If you are interesting Physic (for Space, Time and other theories) or want to study it, you have to know about Light & Matter. It is a fundamental parts of Physics. Do you know why scientists can say the size of the earth or any star/planet ? They can not measure the actual size of these stars. So Why did he say the size, temperature, weather or somethings else of these object/matter ?
Because of Light. Yes the biggest answer is Light. Scientists can calculate the size (or something) by using the light reflected from these object/matter. Light can carry the details of any object.
So Light is amazing, isn't right? So What is Light and how it work ?
Light is electromagnetic radiation and is a part of the electromagnetic spectrum.
If you want to read about light, read this article
Matter for Beginner
Today, I want to explain what is matter and about its structure. Basically, every object/things are made up of matter. The air, water, even our bodies. The sun, earth, moon and any stars are made up of matter. All matter is made up of tiny particles called atoms. There are electrons, protons and neutrons in an atom. According the structure, quantity, mass and size, matters can be different each other.
Every substance has many types of molecules depending on the structure of its molecules, but there are only more than 100 types of elements that make up molecules. Nitrogen, Hydrogen, Carbon, Oxygen, Iron, Gold, Silver, etc...
You can study these elements in this table called Periodic Table
Now you know all matter can be different size, shape or color according the structure of its atoms. There are also different states and properties.
Solid, Liquid and Gas, its properties are are Melting, Freezing, Sublimation, Vaporization, Condensation and Deposition.
Basically, matter is so simple to understand. Because this explanation is inspired the articles for kids or beginner. It is not easy actually. If you want to read some articles for kids/beginners, You can read here.
Matter for Kids/Beginner Article 1
Matter for Kids/Beginner Article 1
Now time to read about matter more specifically (Scientific View)
Matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume.
More fundamentally, matter is composed of elementary particles called quarks and leptons, both of which are considered elementary particles in that they aren't made up of smaller units of matter. Quarks -- groups of subatomic particles that interact by means of a strong force -- combine into protons and neutrons. Leptons -- groups of subatomic particles that respond to weaker forces -- belong to a class of elementary particles that includes electrons.
An atom is the smallest unit of ordinary matter that forms a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across. They are so small that accurately predicting their behavior using classical physics, as if they were tennis balls for example, is not possible due to quantum effects.
Wiki - Atom
Elements have their own properties. The properties of a molecule are different from those of the elements that make it up. For example, the properties of water H2O are different from hydrogen and oxygen.
If we classify at the materials in detail, we know that they are made up of atoms, so there are more than 100 types of elements, so there are more than 100 types of atoms. Atoms consist of three types of particles: protons, neutrons, and electrons. According to the number of protons in an atom, the elements are divided. If there is one proton, hydrogen. If there are two, helium. For Oxygen, 8 and so on.
Atoms and/or molecules in two or more elements can join together to form a compound. This compound, which is the basis of matter, may not resemble any of the original ingredients.
For example, sodium and chlorine, two highly poisonous elements that are unstable at room temperatures, combine to form one of the most common and harmless compounds known to man called common salt (sodium chloride, or NaCl). Unlike its constituent elements, salt is highly stable, harmless to humans and even edible.
The Structure of Atom
Protons and neutrons are concentrated in the nucleus, which is extremely small even compared to an atom. Outside of the nucleus, electrons spin like a cloud.
In an atom, the nucleus is small and compact, the electron cloud is quite large, but the mass of the whole atom is in the nucleus because the mass of the electrons is too small.
States of matter
I explained state of matter can be different into various form such as solid, liquid and gas according to their atoms' structure. It is more than that, it has another states such as plasma, Bose-Einstein Condensate. So it have their properties above I explained such as melting, freezing, etc...
Energy of matter or Conversion of matter into energy
For further study, we need to know that atoms have different energy levels. Energy levels are not the same as different types of atoms, and the gap between each level is different. Energy level refers to the amount of energy of electrons. The electrons of every atom have levels 1 2 3 and so on up to the ionization level.
In some situations, matter is converted into energy by atomic reactions, also known as nuclear reactions.
Albert Einstein as his theory of relativity:
E = mc2
E is the energy in joules; m is the mass in kilograms; and c is the speed of light, which is approximately 2.99792 x 108 meters per second in a vacuum.
Now, I think you well understand what is matter and its structure in details. I will suggest you to read below articles to read more about matter. And then read further the articles about how to detect the size or something of matter using its reflected light. It is very interesting for beginners and it is very important to know before you study of Physics.
Further Article about Matter
Wiki - about Matter
Britannica - about Matter
Techtarget - defination of Matter
Relationship between Light and Matter
Quora - How do we measure the amount of matter in the universe
Nature - about Matter
Study - interaction between light matter facts ways relationship
Ref : List