To give you a better understanding of how solar energy works, this article will explain the basic tenants of nuclear physics as they relate to solar energy. Some of the concepts covered may be unfamiliar to you and what follows is intended to familiarize you with the basic tenants of nuclear physics that underpin the functioning of the sun and stars.
NUCLEAR PHYSICS
Our sun is approximately 93 million years old and as it continues to churn the hydrogen, helium, and lithium that make up its nucleus, it will eventually consume itself and destroy the solar system.
It is known as “the death star” and it’s a fittingly ironic nickname because the sun is absolutely essential to life on earth. The sun provides heat for the planet, sustains all living things, and regulates climate. Were it not for nuclear physics, our world would be a very different place.
At the center of the sun is a supermassive black hole that devours everything in its path. It is a billion times more massive than the sun and its gravitational pull is so great that even light cannot escape its grasp. This is what gives the sun its brightness. It is also the source of all the energy the sun consumes.
Just as the sun is the source of all solar energy, it is also the source of all nuclear energy. Nuclear energy is produced when a nucleon (neutron + proton) interacts with a photon (light particle) inside a nuclear fission reactor. Fission is the process by which a nucleus undergoes a chain reaction that results in the emission of lighter nuclei and the generation of more free radicals.
When this process happens in nature, it’s usually associated with a star or the core of a star. In a nuclear reactor, however, fission can happen spontaneously with no outside influence. This makes it a source of energy that is completely “green” in its production.
THE NUCLEON
A nucleon is the combination of a neutron and a proton, two of the smallest and most fundamental subatomic particles known to physics. These particles are produced in abundance inside the sun as it turns uranium into helium. As the temperature and pressure increase as a result of the sun’s core swelling with each new turn of the nuclear helix, nucleons are constantly bombarded by photons and eventually suffer enough fissions to become part of the background noise of nature.
The nucleon has a mass that ranges from 1 to 3 GeV and its size is 80–120 fm. It is electrically neutral and slightly asymmetric. Due to its asymmetry, the nucleon has a net charge of +1 or −1.
Because of its instability, the nucleon lives for only a fraction of a second before colliding with another nucleon to create a neutral particle and a small set of free radicals. In order to maintain balance, the universe requires that two nucleons combine to form a nucleus.
NUCLEAR RADIOACTIVITY
When a nucleon suffering from enough fissions interacts with another nucleon or an atomic nucleus, it can undergo a form of radioactive decay that results in the emission of one or more alpha, beta, or gamma particles. These particles are very short-lived, with a fractional life-span measured in nanoseconds, and are able to travel very far before decaying into particles that are easily detected and measured. This makes them ideal “tracers” for investigating the properties of materials through experimentation and observation.
Due to their short lifetime and ability to travel long distances before decaying, alpha, beta, and gamma particles are often used to study the properties and behavior of materials. The detection and measurement of these particles and radiation is at the heart of nuclear physics.
THE NUCLEAR FAMILY
The nuclide is the collective term used when referring to a nucleus and its accompanying set of electrons when they are considered as a single, unified “thing.” The number of nuclides that can be created in a nuclear reactor is virtually limitless and it is dependent on the isotopes available for fission. There are currently 112 known nuclides in existence, ranging in mass number from 3 to 239.
If you want to understand how nuclear energy works, it’s best to start with the elements hydrogen, helium, and lithium. These elements can be combined in great numbers to create the more complex elements that make up the planet. Through fission, almost every atom on earth was once part of a star or a galaxy that eventually became part of the background noise of nature.
NUCLEAR FISSION
Hydrogen is the most common element in the universe. It is the building block of all atoms and almost all (by mass) of the elements on earth. In a star, it is created in great abundance through the fusion of neutrons and protons. As a result of this process, two neutrons and two protons can combine to form a helium nucleus that has two protons and two neutrons in its case (2He+2n→4He). This process, which generates energy in the process, is known as nuclear fusion and it is the basis of all nuclear power generation after the initial splitting of the atom during the Big Bang.
Hydrogen, helium, and lithium are the three basic building blocks of all atoms and almost all (by mass) of the elements on earth. Therefore, these elements are important to the study of nuclear physics and its relation to solar energy. When the energy in a nucleus increases as a result of additional fissions, the nucleus undergoes a period of stability that results in the emission of a lighter nucleus. When this happens multiple times, the emitted nuclei are collectively known as nuclei (H+n→He+n). This process is known as nuclei mass renormalization.
The Heliosphere
The heliosphere is the region of space dominated by the sun. It is often referenced in connection with solar energy because everything inside the heliosphere is affected by the sun’s current state of affairs. For example, the amount of solar radiation that strikes the earth depends on the sun’s position relative to the earth at the time of day. During the day, the radiation is at its peak and reaches its maximum intensity when the sun is directly above the earth. At sunrise and sunset, the radiation is at its minimum. Therefore, the day/night cycle of the earth regulates weather patterns.
The heliosphere encompasses everything from the solar system to the outer limits of the known universe. The earth is located at the center of the heliosphere and is affected by all the electromagnetic radiation that comes in from all directions. Because of this, everyone on earth is part of the heliosphere, including those living on the other side of the globe.
This expansive region of space is bounded by the aurora (which is named after the Northern Hemisphere’s indigenous people who considered the dawn and the evening sky to be beautiful and a testament to the power of nature), the auroral arc, and the polar caps. In addition, the heliosphere is open to the stars, plasma clouds, magnetic field, and gravitational waves.
GRAVITATIONAL WAVES
Gravitational waves are ripples in the gravitational field caused by temporary density fluctuations as a result of very high-energy collisions or interactions that occur at the core of a star. These fluctuations in the gravitational field are extremely small and can only be detected through highly advanced technology, such as laser interferometers and atomic force microscopes. For this reason, gravitational waves are often used in connection with solar research.