Page 41 - Curriculum Visions Dynamic Book

Heliosphere
The heliosphere, also called the magnetosphere, is the region over which the Sun’s magnetic influence and solar wind spreads. It is immense and reaches out beyond Pluto. It is like a giant, invisible teardrop-shaped bubble in space.
Because the Sun is continually moving through space, the heliosphere interacts with the surrounding interstellar medium.
The edge of the heliosphere is called the heliopause. It is a teardrop-shaped boundary around the Sun that is filled with both a solar magnetic field and the solar wind, which is made of protons and electrons. Ahead of the heliopause there may be bow shock waves similar in pattern to those that form
in front of a fast-moving boat or airplane. The long tail of the heliopause may reach 100 astronomical units from the Sun.
How the Sun affects the Earth
When we look at the Sun, we might imagine that its main effect is to provide light and heat. However,
the Sun sends out radiation over a much greater range. It also sends out charged particles that form the solar wind.
UV and X-rays
The main forms of radiation in addition to light
and heat are ultraviolet (UV) rays and X-rays. Ultraviolet rays react with oxygen in the air to produce ozone. Ozone absorbs ultraviolet radiation, acting as a natural shield against these rays, which are harmful to living things exposed to them for a long time.
X-rays from the Sun’s corona interact with the Earth’s upper atmosphere to produce the layer we call the ionosphere. The ionosphere helps bounce radio waves and so makes possible long-distance radio.
astronomical unit (au) The average distance from the Earth to the Sun (149,597,870 km).
heliopause The edge of the heliosphere.
heliosphere The entire range of influence of the Sun. It extends to the edge of the Solar System.
interstellar Between the stars.
ionosphere A part of the Earth’s atmosphere in which the number of ions (electrically charged particles) is enough to affect how radio waves move.
ozone A form of oxygen (O3) with three atoms in each molecule instead of the more usual two (O2).
pluto The ninth planet from the Sun and six planets farther from the Sun than the Earth.
radiation The transfer of energy in the form of waves (such as light and heat) or particles (such as from radioactive decay of a material).
radio waves A form of electromagnetic radiation, like light and heat. Radio waves have a longer wavelength than light waves.
solar wind The flow of tiny charged particles (called plasma) outward from the Sun.
ultraviolet A form of radiation that
is just beyond the violet end of the visible spectrum and so is called “ultra” (more than) violet. At the other end of the visible spectrum is “infra” (less than) red.
x-ray An invisible form of radiation that has extremely short wavelengths just beyond the ultraviolet.
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