The collision of the Mars-sized object with the Earth established the Earth's axial tilt at 23.5°, which is ideal for maintaining optimal temperatures on the Earth. In addition, the presence of the moon has kept the Earth's tilt consistent. In contrast, the axial tilt of the other planets has varied widely through the history of the Solar System. Why is axial tilt important? A planet with a large axial tilt will experience extremes of temperature as the star shines predominantly on one portion of the globe. The axial tilt is also designed to optimize the ability of the continents to support life. The majority of the Earth's land mass is located north of the equator. It just so happens that during the summer in the northern continents, the Earth is at its farthest distance from the Sun, which keeps the northern hemisphere cooler in the summer and warmer in the winter.