Ionizing radiation surrounds us.
Where does most of the ionizing radiation that bombards our Earth come from? Very little of the ionizing radiation that we are exposed to comes from radio towers or power lines (zero) or nuclear power plants (almost zero). In fact, nearly all (~ 4/5 or 80%) of the ionizing radiation that bombards us is due to natural residual radioactive decay products, part of the stuff our Earth is made from. These radioactive elements are the remnants of the evolution of the universe. Nearly all the rest of the ionizing radiation we are exposed to (~1/5 or 20%) comes from our Sun.
The center of our Earth is kept molten from the heat produced by residual, long lived radioactive decay, while our Sun produces heat through nuclear fusion (converting hydrogen, the lightest element, to helium, the next lightest element, and releasing a tremendous amount of energy in the process). While most of the energy from the Sun comes to the Earth in form of electromagnetic waves (heat and light), complex magneto-hydronamic processes (basically hot gases and strong magnetic fields) can accelerate particles (mostly protons) to high energies. Most of the particles that hit our Earth comes from our Sun (a few arrive from other stellar objects). When these particles collide with the Earth's atmosphere, we are showered with a number of complex, energetic particles (ionizing radiation).
All of our energy that we use on a daily basis (wood, coal, geothermal, wind, solar, nuclear) is ultimately derived from either fission (spontaneous radioactive decay) or fusion. Fusion (from the Sun) provides most of the energy we currently use (wood, coal, natural gas, wind, solar) while fission keeps the center of the Earth molten (sometimes this energy is extracted as geothermal energy and at other times we can see this energy released in the form of lava flows or geyers such as "Old Faithful" at Yellowstone National park.) We mine these radioactive minerals from the Earth, a small fraction of which can be used in nuclear reactors. However, more spontaneous nuclear fission events occur every second in our Earth than from all the nuclear power plants built on the Earth.
(Technically a little bit of energy is derived from ocean waves. This form of energy is essentially gravitational energy stolen from the gravitational interaction of the Earth, moon, and sun. But this would destroy the alliteration of "all energy comes from either fission or fusion".)
The Movie (requires Quicktime w H.264 Codec)
For the most part, we (humans) can not directly observe ionizing radiation. However, we make instruments that can allow these particles to be visualized. The movie above shows an instrument called a "cloud chamber" (located in a wonderful place called the Exploratorium in San Francisco). The cloud chamber is capable of giving a visual representation of many of these energetic particles.
The mist that you see is a mist of alcohol (usually methyl alcohol as opposed to the consumable kind, ethyl alcohol). When an ionizing particle (a proton, an electron, a muon, a helium nucleus, etc. mostly derived from our Sun) passes through this alcohol mist it causes the alcohol to condense, forming a little track. The track shows us where the particle passed, as it slowly falls to the bottom of the tank.
A quarter is roughly one square inch in area, and gives an idea of how many particles pass through every square inch every second. If you look at the video, you will see that approximately 2 tracks are formed every second through every quarter sized area (2 ionizing particles per square inch per second).
High energy particles are everywhere. For the most part you just can not see them. On every square inch of your body you are are exposed to about 2 of these particles every second (some particles are stopped by the skin, some deposit all their energy in the body, and some are so energetic they simply pass through the body completely). Plants and animals (and humans) have been exposed and have evolved in this natural background radiation since life first began to form on the earth (3.8 billion years ago for bacteria, 3 billion years ago for photosynthesis, 300 million years ago for dragonflies, 200 million years ago for mammals, 2.5 million years ago for humanoids).
Where does most of the ionizing radiation that bombards our Earth come from? Very little of the ionizing radiation that we are exposed to comes from radio towers or power lines (zero) or nuclear power plants (almost zero). In fact, nearly all (~ 4/5 or 80%) of the ionizing radiation that bombards us is due to natural residual radioactive decay products, part of the stuff our Earth is made from. These radioactive elements are the remnants of the evolution of the universe. Nearly all the rest of the ionizing radiation we are exposed to (~1/5 or 20%) comes from our Sun.
The center of our Earth is kept molten from the heat produced by residual, long lived radioactive decay, while our Sun produces heat through nuclear fusion (converting hydrogen, the lightest element, to helium, the next lightest element, and releasing a tremendous amount of energy in the process). While most of the energy from the Sun comes to the Earth in form of electromagnetic waves (heat and light), complex magneto-hydronamic processes (basically hot gases and strong magnetic fields) can accelerate particles (mostly protons) to high energies. Most of the particles that hit our Earth comes from our Sun (a few arrive from other stellar objects). When these particles collide with the Earth's atmosphere, we are showered with a number of complex, energetic particles (ionizing radiation).
All of our energy that we use on a daily basis (wood, coal, geothermal, wind, solar, nuclear) is ultimately derived from either fission (spontaneous radioactive decay) or fusion. Fusion (from the Sun) provides most of the energy we currently use (wood, coal, natural gas, wind, solar) while fission keeps the center of the Earth molten (sometimes this energy is extracted as geothermal energy and at other times we can see this energy released in the form of lava flows or geyers such as "Old Faithful" at Yellowstone National park.) We mine these radioactive minerals from the Earth, a small fraction of which can be used in nuclear reactors. However, more spontaneous nuclear fission events occur every second in our Earth than from all the nuclear power plants built on the Earth.
(Technically a little bit of energy is derived from ocean waves. This form of energy is essentially gravitational energy stolen from the gravitational interaction of the Earth, moon, and sun. But this would destroy the alliteration of "all energy comes from either fission or fusion".)
The Movie (requires Quicktime w H.264 Codec)
For the most part, we (humans) can not directly observe ionizing radiation. However, we make instruments that can allow these particles to be visualized. The movie above shows an instrument called a "cloud chamber" (located in a wonderful place called the Exploratorium in San Francisco). The cloud chamber is capable of giving a visual representation of many of these energetic particles.
The mist that you see is a mist of alcohol (usually methyl alcohol as opposed to the consumable kind, ethyl alcohol). When an ionizing particle (a proton, an electron, a muon, a helium nucleus, etc. mostly derived from our Sun) passes through this alcohol mist it causes the alcohol to condense, forming a little track. The track shows us where the particle passed, as it slowly falls to the bottom of the tank.
A quarter is roughly one square inch in area, and gives an idea of how many particles pass through every square inch every second. If you look at the video, you will see that approximately 2 tracks are formed every second through every quarter sized area (2 ionizing particles per square inch per second).
High energy particles are everywhere. For the most part you just can not see them. On every square inch of your body you are are exposed to about 2 of these particles every second (some particles are stopped by the skin, some deposit all their energy in the body, and some are so energetic they simply pass through the body completely). Plants and animals (and humans) have been exposed and have evolved in this natural background radiation since life first began to form on the earth (3.8 billion years ago for bacteria, 3 billion years ago for photosynthesis, 300 million years ago for dragonflies, 200 million years ago for mammals, 2.5 million years ago for humanoids).