1 For an observer on the ground with eye level at h = 5 ft 7 in (1.70 m), the horizon is at a distance of 2.9 miles (4.7 km). 2  For an observer standing on a hill or tower 100 feet (30 m) in height, the horizon is at a distance of 12.2 miles (19.6 km).
The mantle is a layer of the Earth between the crust and the core. The upper mantle starts below the crust and goes down to a depth of around 200 miles to the boundary with the lower mantle. The temperature of the mantle ranges from 900 degrees Fahrenheit near the crust to as high as 7000 degrees near the core.he Upper Mantle: Temperature and Depth. The upper mantle begins just beneath the crust and ends at the lower mantle. The thickness of the upper mantle is between 200 and 250 miles.
The Lithospheres temperature is about 400 degrees celsius. The lithosphere (lower mantle) is rigid part of the mantle. The lithosphere is not only part of the mantle it is the crust and the upper part of the mantle together. The depth of the lithosphere is 50-100 km thick.he entire earth's crust occupies just 1% of the earth's volume. The Earth's crust thickness is 30 km thick. The temperature of the crust is 2oo degrees Celsius (392 Fahrenheit) to 400 degrees Celsius (752 Fahrenheit).