Less expensive. The cost difference between building a roundabout and a traffic signal is comparable. Where long-term costs are considered, roundabouts eliminate hardware, maintenance and electrical costs associated with traffic signals, which can cost between $5,000 and $10,000 per year.Roundabouts are also more effective during power outages.here long-term costs are considered, roundabouts eliminate hardware, maintenance and electrical costs associated with traffic signals, which can cost between $5,000 and $10,000 per year. Roundabouts are also more effective during power outages.
THE EARTH'S MAGNETOSPHERE. The magnetosphere is the Earth's magnetic environment. The Earth is a huge dipole (2-pole) magnet. The Earth's magnetic field is probably cause by its molten iron-nickel core. This magnetic field is aligned with the north and south poles, and has reversed many times during geologic history.
The ionosphere and the exosphere together make up the upper atmosphere (or thermosphere). The magnetosphere is the region above the Earth's surface in which charged particles are affected by the Earth's magnetic field. Another well-known layer of the atmosphere is the ozone layer, occupying much of the stratosphere. This layer is defined by its chemical composition - where ozone is especially abundant. The lowest layer of the atmosphere is called the troposphere. It ranges in thickness from 8km at the poles to 16km over the equator.