Referencing Interstate 10
Observing the flatness of Interstate 10 in the Sonoran Desert.
What Is It?
Interstate 10 is a highway that stretches across the southern United States, from Santa Monica, California, to Jacksonville, Florida, covering approximately 2,460 miles (3,960 kilometers). Among the segments of Interstate 10, the stretch through the Sonoran Desert in southern California, is known to be relatively level elevation over a significant distance. I’m interested to see how these distances and elevations correspond to curvature of Earth’s surface.
Through the Sonoran Desert
The part of I-10 I’m analyzing here is the segment between Palm Springs and Indio.
Location: This segment is in southeastern California, running through the Coachella Valley.
Distance: Approximately 50 to 60 miles (80 to 97 kilometers).
Elevation: The elevation in this stretch generally ranges from about 200 to 500 feet (60 to 150 meters) above sea level.
The important thing to note here is the 300-foot difference from the lowest to highest elevations. This takes place over a span of 60 miles.
Reasons For Relatively Level Elevation
As it turns out, this particular site happens to be an excellent choice for the observation of flatness due to the following.
Desert Terrain: The Sonoran Desert features a relatively flat, gently rolling terrain, which allows for a consistent elevation profile.
Engineering: The highway was designed with the goal of minimizing elevation changes to enhance travel efficiency across the desert.
Curve Estimate
As outlined, we know the distance is 60 miles and the documented difference of elevations along this segment of I-10 is 300 feet. Now, let’s compare that with what the purported curvature rate of Earth suggests should be observable.
Over a 60-mile distance on Earth's surface, the curvature would cause a drop of about 2,404 feet (approximately 733 meters). This means that, due to Earth's curvature, the center of a 60-mile stretch would be roughly 2,404 feet higher than the ends. However, as demonstrated using publicly available data concerning the difference of elevations along the segment, we only measure 300 feet.
Conclusion
The Sonoran Desert segment of I-10 between Palm Springs and Indio is one of the most level stretches of the highway in the US, with relatively minor elevation changes compared to the more varied elevations encountered elsewhere along its route. This stretch stands out due to the flat nature of the desert terrain, and the engineering involved, which minimizes its elevation variation. The measured difference of 300 feet in elevation along this highway doesn’t align with the 2,404 feet suggested by curvature of the Earth.