The Sun is the center of our solar system. Our solar system is one of many in the Milky Way Galaxy. The Milky Way Galaxy is one of many thriving galaxies of stars and planets in a cluster of galaxies known as the “Local Group”. There are spiral galaxies. These are galaxies that appear as spirals when seen at a distance. Spiral galaxies have bright centers filled with stars and planets that reflect the light of stars. Spiral galaxies also have curved arms that swirl and wrap around the center like a spiral. There are disc shaped galaxies with bright centers and disc shaped boundaries. Clusters of distant galaxies shine intensely and move in different directions throughout the universe.
The Sun is a massive fireball of interstellar gas and plasma. Plasma is a liquid or a gas, such as hydrogen and helium. The Sun is hot because it burns. The flammable gases in the Sun undergo nuclear fission. Atoms split apart and release energy. Atoms are made of protons, neutrons, and electrons. Neutrons have a neutral charge. Electrons have a negative charge. Protons have a positive charge. Every atom has a certain number of neutrons and protons that make up the nucleus. Orbiting the nucleus are the electrons. Atoms have the same number of electrons as they have protons. Some atoms have more “mass” than others. When an atom splits, the particles break away and hit other atoms, splitting them and releasing energy. These particles continue to hit other atoms, splitting them as well, and so on. Gravity is a product of mass and size. Gases in the core of the Sun remain dense and compact. Tons of gases in the Sun are squeezed into compact flares that undergo this nuclear fission, known as “solar flares”, explosions that happen near the surface. Remote sensing is used to observe things that the eye cannot follow. Looking at the Sun directly is dangerous. So satellites are used to take pictures of the Sun. People can study these pictures. Solar flares can be seen with satellites and remote sensing probes. Because they can be seen with the proper equipment, solar flares provide a good example for the process of nuclear fission that takes place inside the Sun where neither eyes can watch nor equipment can follow. Albert Einstein’s equation Energy equals Mass multiplied by the square of the speed of light explains the process of nuclear fission, where particles traveling at the speed of light break apart and hit other particles, releasing energy in the form of heat and light. “Black Holes” in space are stars that have burned out and have begun to collapse, like wads of paper set on fire that turn into slivers of carbon. Residual matter from Black Holes creates a measurable gravitational force.
Our Solar System consists of nine planets, an asteroid belt, and “satellites”, comets, Moons, and space rocks. The planets orbit the Sun. Mercury is closest to the Sun. Venus is next. Earth is the third planet from the Sun. Mars is the fourth planet away from the Sun. There is an asteroid belt between the Celestial planets and the Jovian planets. Celestial planets are generally smaller. Jovian planets are generally larger. Jupiter is the next planet in line, followed by Saturn, Uranus, Neptune, and a small ice planet named Pluto. Saturn has rings that orbit the planet. These rings are made of space rocks. The origin of these space rocks is a mystery. Are they the remains of a moon or a small planet that broke apart? Many planets in the solar system have moons that orbit. The Earth has a Moon that reflects the light of the Sun and can be seen clearly from the Earth. Light travels from the Sun at about 186,000 miles per second. A light year is the distance light travels in one year. An Astronomical Unit is the average distance between the Earth and the Sun. This light travels through space and reflects off the planets, which is why they can be seen on a clear night from Earth.
Isaac Newton’s Laws of Motion state that every action has an opposite and equal reaction, that a body in motion will remain in motion unless acted upon by another force, and that a body at rest will remain at rest unless acted upon by another force. These principles of physics explain the gravitational pull of the Sun and the Nine Planets, as well as the behavior of the asteroids and comets that travel through the solar system. The Moon has less mass than the Earth and therefore has a lesser gravitational pull than the Earth. This is why the Moon orbits the Earth and not vice versa. The Sun has greater mass and therefore a stronger gravitational pull than the nine planets. This is why the planets orbit the Sun and not the other way around. Meteors from the asteroid belt and from other regions of space occasionally become “free radicals” when comets pass by and disrupt their natural orbit. A free radical travels through space. The gravity of a planet or moon may change its course. Sometimes free radicals impact these bodies in space, such as the moon, and create impact craters that can be seen with telescopes. Meteorites have also hit the Earth and blasted tons of debris into the atmosphere. Most meteorites that hit the Earth burn up in the Earth’s atmosphere. Objects traveling at high speeds encounter tremendous friction with the particles in the atmosphere. Friction creates heat and most objects burn up or disintegrate. A few meteorites are known to have actually hit the Earth, most notably at Tunguska in Russia, and Meteor Crater Arizona, in America.
Binary stars revolve around each other. Binary stars are rare but are very dynamic. Pulsars are stars that spin rapidly. The mass of a Pulsar spins in a compact and dense rotation. Blue Pulsars are blue stars that spin rapidly. Red Dwarf stars are small red stars, large at first glance standards but smaller than other “typical” stars. Red Giant stars are giant stars that shine intense red light. Supernova stars are typically older stars that reach the end of their existence and explode, “going out with a bang”. Such explosions are catastrophic. These are the stars that form the galaxies. These are the stars that NASA studies. SETI is the Search for Extraterrestrial Intelligence. Remote sensing, satellites, and probes search for probable signs of life on other planets in other star systems. NASA is the American National Aeronautic and Space Administration. NASA builds rockets, satellites, and space ships. NASA designs and builds rockets that carry interstellar satellites into space. These satellites travel through the galaxy and transmit photos and statistical data about the planets and moons that only satellites can reach because the distance is currently too long for people to safely travel. NASA also builds space shuttles that can carry a crew of astronauts into Earth orbit and bring them back safely. Space Shuttles are therefore designed with protective blast plates that absorb heat and withstand the high pressure sustained upon re-entry through the Earth’s atmosphere. NASA also developed a rocket propelled Space Capsule that landed on the moon and safely returned with the crew. For such a journey the crew had to wear insulated Space Suits that carried breathable air and protected them from the dangerous vacuum of space. NASA develops these technologies to learn about the galaxy and improve the quality of life here on Earth.